Physical science (1)

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PHYSICAL
SCIENCE
QUARTER 1
LEARNING ACTIVITY SHEE

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Learning Activity Sheet in EARTH SCIENCE
(Grade 12)
Copyright © 2020
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NOTE: Practice personal hygiene protocols at all times
Table of Contents
Compentency Code
Page
number
Give evidence for and describe the formation of
heavier elements during star formation ad
evoution S11/12PS-IIIa-2 1 - 20
Explain how the concept of atomic number led
to the synthesis of new elements in the
laboratory S11/12PS-IIIb-11 21 – 33
Determine if a molecule is polar or non-polar
given its structure S11/12PS-IIIc-15 34 – 52
Relate the polarity of a molecule to its
properties S11/12PS-IIIc-16 53 – 69
Describe the general types of intermolecular
forces
S11/12PS-IIIc-d-
17 70 - 79
Explain the effect of intermolecular forces on
the properties of substances
S11/12PS-IIId-e-
19 80 - 100
Explain how the structures of biological
macromolecules such as carbohydrates, lipids,
nucleic acid, and proteins determine their
properties and functions S11/12PS-IIIe-22 100 - 131
Use simple collision theory to explain the
effects of concentrate temperature, and
particles size on the rate of reaction S11/12PS-IIIf-23 132 - 145
Define catalyst and describe how it affects
reaction rate S11/12PS-IIIf-24 146 - 154
Determine the limiting reactant in a reaction
and calculate the amount of product formed S11/12PS-IIIh-27 155 - 174
Describe how energy is harnessed from
different sources:
A. Fossil fuels
B. Biogas
C. Geothermal
D. Hydrothermal
E. Batteries
F. Solar cells
G. Biomass
S11/12PS-IIIi-29 175 - 194

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From product labels, identify the active
ingredient(s) of cleaning products used at home S11/12PS-IIIi-j-31 195 - 209
Give the use of the other ingredients in cleaning
agents S11/12PS-IIIi-j-32 210 - 225

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PHYSICAL SCIENCE
Name: ________________________________________Grade Level: _________
Date: __________________________________________Score:______________
LEARNING ACTIVITY SHEET
INTRODUCTION TO STELLAR EVOLUTION, THEIR SOURCE OF
ENERGY AND THE LIFE CYCLE OF STARS
Background Information for the Learners (BIL)
The Big Bang and the origin of the universe
This diagram shows the
expansion of the universe shortly
after the big bang. The time
increases from left to right, with
important events identified on the
image. The events are represented
by stacked graphs on a time-
continuum. Two of the most
important events with respect to this
lesson are the first stars (~ 400
Million years ago) and the
subsequent development of galaxies and planets.
Under the current cosmological model for the beginning of the Universe, the
“Big Bang” occurred ~13.8 billion years ago. Under this model, the Universe was
extremely hot and dense and an “explosion” caused it to begin expanding rapidly.
After the initial expansion, it then began to cool allowing the energy and matter to
condense to form subatomic particles, such as protons, neutrons and electrons. A few
thousand years later, the first atoms (with stable atomic nuclei) formed. These
“primordial elements” consisted of hydrogen and helium, with some lithium. These
elements later condensed under the force of gravity to form stars, which then formed
https://en.wikipedia.org/wiki/Big_Bang

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heavier elements, either through fusion or during supernovae the first stars began
forming about 400 million years after the Big Bang.
The Hertzsprung-Russel Diagram (HR Diagram) shows the relationship
between the absolute magnitude (luminosity / brightness) of stars and their
temperatures. The brightest stars are toward the top of the diagram while the hottest
stars are on the left of the diagram. The main band that stretches across the diagram
(bottom right to top left) consists of the Main Sequence Stars.
These main sequence stars are in hydrostatic equilibrium, meaning that their
inward gravitational pressure is balanced by outward thermal pressure (generated by
the fusion within the hot core). The main sequence represents the major hydrogen-
burning phase of a star’s lifetime. A general rule is that the larger a star, the shorter its
life span along the main sequence branch.
Following the hydrogen-burning phase, more massive stars can evolve along
the red-giant-branch (RGB) or asymptotic-giant-branch (AGB) stars. These are
represented by the branch in the top right. RGB stars continue to fuse hydrogen in
their cores while AGB stars begin to burn heavier elements such as carbon and
https://en.wikipedia.org/wiki/Hertzsprung–Russell_diagram

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oxygen. While these stars will not be discussed in explicit detail, they are important to
the formation of elements through stellar nucleosynthesis.
What is Stellar Nucleosynthesis?
Elements heavier than beryllium are formed through Stellar nucleosynthesis –
is the process by which elements are formed within stars. The abundances of these
elements change as the stars evolve.
Learning Competency:
Give evidence for and describe the formation of heavier elements during star formation
and evolution (S11/12PS-IIIa-2)
Activity 1: Find Me
...refer to Hertzsprung-Russel Diagram
Questions:
1. What colors are the hottest stars? _________________
2. What colors are the coolest stars? _________________
3. Which stars are the smallest? __________________
4. Which stars are the largest? __________________
5. Which stars are the brightest? __________________
6. Which stars are the dimmest? __________________
7. What classification of star is the hottest? ____________
8. What classification of star is the coolest? ____________
9. What classification is our Sun? __________________
10.What color is our Sun? __________________
11.Compared to other stars what is the Suns temperature?
12.Where does the Sun fit in this diagram?

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Key Points on the Evolution of Stars
There are different evolutionary paths for low-mass stars (like the Sun) and high-
mass stars, but they both begin with growth along the Main Sequence.
Star-forming (stellar) nebula condenses to form proto-stars, which then
condense further to form full-fledged stars. At this point, the core reaches 10 million
Kelvin, which initiates hydrogen fusion, thereby generating energy for the star. The
hydrogen fusion maintains the star through hydrostatic equilibrium (with external
thermal pressure counteracting inward gravitational collapse). This star is currently
on the main sequence, but after the core uses up its hydrogen supply for fusion, the
fate of a star will differ and depends on the size of the star.
...refer to Hertzsprung-Russel Diagram
13. What is the color of the hottest stars?
14.Which classification of stars has the most energy?
a. How is a star’s temperature related to its energy?
b. How is a star’s magnitude related to its energy?
c. How is a star’s luminosity related to its energy?
d. Hypothesize what classifications of stars are at the
beginning of their life cycle and which are at the end of their
life cycle?

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EVIDENCES OF FORMATION OF HEAVIER ELEMENTS THAN BERYLLIUM
In the evolution of stars, they grow and exhaust their fuel, changing to a different
source of energy (i.e. a different element). For a typical main sequence star, the
stars begin producing energy from hydrogen burning (proton-proton fusion).
Eventually, the supply of hydrogen begins to decrease and finally the core is entirely
depleted and consists only of helium.
As the main sequence star glows, hydrogen in its core is converted into helium
by nuclear fusion. When the hydrogen supply in the core begins to run out, and the
star is no longer generating heat by nuclear fusion, the core becomes unstable and
contracts. The outer shell of the star, which is still mostly hydrogen, starts to expand.
As it expands, it cools and glows red. The star has now reached the red giant phase.
It is red because it is cooler than it was in the main sequence star stage and it is a
giant because the outer shell has expanded outward. In the core of the red giant,
helium fuses into carbon. All stars evolve the same way up to the red giant phase. The
The outward push from
thermal pressure
The inward
push from
gravity
The pressure is
generated from
the thermal
energy from
nuclear fusion
in the core
http://woodahl.physics.iupui.edu/Astro105/

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amount of mass a star has determines which of the following life cycle paths it will take
from there.
This results in an expansion of a large, outer-atmosphere of the star, resulting
in a large radius and a low surface temperature. This is a characteristic Red Giant. It
is a luminous giant star with low to intermediate mass (0.3-8 solar masses), and a
relatively low density (because of the expanded radius).
Gravity again squeezes the star. In a low-mass star, there is not enough mass
for a carbon fusion to occur. The star’s fuel is depleted, and overtime, the outer
material of the star is blown off into space. The only thing that remains is hot and inert
carbon core. The star becomes a white dwarf.
A large star (larger than our Sun) that is massive enough to continue past He
burning to carbon, oxygen and silicon burning will eventually result in a layered
structure (like an onion). Each element begins to burn, the lighter element moves into
a shell around it. Therefore, when the star begins to burn carbon, there would be a
shell of helium-burning, surrounded by another shell of hydrogen-burning. This
continues through to silicon-burning, which deposits iron in the core and continues in
a small shell around it.
During these different stages of fusion, the star is able to balance the inward
force of gravity with outward thermal pressure. This is because of the energy and heat
generated from the fusion in the shells. When fusion stops, however, and the core
consist of Fe, the star can no longer generate energy from fusion. This is because Fe
has a high binding energy and its fusion is an energy-consuming process. Therefore,
the star can no longer balance the inward force of gravity with an outward thermal
pressure; without the generation of heat and energy, the star will collapse and then
explode into a supernova type II.
Hydrogen burning describes the process in which the fusion of protons
ultimately leads to the formation of a Helium-4 nucleus (also known as an alpha
particle).

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The proton-proton chain reaction consists of three steps.
1. In the first step, two protons fuse at very high temperatures to create a Deuterium
nucleus (in this step, one of the protons actually becomes a neutron, through beta-
plus radioactive decay). Deuterium has an atomic number of 1 and an atomic mass
of 2 and therefore is a heavy isotope of hydrogen.
2. In the second step, the deuterium nucleus fuses with a proton to form a Helium-3
nucleus, which consists of 2 protons and 1 neutron.
3. In the third step, two Helium-3 nuclei fuse together. This is an energetic reaction
that results in the release of 2 protons. The final product is a Helium-4 nucleus, with
2 protons and 2 neutrons; this is also referred to as the alpha particle.
The alpha particle, or Helium-4 nucleus, consists of 2 protons and 2
neutrons. It has an atomic number of 2 and an atomic mass of 4 (sum or protons
and neutrons).
In stars, it is produced during the third step of hydrogen burning (or proton-
proton chain reaction). It is an important particle, because it is not only the end-point
of hydrogen burning, but can produce larger, heavier nuclei during the alpha process.
https://en.wikipedia.org/wiki/Proton–
proton_chain_reaction

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The alpha process (or alpha fusion) is a method by which stars convert helium
nuclei (alpha particles) into heavier elements. Because of the number of protons
and neutrons in an alpha particle, the heavier elements produced by the alpha process
have an even number of protons and neutrons. Elements with odd atomic numbers
can subsequently produce by radioactive decay or from other reactions, such as
during a supernova.
Triple-Alpha Process: Step 1
In the first step, two helium nuclei
combine to form a beryllium
nucleus. There is a conservation of
atomic mass and the resulting
nucleus has 4 protons and 4
neutrons (with an atomic number of
8).
Triple-Alpha Process: Step 2
Here, the beryllium nucleus
formed in the previous step fuses
with an additional alpha particle,
resulting in a carbon nucleus. The
beryllium-8 produced from the
previous reaction is highly unstable
and therefore either decays rapidly
or reacts with an alpha particle to
produce carbon.
It should be noted that not all the
products of fusion in stars are
stable. In this example, the
formation of beryllium-8 is important
for the formation of carbon-12, but
the majority of beryllium actually
formed during the Big Bang (this is
possible because it is such a light
element).
https://en.wikipedia.org/wiki/Proton–proton_chain_reaction

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Chain of Alpha Processes
https://slideplayer.com/slide/12355862/
The general process, in which an alpha particle is added to a nucleus results in
a chain of reactions. This set of reactions is also known as the alpha ladder. It can
form all the even elements from beryllium to iron. The reactions proceed at a very low
rate and do not contribute significantly to the energy production in stars, but are
important for the generation of the elements.
Activity 2: Proton-Proton Fusion Activity!
The students will identify the steps that are involved in the nuclear fusion, and
model them using cotton balls and glue. The purpose of re-creating the diagrams
presented in class is to provide them with a tangible grasp of the material.
Main Theory:
A hydrogen atom has the most basic nucleus in the universe. It is made
up of one proton. In the core of a star the temperature is high enough
(10,000,000K) to start nuclear fusion. Nuclear fusion is the process of
combining nuclei to form new, larger nucleus element. This activity will
go step by step through the process of converting Hydrogen into Helium.

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Part 1
Theory
In the first step, 2 protons combine. In doing so one of the protons will convert
into a neutron by losing a positron (positive electron) and a neutrino; this is also known
as beta decay. Beta decay occurs when, in a nucleus with too many protons or too
many neutrons, one of the protons or neutrons is transformed into the other.
This changes one of the protons (positive charge) into a neutron (neutral charge) and
allows the two particles to combine.
Directions:
1. Come up to the front and collect two white cotton balls and a glue
stick (These white cotton balls represent two protons, so one
hydrogen nucleus each)
2. Glue the cotton balls down to in the proper location, with each proton
representing one hydrogen nucleus.
3. Collect 2 new cotton balls, one white (proton) and one red (neutron).
Glue these down in the correct location, to represent a deuterium
nucleus (the product of the reaction).
4. Let the cotton balls dry and glue them into the proper location.
Part 2
Theory
In the second step, a proton combines with a deuterium nucleus
(produced in step one). This new nucleus will now have 2 protons and
1 neutron, and represent a Helium-3 nucleus. Note that the hydrogen
nuclei combined to form a new element, helium.
Directions:
1. Collect 4 white cotton balls (protons) and 2 red cotton balls (neutrons)
2. On the given worksheet glue the white and red cotton balls in the
proper locations, with the two reacting species consisting of hydrogen
(1 proton) and deuterium (one proton, one neutron). After they
combine, their product can be represented by 2 protons and 1
neutron (Helium-3 nucleus).
Part 3

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Theory
The nucleus from step 2 is a Helium-3 nuclei. In step 3 two Helium-3
nuclei will combine to form a Helium-4 nucleus and release 2 protons
(i.e. 2 hydrogen nuclei). The resulting Helium-4 nucleus is also referred
to as an alpha particle.
Directions:
1. Collect 8 white cotton balls (protons) and 4 red cotton balls (neutrons)
2. On the given worksheet, glue the white and red cotton balls in the
proper locations. The two products should be Helium-3 nuclei, with
2 protons and 1 neutron each (therefore 2 white and 1 red cotton
balls). The product of this reaction is a Helium 4 nucleus (2 protons
and 2 neutrons; 2 white, 2 red). The two protons that are release by
this reaction can be represented by the remaining 2 white cotton balls
(these are individual hydrogen nuclei).
Activity 3: Alpha Fusion Activity!
Objective:
Students understand how heavier elements (Be to Fe) are formed and make
models that show the nuclei of these elements forming.
Directions:
Part 1
1. Get a package of white cotton balls and a package of red cotton balls
2. Each WHITE cotton ball represents 1 PROTON
3. Each RED cotton ball represents 1 NEUTRON
4. Make an Alpha particle by gluing 2 protons (White) and 2 neutrons (Red)
together.
5. After combining, count the total number of protons (white) to find the
atomic number (the number of protons found in the nucleus of every atom
of an element) the new nuclei your created and write it down on your
periodic table. What is this nuclei’s atomic number?

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6. Now count the number of neutrons (red) and ADD that to the number of
protons (white) to find the atomic mass, write it down on your periodic
table. What is this nuclei’s atomic mass?
7. What element has a nucleus like this?
8. On your blank periodic table write in the information in the proper location.
9. Make a second Alpha particle and glue it to the first Alpha particle.
10.What is this nuclei’s atomic number? What is this nuclei’s atomic mass?
What element’s nucleus is this?
11.On your blank periodic table write in the information in the proper location.
12.Make another Alpha particle and glue it to the nucleus
13.What is this nuclei’s atomic number? What is this nuclei’s atomic mass?
What element’s nucleus is this?
14.On your blank periodic table write in the information in the proper location.
15.Repeat steps 13, 14 and 15 until you have an Iron nucleus.
16.What one factor ultimately organizes the elements on the periodic table?
Part 2
1. Look at your periodic table. Are there elements missing between He and
Fe?
Based on the trend that we have been working with, fill in the blank atomic numbers
and atomic masses for the missing elements between He and Fe.
TRY TO THINK ON THIS:
“WE ARE ALL MADE UP OF STARS”
-
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___________________________________________________.

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Activity 4: Plot Me!!
Answer the following questions:
Purpose: Some combinations of neutrons and protons form isotopes
that are not stable and will decay or break apart. This lesson shows
how to predict the proper ratio of protons to neutrons to form stable
isotopes. In nature we find that stable isotopes have an ideal ratio of
protons to neutrons. When charted on a graph (protons vs. neutrons)
we see that stability lies in an area called the band of stability.
Plot the following isotopes on the graph.
Directions: Atomic number and atomic mass is given but the graph has
Neutron on the x-axis and Atomic number on the Y-axis. So the
students must find first the number of neutrons from the given mass
number and atomic number to be plotted in the graph.
24
12Mg 135
60Nd 39
19K 81
35Br 114
44Ru 34
19K
http://www.science.uottawa.ca/eih/ch1/Image4.gif

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1. What does the entire area on the graph represent?
2. What does the black area represent? What is it called?
3. What does the straight line represent?
4. Which elements where charted outside the grey area? What would it indicate
about those elements?
5. There are two K’s (potassium) atoms on the graph. What is it called there are
two atoms of the same element with different atomic masses? What on the
subatomic level, is different between the two atoms?
6. Do all stable atoms have the same number of protons and neutrons?
For more insights visit the link:
https://www.csus.edu/indiv/t/taylorc/SIRC_March22_2011.pdf
Assessment
MULTIPLE CHOICE: Encircle the letter of the correct answer.
1. Which of the following best describes Stellar Nucleosynthesis?
a. a hot cloud of gas where energy is distributed evenly all throughout
b. the formation of atomic nuclei through the combination of hadrons during the
Big Bang
c. the birth of elementary particles in the beginning of time
d. the creation of chemical elements by nuclear reactions within stars.
2. Which of the following is the Heaviest Element?
a. Helium b. Iron c. Carbon d. Silicon
3. What phenomena lead to the formation of Heavy Elements?
a. Cosmic Ray Collisions c. Big Bang
b. Supernovae d. Stellar nucleosynthesis
4. Which of the following is NOT true: Isotopes of the same element ________.
a. have the same number of Neutrons
b. have the same atomic number, but different atomic weights
c. have different number of Neutrons, but the same number of Protons
d. contain the same number of electrons
5. Deuterium and Tritium are isotopes of _____.
a. Hydrogen b. Helium c. Lithium d. Beryllium

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6. All of the Deuterium in our galaxy was formed _____?
a. during the Big Bang c. in fusion reactors of the Earth
b. in Supernovae d. in cosmic ray collisions
7. Which was believed to have produced most Helium in the Universe?
a. red giants b. supernovae c. Big Bang d. main sequence stars
8. Which of the following processes is likely to generate the heaviest element?
a. CNO cycle c. triple-alpha process
b. r-process d. Big Bang nucleosynthesis
9. Lithium and Beryllium are both light elements and are believed to have been
produced in trace amounts during Big Bang. These elements, however, have a
relatively short half-life and could not have survived to the present. If so, where can
present-time Lithium and Beryllium in the universe have come from?
a. emitted during supernova explosions c. upon cosmic ray collisions
b. produced during stellar evolutions d. a by-product of the birth of a star
10. What isotope is formed in the diagram below?
a. Helium-8
b. Lithium-8
c. Beryllium-8
d. Oxygen
11. Which of these is a portion of the electromagnetic spectrum that can go through
the Earth’s atmosphere?
a. X-ray `light’ b. Ultraviolet light c. Gamma-ray light’ d. Visible-wavelength light
12. In what part of the Hertzsprung-Russell diagram would you find the brightest,
hottest main-sequence stars?
a. The upper-left part of the diagram
b. Along the right-hand edge of the diagram
c. The lower-right part of the diagram
d. Along the lower edge of the diagram
13. What is the Sun made of?
a. Mostly oxygen, with a small amount of hydrogen and helium.
b. Mostly hydrogen, with a little helium, and a very small proportion of heavier
elements.
c. Mostly helium, with the rest being mostly various heavy elements, and a very
small proportion of hydrogen.
d. Mostly iron, similar to the hot iron core of the Earth, with a little bit of helium
and some heavier elements.
14. Which of the following processes is likely to generate the heaviest element?
a. CNO cycle c. triple-alpha process
??

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b. r-process d. Big Bang nucleosynthesis
15. Which of the following reactions is not a part of the alpha ladder?
a. 24
12Mg + 4
2He ---→ 28
14Si c. 36
18Ar + 4
2He ---→ 40
20Ca
b. 31
15P + 4
2He ---→ 35
17Cl d. 44
22Ti + 4
2He ---→ 48
24Cr
16. If an element is used up by a star in fusion, it is sometimes called “burning”, even
though no actual combustion occurs. Which of the following processes is likely to
involve “carbon burning”?
a. alpha ladder c. triple-alpha process
b. CNO cycle d. s-process
7-10. Modified True or False: If the statement is true, write True. Otherwise, replace
the underlined portion with the correct word or phrase.
__________________ a. A star gets lighter as time goes on.
__________________ b. Most of the heaviest elements were formed in main-
sequence stars.
__________________ c. The heavy elements in a star are found in its core.
__________________ d. In stellar nucleosynthesis, heavier elements are formed
from combining lighter ones.
Reflection
1. I learned that __________________________________________________
_____________________________________________________________
_______________________________________________________
2. I enjoyed most on ______________________________________________
_____________________________________________________________
_________________________________________________
3. I want to learn more on __________________________________________
_____________________________________________________________
_________________________________________________
References:
K to 12 Curriculum Guide, page 1of 17

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https://www.coursehero.com/file/52900814/Lesson-2-Formation-of-Heavier-Elementspptx/
https://earthref.org/SCC/lessons/2012/nucleosynthesis/
http://en.wikipedia.org/wiki/Electromagnetic_spectrum
http://en.wikipedia.org/wiki/Hertzsprung%E2%80%93Russell_diagram
http://upload.wikimedia.org/wikipedia/commons/6/6b/HRDiagram.png
Bigbang: http://en.wikipedia.org/wiki/Big_Bang
Redshift: http://en.wikipedia.org/wiki/Redshift
Stellar Evolution: http://en.wikipedia.org/wiki/Stellar_evolution
Supergiant: http://en.wikipedia.org/wiki/Supergiant
Supernova: http://en.wikipedia.org/wiki/Supernova
Wolf-Rayet Star: http://en.wikipedia.org/wiki/Wolf%E2%80%93Rayet_star
Stars (NASA): http://imagine.gsfc.nasa.gov/docs/science/know_l2/stars.html
Main Sequence Stars: http://en.wikipedia.org/wiki/Main_sequence
Hydrogen Burning: http://en.wikipedia.org/wiki/Hydrogen_burning#Hydrogen_burning
Proton-proton chain reaction:
http://en.wikipedia.org/wiki/Proton%E2%80%93proton_chain_reaction
Alpha Process: http://en.wikipedia.org/wiki/Alpha_process
Stable Nuclide: http://en.wikipedia.org/wiki/Stable_nuclide
Radioactive Decay: http://en.wikipedia.org/wiki/Radioactive_decay
Answer Key
Activity 1.Find Me!

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Questions:
1. What color are the hottest stars? Blue
2. What color are the coolest stars? Red
3. Which stars are the smallest? White Dwarfs
4. Which stars are the largest? Supergiants
5. Which stars are the brightest? Blue (main-sequence or supergiants)
6. Which stars are the dimmest? White Dwarfs
7. What classification of star is the hottest? Blue Supergiants
8. What classification of star is the coolest? Red (main-sequence or giants)
9. What classification is our Sun? Main Sequence Star
10. What color is our Sun? Yellow
11. Compared to other stars what is the Suns temp? Average (~5000 K)
12. Where does the Sun fit in this diagram? Yellow, along main-sequence
13. What is the color of the hottest stars? Blue and White
14. Which classification of star has the most energy? Blue and White (also, hottest)
a. How is a star’s temperature related to its energy?
The hotter the star, the more energy it has
b. How is a star’s magnitude related to its energy?
Along the main sequence, stars of greater magnitude are hotter (have more
energy)
c. How is a star’s luminosity related to its energy?
For main-sequence stars, the luminosity increases with temperature. For the
giants and super-giants, large (high magnitude) and luminous stars are actually
quite cool.
d. Hypothesize what classification of stars are at the beginning of their life cycle
and which are at the end of their life cycle?
Hotter stars are younger, cooler stars are older. Giants and super-giants are
dying. White dwarfs are also at the end of a life cycle. The main-sequence
stars show a strong relation between temperature (energy) and magnitude and
brightness—the hotter ones of these are younger.
Activity 4. Plot Me
Answer the following questions:
1. What does the entire area on the graph represent?
It represents all the possible nuclides that can form, including those that will
decay because they are unstable.
2. What does the black area represent? What is it called?
It is the “valley of stability” and represents all the stable nuclides that can exist.
3. What does the straight line represent?
It has a slope of one and shows the expected trend for atoms with the same
number of neutrons and protons in their nuclei.
4. Which elements where charted outside the grey area? What would it indicate
about those elements?

19
All nuclides that cannot form, because they are never unstable
5. There are two K’s (potassium) atoms on the graph. What is it called there are
two atoms of the same element with different atomic masses? What on the
subatomic level, is different between the two atoms?
They are called isotopes. They have a different number of neutrons in their
nuclei, but the number of protons is the same.
6. Do all stable atoms have the same number of protons and neutrons?
No, as atoms get larger, they typically have more neutrons than protons
Assessment
TRY TO THINK ON THIS!:
“The idea that “We are all made of stars” is true, because the formation
of the elements occurs in stars and supernovae. These atoms then become the
building blocks of planets and also the life that has come to evolve on Earth. “
Prepared by:
JOLLY MAR D. CASTANEDA
Baggao National Agricultural School-Sta Margarita Annex
PHYSICAL SCIENCE
Name: ____________________________ Grade Level: _________
Date: _____________________________ Score: ______________
1.D
2.B
3.D
4.C
5.A
6.A
7.C
8.B
9.A
10.C
11.B
12.A
13.B
14.B
15.B
16.A
17.HEAVIER
18.SUPERNOVA
19.TRUE
20.TRUE

20
SYNTHESIS OF NEW ELEMENTS IN THE LABORATORY
Chemists within the 19th
century generally approves about what particles
consisted matter and agreed that matter is made of atoms. However, they are not
familiar about the structure of the atoms.
The information about the known elements gave them encouragement to
arrange the elements in a table.
An element is a substance that cannot be broken down into simpler one. Most
known chemical elements are found to occur on Earth naturally. All elements are all
represented by their atomic number, the number of protons in their nucleus. The
natural elements start with hydrogen (1) and end with californium (98).
But it doesn't stop there. Scientists have created 20 other synthetic elements.
Those start with einsteinium —99. You could also consider atomic numbers 95–98
synthetic elements because they’re almost exclusively man-made that results to a total
of 24 synthetic elements discovered. These elements are generally used to fuel
chemical reactors, and these could also be used for detectors and
spectrophotometers. Some are applicable in pharmaceutical industries.
Source: https://en.wikipedia.org/wiki/Synthetic_element
Naturally - Occurring
and Synthetic Elements

21
The table shows the naturally-occurring and synthetic elements. A synthetic
element is one of 24 chemical elements that do not occur naturally on Earth: they have
been created by human manipulation of fundamental particles in a nuclear reactor,
a particle accelerator, or the explosion of an atomic bomb; thus, they are called
"synthetic", "artificial", or "man-made". The synthetic elements are those with atomic
numbers 95–118, as shown in purple on the accompanying periodic table and the rest
are the naturally-occurring elements.
Different elements have different number of protons. Atomic number is equal to
number of protons. All atoms of a given element have the same number of protons but
may have different number of neutrons and atoms of the same element with different
number of neutrons are called isotopes.
Source: http://terpconnect.umd.edu/~wbreslyn/chemistry/isotopes/isotopes-of-hydrogen.html
Discoveries through Nuclear Reactions
Radioactivity is a spontaneous process wherein the nucleus of an unstable
atom disintegrates while releasing radiation and losing energy. It is also called
radioactive decay or nuclear decay. Antoine-Henri Becquerel discovered
radioactivity in 1896. Using the concept of radioactivity, Ernest Rutherford and
Frederick Soddy discovered isotopes in 1914.
In 1919, Rutherford discovered that when a nitrogen nucleus was bombarded
with alpha particles from radium, an oxygen nucleus and a proton were produced.
In 1934, Irene Joliot-Curie and her husband Frederic Joliot discovered that
when an aluminum nucleus was bombarded with alpha particles, a phosphorous
nucleus and a neutron can be produced.

22
Glenn Theodore Seaborg was an American chemist whose contribution in the
synthesis, discovery and study of ten transuranium elements earned him a share of
the 1951 Nobel Prize/honor in Chemistry.
Seaborg was the head or co-discoverer of ten
elements: plutonium, americium, curium, berkelium, californium, einsteinium, fermiu
m, mendelevium, nobelium and seaborgium. According to him, Uranium or plutonium
are being bombarded with neutrons in nuclear reactors. The first production is in 1944.
NUCLEAR REACTION
Nuclear Reaction a term implied that causes a nuclide to change by
bombarding it with energetic particle. It involves a heavy target nucleus and a light
bombarding particle. It can produce a heavier product nucleus and emits a very high
electromagnetic energy. Nuclear reactions may increase or decrease the number of
protons of an atom, thus, producing new elements or isotopes.
SYNTHETIC ELEMENTS
A term for chemical element that does not occur naturally on Earth. It can only
be created artificially, and it is radioactive and decay rapidly into lighter elements. It
only occurs on Earth as the product of atomic bombs or experiments. Scientist
discovered that a nucleus with too many or too few neutrons compared to its protons
is radioactive. Radioactive materials are very unstable. Technetium with an atomic
number of 43 is the first synthetic element that is artificially produced. It was produced
by E. Segre and C. Perrier in 1937 by bombarding molybdenum nuclei with deuterium.
In 1940, neptunium is produced by bombarding uranium atoms with neutrons. Since
then, elements with atomic numbers 95 to 118 have been synthesized.
Explain how the concept of atomic number led to the synthesis of new elements in the
laboratory (S11/12PS-IIIb-11)
Activity 1: Natural or Synthetic?

23
Material: Paper and pen
Periodic Table of Elements
Source: https://www.slideshare.net/JhayGonzales/synthesis-of-the-new-elements-in-the-laboratory
Procedure: Identify whether the given element is natural or synthetic.
Element Natural/Synthetic
1. Fermium
2. Chromium
3. Curium
4. Nobelium
5. Helium
6. Bohrium
7. Calcium
8. Cadmium

24
9. Copernicium
10. Americium
Q1. What is the difference between natural and synthetic elements?
______________________________________________________________
______________________________________________________________
Activity 2: Identify Me
Materials: Activity notebook/pen
Procedure: Identify what is ask in the given statement below. Write your answer on
the space provided for.
__________ 1. A substance that cannot be broken down into simpler one.
__________ 2. These are the atoms with the same number of protons but
with different number of neutrons.
___________ 3. It is the subatomic particle that disintegrates in the
radioactive decay.
___________ 4. The discovery of ________ led to the discovery of isotopes.
___________ 5. It is the first synthetic element produced.
___________ 6. It is the subatomic particle that determines the atomic
number of an element.
___________ 7. It occurs on Earth as the product of atomic bombs or
experiments
___________ 8 - 10. Synthetic elements are artificially produced through the
process of ________.
Activity 3: My Discovery
Direction: Match column A to column B. This is all about the contributions of the
different scientist to the synthesis of new elements in the laboratory.
COLUMN A
1. Ernest Rutherford
2. Frederick Soddy
3. Antoine-Henri
Becquerel
COLUMN B
a. Discovered that when an aluminum nucleus
was bombarded with alpha particles, a
phosphorous nucleus and a neutron produced.
b. He was the first to produce oxygen nuclei and
protons by bombarding nitrogen nuclei with alpha
particle.

25
Activity 4: Research on Me!
Materials: Reading materials/books
Activity notebook/pen
Procedure: Research on how the given discovered/synthesized elements are
produced in the universe.
Put your answer here.
1. Curium
2. Berkelium
3. Californium
4. Mendelevium
5. Nobelium
6. Lawrencium
7. Dubnium
8. Copernicium
9. Hassium

26
Activity 5: Think About It!
Direction: Explain briefly the following questions below.
1. What is the contribution of atomic number in synthesizing new elements?
___________________________________________________________________
___________________________________________________________________
____________________________________________________
2. How are elements synthesized in the laboratory?
___________________________________________________________________
___________________________________________________________________
____________________________________________________
3. How many elements are man-made? naturally occurring?
___________________________________________________________________
___________________________________________________________________
____________________________________________________
4. What are the common characteristics of all synthetic elements?
___________________________________________________________________
___________________________________________________________________
____________________________________________________
5. What are the uses of synthetic element?

27
___________________________________________________________________
___________________________________________________________________
____________________________________________________
REFLECTION:
1. I learned that _________________________________________________
___________________________________________________________________
_________________________________________________________
2. I enjoyed most on ______________________________________________
___________________________________________________________________
_________________________________________________________
___________________________________________________________________
_________________________________________________________
References:
slideshare.net/JhayGonzales/synthesis-of-the-new-elements-in-the-laboratory
www.slideshare.net>bRoKendaRkaNgeI03>6-concept-of-atomic-no
https://www.angelo.edu/faculty/kboudrea/periodic/physical_natural.htm
https://www.vox.com/2014/5/8/5684538/new-chemical-element-117
www.ucoclick.org
https://en.wikipedia.org/wiki/Glenn_T._Seaborg
https://www.quora.com/How-does-the-idea-of-an-atomic-number-lead-to-
synthesizing-new-elements
https://en.wikipedia.org/wiki/Synthetic_element

28
ANSWER KEY
Activity 1: NATURAL OR SYNTHETIC?
Element Natural/Synthetic
1. Fermium Synthetic
2. Chromium Natural
3. Curium Synthetic
4. Nobelium Synthetic
5. Helium Natural
6. Bohrium Synthetic
7. Calcium Natural

29
8. Cadmium Natural
9. Copernicium Synthetic
10. Americium Synthetic
Q1. What is the difference between natural and synthetic elements?
Natural elements are found naturally occurring in the universe while synthetic
elements do not occur naturally, it has to be synthesized or made by humans to
form that element.
Activity 2: IDENTIFY ME
Element 1. A substance that cannot be broken down into simpler
one.
Neutron____ 2. These are the atoms with the same number of protons but
with different number of neutrons.
Nucleus____ 3. It is the subatomic particle that disintegrates in the
radioactive decay.
Radioactivity 4. The discovery of ________ led to the discovery of isotopes.
Technetium_ 5. It is the first synthetic element produced.
Proton __ 6. It is the subatomic particle that determines the atomic number
of an element.
Synthetic elements 7. It occurs on Earth as the product of atomic bombs or
experiments
8 - 10. Synthetic elements are artificially produced through the process
of _________
8. Radioactive decay
9. Bombardment of Nucleus
10. Nuclear reaction
Activity 3: MY DISCOVERY
1. B
2. D
3. E

30
4. A
5. C
Activity 4: RESEARCH ON ME!
Put your answer here!
1. Curium (Cm) - produced by bombarding uranium or plutonium with
neutrons in nuclear reactors.
2. Berkelium (Bk) - produced by bombarding lighter actinides uranium
(238U) or plutonium (239Pu) with neutrons in a nuclear
Reactor.
3. Californium (Cf) - made by bombarding berkelium-249 with neutrons.
4. Mendelevium (Md) - discovered by bombarding einsteinium with
alpha particles in 1955. Bombarding plutonium and
americium targets with lighter ions of carbon and nitrogen.
5. Nobelium (No) - can only be produced in particle accelerators by
bombarding lighter elements with charged particles and
can also produce by bombarding actinide targets to neutron.
6. Lawrencium (Lr) - 266Lr isotopes are produced only as alpha decay
products of dubnium and 255Lr to 262Lr can all be
produced by bombarding actinide (americium to
einsteinium) targets with light ions (from boron to neon).
7. Dubnium (Db) - synthesized the element by bombarding a

31
Activity 5: THINK ABOUT IT
1. What is the contribution of atomic number in synthesizing new elements?
The concept of atomic number is that every element is categorized by the
number of protons in its nucleus. Each element corresponds to a specific
number and vice versa that helped explain the gaps of the periodic table that
were already filled.
2. How are elements synthesized in the laboratory?
They were synthesized in nuclear reactors or particle accelerators. Nuclear
reactions may increase or decrease the number of protons of an atom, thus,
producing new elements.
3. How many elements are manmade? naturally occurring?

32
Out of 118 elements that have been identified in the periodic table, 24 elements
are considered as artificial or manmade and 94 are naturally occurring elements
in the universe.
4. What are the common characteristics of all synthetic elements?
The mechanism for the formation of a synthetic element is to force additional
protons onto the nucleus of an element with an atomic number lower than
95. All synthetic or artificial elements are not stable, but they decay at a long
period of time.
5. What are the uses of synthetic element?
They used to fuel chemical reactors, it can also be used for detectors and
spectrophotometers and some are used in pharmaceutical industries.
Prepared by:
SHAROLYN T. GALURA
Licerio Antiporda Sr National High School-Dalaya Annex
PHYSICAL SCIENCE
Name: ____________________________ Grade Level: _________
Date: _____________________________ Score: ______________
THE POLARITY OF A MOLECULE BASED ON ITS STRUCTURE
A molecule could be a group of atoms. It’s the tiniest unit that may participate
during a chemical reaction.
There are many different types of molecules, and each one of those molecules
may be categorized into polar and non-polar groups. They are separated from each
within the presence or absence of electric poles. Let’s explore further: There are many

33
different molecules, and there are many ways to sort them. A way to classify them
relies on polarity. Polarity means having dipoles, a positive and a negative end. Based
on polarity, molecules can be polar or nonpolar. Some samples of polar molecules are
water, alcohol and ammonia and non-polar molecules are hydrocarbons like gasoline,
methane, ethylene and diatomic molecules (O2, N2, etc.)
Polar molecules have dipoles. Dipole moment is use to measure the polarity
of a chemical bond between two atoms in a molecule. Their dipole moments of polar
molecules don’t add up to zero (or don’t cancel out). In polar molecules, we see that
the charge is not uniformly distributed. It’s electrically asymmetric, that is, the electrical
charges are not equally distributed. When a highly electronegative atom bond with a
comparatively less electronegative atom, a polar molecule is made. It interacts with
other molecules of the same polarity to form solutions. Water and carbon monoxide
are examples of polar molecules.
Nonpolar molecules do not have positive or negative ends. Their dipole
moments add up to zero (they cancel out). It is electrically symmetric, that is the
electrical charges are uniformly distributed. Most of the hydrocarbons liquids are
nonpolar. Nonpolar molecules do not interact the same way. If two combining atoms
have similar or equal electronegativity values, the bond formed is nonpolar. Carbon
tetrachloride and methane are examples of nonpolar molecules.
Source: https://saylordotorg.github.io/text_general-chemistry-principles-patterns-and-applications-v1.0/s12-09-polar-covalent-
bonds.html
Both types of molecules go by “like dissolves like” principle, which means that
polar molecules can dissolve into other polar molecules and nonpolar into other non-
polar molecules. Polar cannot dissolve into non-polar molecules and vice versa.

34
In terms of electronegativity difference, polar molecules has electronegativity
difference between 0.5 & 1.9 while nonpolar molecules have electronegativity
difference of 0.4 & less.
Source: https://www.wikihow.com/Calculate-Electronegativity
Example:
1. HCl
EN of H = 2.1
EN of Cl = 3.0 ΔEN = 0.9
2. H2O
EN of H = 2.1
EN of O = 3.5 ΔEN = 1.4
Elements with the higher EN value become the partial negative pole while
elements with the lower EN value become the partial positive pole. This makes the
molecule a polar molecule.
Generally, you can tell if a molecule is polar or nonpolar based on its structure
or shape and the polarity of the individual bonds present in the molecule. Bond
polarity is a useful concept for describing the sharing of electrons between atoms
• A nonpolar covalent bond is one in which the electrons are shared equally
between two atoms
• A polar covalent bond is one in which one atom has a greater attraction for
the electrons than the other atom. If this relative attraction is great enough, then
the bond is an ionic bond
Example: H2, N2 --- polar
H-H, N-N
HCl, CO ---non-polar

35
CO2 , there is electrical symmetry therefore it is nonpolar.
C-O is polar but if we consider the whole O=C=O due to symmetry then it is
nonpolar.
Emphasize the possibility of having a polar bond between two atoms but if we
consider the structure of the whole molecule it turns out to be nonpolar.
HCN, it is electrically asymmetric therefore it is polar.
Molecular Geometry
The valence shell electron pair repulsion theory or VSEPR theory helps predict
the spatial arrangement of atoms in a polyatomic molecule. The shapes are designed
to minimize the repulsion within a molecule. Symmetry plays an important role in
determining the polarity of a molecule.

36
Source: https://www.pinterest.ph/ali_sajid29/boards/

37
Source:
https://ontrack-media.net/gateway/chemistry/g_cm3l4rs5.html
Guidelines to determine the Valence shell electron pair repulsion theory
(VSEPR) shape of a molecule:
1. Determine the central atom of a molecule. The central atom is the least
electronegative element.
2. Count how many valence electrons the central atom has.
3. Count how many valence electrons the side atoms have.
4. Create the appropriate Lewis structure of the molecule.
5. Using the Lewis structure as a guide, the appropriate VSEPR shape
for the molecule.
6. Note how many electrons are shared and unshared. This will help determine
the appropriate VSEPR shape. Lone pairs has a big factor in making a
molecule polar.

38
Steps in Determining the Polarity of a Molecule
1. Draw the correct Lewis structure and molecular geometry of the molecule.
2. Identify the polarity of each bond present in the molecule. A bond is polar when the
atoms in the bond have different electronegativity. Recall that electronegativity is the
measure of the tendency of an atom to attract a bonding pair of electrons. (You may
use the periodic table to determine the electronegativity values of the atoms.)
3. Draw the dipole moment vectors for polar bonds. The dipole moment vector points
to the more electronegative atom.
Source: http://www.ochempal.org/index.php/alphabetical/c-d/dipole-moment/
4. Determine the sum of the dipole moment vectors. If the dipole moments cancel out
each other, the molecule is nonpolar; otherwise, it is polar.
Example 1:
Carbon dioxide (CO2) is the gas that you exhale.
1. Correct Lewis structure and geometry:
Source: https://www.makethebrainhappy.com/2018/01/lewis-dot-structure-for-CO2.html
2. Oxygen is more electronegative than carbon. Therefore, the C—O bonds are polar.
Source: dashboard.dublinschools.net electronegativity of CO2
3. Since CO2 has a linear symmetrical structure, the dipole moments of the C—O
bonds cancel out.
Therefore, CO2 a nonpolar molecule.
Example 2:

39
Sulfur dioxide (SO2) is a colorless toxic gas formed by burning sulfur in air.
1. Correct Lewis structure and geometry:
Source: https://chemistry.stackexchange.com/questions/87057/lewis-structure-of-SO2
2. Oxygen is more electronegative than sulfur. Therefore, the S—O bonds are polar.
Source: https://www.toppr.com/ask/question/statement-1-the-molecule-SO2-has-a-net-dipolestatement-2-oxygen-has-the-
higher-electronegativity/
3. Since the molecule is bent-shaped, the dipole moments do not cancel out.
Therefore, SO2 is a polar molecule.
Tip: Note that the shape or structure does not directly determine whether the molecule
is polar or nonpolar. However, you need to know the shape of the molecule to know if
the dipole moments cancel out.
Are all bent molecules polar?
Mostly, yes. As aforesaid, bent molecules are asymmetrical just like trigonal
pyramids and that means that they are polar molecules.
The Exceptions
There are a few exceptions to the rules of polar and nonpolar molecules, and
C-H bond is a classic example. This molecule is nonpolar even though the bonds are
slightly polar. Nitrogen trichloride (NCl3) is a rare example. Nitrogen and chlorine are
both electronegative. That’s why their bond (N-Cl) is non-polar. However, when you

40
see the NCl3 molecule, you will see that the nitrogen atom has a single pair of
electrons. This makes the molecule polar by nature. Sulfur trioxide (SO3) and Boron
trihydride (BH3) are other examples. They have polar bonds, but they are nonpolar in
nature. Ozone or trioxygen (O3), on the other hand, has a nonpolar bond but is polar
by nature.
This Learning Activity Sheets composed of different interesting activities which
will make you enjoy learning. Are you ready? You may now start to learn this topic.
Determine if a molecule is polar or non-polar given its structure (S11/12PS-IIIc-15)
Activity 1: Polar and Non-polar Bond
Direction: Identify the following molecules whether polar or nonpolar (it is possible
to have a polar bond between atoms but nonpolar molecule.)
Formula Polar or Nonpolar
Molecules
1. NF
2. HCl
3. N2
4. CS2
5. N2O
6. O3
7. NI3
8. Br2
9. CH2O
10.BCl3

41
Q1. How are polar molecules different from nonpolar?
______________________________________________________________
______________________________________________________________
Q2. What types of elements combine to form a polar molecule and a non-polar
molecule?
______________________________________________________________
______________________________________________________________
Activity 2: Electronegativity Difference
Source: http://curriculum.nismed.upd.edu.ph
Procedure: Complete the table below by determining the electronegativity
difference between the bonded atoms and classify them whether
the molecules are polar or nonpolar.
Complete the table below.
No. Bonded Atoms Electronegativity
Difference
Polar or Nonpolar
Molecules
1. H - O (in H2O)
2. Cl - Cl (in Cl2)
3. N - H (in NH3)

42
4. C - H (in CH4)
5. H – H (in H2)
6. C – P
7. F – Cl
8. Fe – O
9. P - Cl
10. I – I
Q1. What is the difference between polar and nonpolar molecules in terms of their
electronegativity difference?
_____________________________________________________________
_____________________________________________________________
Q2. What is electronegativity?
_____________________________________________________________
_____________________________________________________________
Activity 3: Electronegativity Difference
Procedures:
1. Draw the Lewis structure and describe the molecular geometry of the following
molecules.
2. Determine if a molecule is polar or non-polar given its structure.
Formula Lewis Structure Molecular
Geometry
Polar or
Nonpolar
1. NH3
2. CH4

43
3. PCl5
4. CCl4
5. F2
6. HF
7. O3
8. NCl3
9. CHN
10. CH2O
Q1. Why is it that homo-nuclear diatomic molecules always form nonpolar bond?
______________________________________________________________
______________________________________________________________
Q2. How many nonbonding pairs of electrons did the polar molecules have?
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
Q3. How many nonbonding pairs of electrons did the nonpolar molecules have?
______________________________________________________________
______________________________________________________________
______________________________________________________________
Activity 4: True or False

44
Direction: Label the following statements as True or False. If the statement is
false, underline the word/s that make it false and change it to make
it true.
_____ 1. In a nonpolar bond, the electronegativity difference of the bonded
atoms should be 0.4 or less
_____ 2. In a polar bond, electrons are shared between atoms.
_____ 3. A nonpolar molecule has a dipole
_____ 4. In a polar bond, the electronegativity difference of the atoms must be
greater that 1.9
_____ 5. Nonpolar molecules have positive or negative ends.
Activity 5: Who Am I?
Direction: For each of the following Lewis structure, determine the shape/molecular
geometry of each molecule and identify whether it is a polar or nonpolar molecule.
1. 6.
2. 7.
3. 8.

45
4. 9.
5. 10.
Reflection:
1. I learned that ______________________________________________________
___________________________________________________________________
_________________________________________________________
2. I enjoyed most on __________________________________________________
___________________________________________________________________
_________________________________________________________
3. I want to learn more on ____________________________________________
___________________________________________________________________
_________________________________________________________
References:
The Polarity of a Molecule Based on Its Structure by Warlito Zamora Canoy
https://web.facebook.com/notes/physical-science/lesson-31-the-polarity-of-a-molecule-
based-on-its-structure/2001514873198061/?_rdc=1&_rdr
https://www.slideshare.net/MarjorieBrondo/lesson-8-physical science?from_action=save
OldSite Vanden Bout. (2011). VSEPR Theory: Introduction. https://www.youtube.com/
watch?v=keHS-CASZfc

46
www.sachs.gsacrd.ab.ca˃eteacher_download
www.ohsd.net˃cms˃lib˃Centricity˃Domain
www.everettcc.edu˃program˃support˃tutoring-center˃chemistry
https://www.mikeblaber.org/oldwine/chm1045/notes/Bonding/Polarity/Bond05.htm
https://www.pinterest.ph/ali_sajid29/boards/
ANSWER KEY
Activity 1: POLAR AND NONPOLAR BOND
Formula Polar or Nonpolar
Molecules
1. NF Polar
2. HCl Polar
3. N2 Nonpolar
4. CS2 Nonpolar
5. N2O Polar
6. O3 Nonpolar
7. NI3 Polar

47
8. Br2 Nonpolar
9. CH2O Polar
10.BCl3 Polar
Q1. How are polar molecules different from nonpolar molecules?
Polar molecules – are asymmetric, containing lone pairs of electrons on a
central atom; electrons are shared unequally.
Nonpolar – symmetric, all the sides around the central atom are identical-
bonded to the same element with no unshared pair of electrons.
Q2. What types of elements combine to form a polar molecule and a non-polar
molecule?
Polar molecules – between nonmetals with different electronegativities
Nonpolar – between multiple atoms of the same element
Activity 2: ELECTRONEGATIVITY DIFFERENCE
Complete the table.
No. Bonded Atoms Electronegativity
Difference
Polar or Nonpolar
Molecules
1. H - O (in H2O) 1.4 Polar
2. Cl - Cl (in Cl2) 0 Nonpolar
3. N - H (in NH3) 0.9 Polar
4. C - H (in CH4) 0.4 Nonpolar
5. H – H (in H2) 0 Nonpolar
6. C – P 0.4 Nonpolar
7. F – Cl 0.8 Polar
8. Fe – O 1.6 Polar
9. P - Cl 1.0 Polar
10. I – I 0 Nonpolar

48
Q1. What is the difference between polar and nonpolar molecules in terms of their
electronegativity difference?
Polar molecules has electronegativity difference between 0.5 & 1.9 while
nonpolar molecules have electronegativity difference of 0.4 & less.
Q2. What is electronegativity?
Electronegativity is the ability for an atom in a molecule to attract electrons to
itself.
Activity 3: ELECTRONEGATIVITY DIFFERENCE
Formula Lewis Structure Molecular
Geometry
Polar or Nonpolar
1. NH3 Trigonal
pyramidal
Polar
2. CH4 Tetrahedral Nonpolar
3. PCl5 Trigonal
bipyramidal
Polar
4. CCl4 Tetrahedral Nonpolar
5. F2 Linear Nonpolar

49
6. HF Linear Polar
7. O3 Bent Nonpolar
8. NCl3 Trigonal
pyramidal
Polar
9. CHN Linear Polar
10. CH2O
Trigonal planar Polar
Q1. Why is it that homo-nuclear diatomic molecules always form nonpolar bond?
Homo-nuclear diatomic molecules always form nonpolar bond because of the
equal distribution of electrons.
Q2. How many nonbonding pairs of electrons did the polar molecules have?
1 or 2
Q3. How many nonbonding pairs of electrons did the nonpolar molecules have?
Zero (0)
Activity 4: TRUE OR FALSE
True 1. In a nonpolar bond, the electronegativity difference of the bonded
atoms should be 0.4 or less
True 2. In a polar bond, electrons are shared between atoms.
Polar 3. A nonpolar molecule has a dipole.
Between 0.5 to 1.9 4. In a polar bond, the electronegativity difference of the
atoms must be greater than 1.9.
Do not have 5. Nonpolar molecules have positive or negative ends.

50
Activity 5: WHO AM I?
1. 6.
Linear, Polar
Tetrahedral, Polar
2. 7.
Linear, Nonpolar
Trigonal planar, Polar
3. 8.
Linear, Polar
Trigonal pyramidal, Polar
4. 9.
Linear, Nonpolar
Bent, Nonpolar
5. 10.
Linear, Nonpolar
Trigonal pyramidal, Polar

51
Prepared by:
SHAROLYN T. GALURA
Licerio Antiporda Sr National High School- Dalaya Annex
PHYSICAL SCIENCE
Name: ____________________________ Grade Level: _________
Date: _____________________________ Score: ______________
POLARITY OF A MOLECULE TO ITS PROPERTIES
Polarity is a physical property of compounds which relates other physical
properties such as melting and boiling points, solubility, and intermolecular interactions
between molecules. For the most part, there is a direct relationship between the
polarity of a molecule and types of polar or non-polar covalent bonds which are

52
present. In a few cases, a molecule may have polar bonds, but in a symmetrical
arrangement which then gives rise to a non-polar molecule like carbon dioxide.
Properties due to Polarity
In science particularly in chemistry, polarity is a separation of electric
charge leading to a molecule or its chemical groups having an electric dipole moment,
with a negative and positive charged end.
Molecular polarity controls or determines the strength and types
of intermolecular forces of attraction between molecules.
The easiest properties to understand regarding polarity is melting and boiling
points. The more polar a molecule is, the greater its attraction to other molecules like
it. This means that they will stick or attract together tightly even if given a lot of
energy. Ionic molecules are generally solid at room temperature. As a matter of fact,
it can take a lot of energy to melt many of them (>1000°F). Example is NaCl.
Source: http://physicalsciencetext.weebly.com/97---properties-due-to-polarity.html
Polar molecules like water are liquid at room temperature. They have a strong
attraction to each other, but not as strong as ions. Molecules that are nonpolar do not
have the attraction. The only thing that keeps them together is their size. Larger non-
polar molecules like gasoline can be a liquid at room temperatures but become a gas
very easily. Most small. nonpolar molecules (CH4) are gases for a very long period of
time. N2 becomes a liquid at -196°C (-320°F).
The magnitude of these forces is directly proportional to boiling and melting
points. In addition, molecular polarity affects solubility in polar molecules. They are
best solvated by polar solvent molecules and nonpolar molecules are best solvated by

53
nonpolar solvent molecules. The general rule of solubility is Like Dissolves Like. This
explains that polar solvent dissolve polar solute, while nonpolar dissolve
nonpolar. Water (polar) and oil (nonpolar) don’t mix and if the sum of the bond
polarities is zero, the molecule is nonpolar which means the substance is not soluble
in polar solvents like water and will be more soluble in nonpolar solvents like hexane
and it will have relatively low boiling and melting points. However, the sum of the
bond polarities is not zero, the molecule is polar. The greater the sum, the more polar
the molecule and the greater its solubility in polar solvents like water and the higher
its expected boiling and melting points.
Another way to determine if a molecule is polar or nonpolar, it is frequently
useful to look at Lewis structures. Nonpolar compounds will be symmetric, meaning all
the sides around the central atom are identical - bonded to the same element with no
unshared pairs of electrons. Notice that a tetrahedral molecule such as CCl4 is
nonpolar. Another nonpolar molecule shown below is boron trifluoride, BF3. It is a
trigonal planar molecule and all three peripheral atoms are the same.
Source: https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Map%3A_Chemistry_for_Changing_Times_
(Hill_and_McCreary)/04%3A_Chemical_Bonds/4.12%3A_Shapes_and_Properties-_Polar_and_Nonpolar_Molecules
Polar molecules are asymmetric, either containing lone pairs of electrons on a
central atom or having atoms with different electro negativities bonded. This works
well - if you can visualize or picture out the molecular geometry. To know how the
bonds are oriented in space, you must have a strong grasp of Lewis structures and
Nonpolar

54
Valence Shell Electron-Pair Repulsion Theory (VSEPR theory). Assuming you do, you
can look at the structure of each one and decide if it is polar or not - whether you know
the individual atom electronegativity. This is because you know that all bonds between
unlike elements are polar, and in these examples, it doesn't matter which direction the
dipole moment vectors are pointing in or out.
Source: https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Map%3A_Chemistry_for_Changing_Times_
(Hill_and_McCreary)/04%3A_Chemical_Bonds/4.12%3A_Shapes_and_Properties-_Polar_and_Nonpolar_Molecules
Source: http://physicalsciencetext.weebly.com/96---polar-and-non-polar-molecules.html
Polar molecules interact through dipole–dipole intermolecular
forces and hydrogen bonds. Polarity causes a number of physical properties
including surface tension, solubility, and melting and boiling points.
Nonpolar molecules are molecules that lack a charge or contain a partial
charge. They are often made up of many carbon and hydrogen atoms. Due to their
lack of charge, they do not like to interact with polar molecules and when put in solution
Polar

55
with charged or polar molecules, it will separate from them. An example is when you
mix oil and water. Oil is nonpolar and water is polar. This difference in polarity causes
oil to float on top of water rather than mix with it.
Classification
Bonds can fall between one of two extremes – being completely nonpolar or
completely polar. A completely nonpolar bond occurs when the electro negativities are
the same and therefore have a difference of zero. A completely polar bond is more
correctly called an ionic bond, and occurs when the difference between electro
negativities is large enough that one atom actually takes an electron from the other
atom. The terms "polar" and "nonpolar" are usually applied to covalent bonds, that is,
bonds where the polarity is not complete. To determine the polarity of a covalent bond
using numerical value, the difference between the electronegativity of the atoms is
used.
Bond polarity is typically divided into three groups that are loosely based on the
difference in electronegativity between the two bonded atoms.
According to the Pauling scale:
Nonpolar bonds occur when the difference in electronegativity between the two
atoms is less than 0.5
Polar bonds occur when the difference in electronegativity between the two atoms is
roughly between 0.5 and 2.0
Ionic bonds occur when the difference in electronegativity between the two atoms is
greater than 2.0
Valence Shell Electron-Pair Repulsion Theory
Valence shell electron-pair repulsion theory (VSEPR theory) allows us to predict the
molecular structure, including approximate bond angles around a central atom of a
molecule from an examination of the number of bonds and lone electron pairs in its
Lewis structure. The VSEPR model assumes that electron pairs in the valence shell
of a central atom will adopt an arrangement that lessen repulsions between these
electron pairs by maximizing the distance between them. The electrons in the valence
shell of a central atom form either bonding pairs of electrons, located mainly between

56
bonded atoms, or lone pairs. The electrostatic repulsion of these electrons is reduced
or lessen when the various regions of high electron density assume positions as far
from each other as possible.
VSEPR theory predicts the arrangement of electron pairs around each central
atom and, usually, the correct or exact arrangement of atoms in a molecule. We should
understand, however, that the theory only determines electron-pair repulsions. Other
interactions, such as nuclear-nuclear repulsions and nuclear-electron attractions, are
also involved in the final arrangement that atoms adopt in a molecular structure.
Source: https://www.mchmultimedia.com/PhysicalChemistry-help/clientstories/study-tips/a-look-into-bonding-part-1-atoms.html

57
Source: https://www.youtube.com/watch?v=40mG2rQlLpk
Relate the polarity of a molecule to its properties (S11/12PS-IIIc-16)
Activity 1: Compare Me Not
Direction: Determine the difference between polar and nonpolar molecules in terms
of their properties.
Material: Paper and pen

58
Q1. How does polarity affect physical properties?
______________________________________________________________
______________________________________________________________
Q2. How is the polarity of a molecule related to its properties?
______________________________________________________________
______________________________________________________________
Q3. Explain why nonpolar molecules usually have much lower surface tension than
polar ones.
___________________________________________________________________
_________________________________________________________
Activity 2: Think About It!
Direction: Label each of the following as polar or nonpolar molecule and explain
why.
Sample Molecules Polarity Explanation
Properties
1. Boiling point
2. Melting point
3. Solubility
4. Intermolecular
forces of
attraction
5. Surface
tension
Polar
Molecule
Nonpolar
Molecule

59
1. Propane, C3H8
2. Water, H2O
3. Methanol, CH3OH
4. Oxygen, O2
5. Hydrogen cyanide, HCN
Q1. How can you determine if the polarity (polar and nonpolar molecule) is symmetric
or asymmetric?
______________________________________________________________
______________________________________________________________
Activity 3: Describe My Shape
Direction: Given the molecular shape and geometric type of the molecules, describe
each geometric type and identify the polarity of the molecules
Molecules Geometric
Type
Description Polar or
Nonpolar?
1. 1. Linear
2. 2. Bent
3. Tetrahedral

60
4. Trigonal
pyramidal
5. Trigonal planar
Activity 4: Symmetric or Asymmetric?
Direction: Given the Lewis structure of the following molecule, identify whether the
given molecule is symmetric or asymmetric and label if it is polar or nonpolar
molecule.
LEWIS
STRUCTURE
SYMMETRIC or
ASYMMETRIC
POLARITY
(Polar/Nonpolar)
1. N2
2. C2H4
3. HBr
4. OCl2

61
5. SiCl4
Q1. Are all asymmetrical molecules polar?
___________________________________________________________________
_________________________________________________________
Q2. Is BH3 polar or nonpolar? Explain
___________________________________________________________________
_________________________________________________________
Activity 5: True or False
Direction: Label the following statements as True or False. If the statement is
false, underline the word/s that make it false and change it to make it true.
1. Boiling point, melting point, solubility and electro negativities are some of the
properties of the molecules that may affect the polarity of the molecules.
2. The term “Like Dissolves Like” explains that polar solvent dissolve polar solute,
while nonpolar dissolve nonpolar.
3. Polar molecules are symmetric, because having atoms with different electro
negativities bonded.
4. A water molecule, H2O, is a nonpolar molecule because of unequally shared
electrons with the oxygen atom spending more time with electrons than the hydrogen
atoms.
5. Molecular polarity controls or determines the strength and types of intermolecular
forces of attraction between molecules.
Reflection:
1. I learned that _________________________________________________

62
___________________________________________________________________
_________________________________________________________
2. I enjoyed most on ______________________________________________
___________________________________________________________________
_________________________________________________________
___________________________________________________________________
_________________________________________________________
References:
https://www.toppr.com/guides/chemistry/chemical-bonding-and-molecular-
structure/polarity-of-bonds/
http://chemphys.armstrong.edu/P1/polar/polarity.html
physicalsciencetext.weebly.com/97---properties-due-to-polarity.html
https://en.wikipedia.org/wiki/Chemical_polarity
http://physicalsciencetext.weebly.com/96---polar-and-non-polar-molecules.html
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textb
ook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical
_Properties_of_Matter/Atomic_and_Molecular_Properties/Molecular_Polarity

63
https://en.wikipedia.org/wiki/Chemical_polarity#Polar_molecules
https://www.youtube.com/watch?v=40mG2rQlLpk
https://opentextbc.ca/chemistry/chapter/7-6-molecular-structure-and-polarity/
https://www.mchmultimedia.com/PhysicalChemistry-help/clientstories/study-tips/a-
look-into-bonding-part-1-atoms.html
ANSWER KEY
Activity 1: COMPARE ME NOT

64
Q1. How does polarity affect physical properties?
The polarity of a molecule has a strong effect on its physical properties. Molecules
which are more polar have stronger intermolecular forces between them and have
higher boiling points as well as other different physical properties.
Q2. How is the polarity of a molecule related to its properties?
Polarity refers to the physical properties of compounds such as boiling point, melting
points, surface tension and their solubility. The polarity of bonds is caused due to the
interaction of the bonds between molecules and atoms with different electro
negativities.
Q3. Explain why nonpolar molecules usually have much lower surface tension than
polar ones.
Because the molecules aren't attracted to each other as much as in polar molecules,
these molecules are much less likely to have high surface tension.
Activity 2: THINK ABOUT IT!
Sample Molecules Polarity Explanation
1. Propane, C3H8 Nonpolar It is symmetric, with H
atoms bonded to every
side around the central
Properties
1. Boiling point
2. Melting point
3. Solubility
4. Intermolecular
forces of
attraction
5. Surface
tension
Polar
Molecule
1. High boiling
point
2. High melting
point
3. Soluble in
Polar solvent
4. Strong
intermolecular
forces of
attraction
5. High Surface
Tension
Nonpolar
Molecule
1. Low boiling
point
2. Low melting
point
3. Soluble in
non-
Polar solvent
4. Weak
intermolecular
forces of
attraction
5. Low Surface
Tension

65
atoms and has no
unshared pairs of
electrons
2. Water, H2O Polar Any molecule with lone
pairs of electrons
around the central atom
is polar.
3. Methanol, CH3OH Polar This is not symmetric.
The Nitrogen and
Hydrogen have
different
electronegativity values
creating uneven pull of
the electrons
4. Oxygen, O2 Nonpolar The molecule is
symmetric. The two
oxygen atoms pull on
the electrons by the
same value
5. Hydrogen cyanide,
HCN
Polar It is not symmetric.
(there is no hydroxyl
group -OH and there is
only one H not 3)
Q1. How can you determine if the polarity (polar and nonpolar molecule) is symmetric
or asymmetric?
Nonpolar molecules are symmetric because there is no unshared electrons while polar
molecules are asymmetric because it contain lone pairs of electrons on the central
atom or having atoms with different electronegativities bonded.
Activity 3: DESCRIBE MY SHAPE
Molecules Geometric
Type
Description Polar or
Nonpolar?
1. 1. Linear Two atoms
symmetrically
distributed around the
central atom. Results
in a bond angle of
exactly 1800
.
polar
2. 2. Bent Two atoms
symmetrical
Polar

66
central atom with a
lone pair of the central
atom. Results in a
bond angle slightly
less than 1200
3. Tetrahedral Four outer atoms
symmetrically
central atom. Forms a
regular tetrahedron.
Results in a bond
angle exactly 109.50
Nonpolar
4. Trigonal
pyramidal
Three outer atoms
symmetrically
central atom with one
lone pair on the
central atom. Results
in a bond angle
slightly less than
109.50
Polar
5. Trigonal
planar
Three atoms
symmetrically
central atom without
any lone pairs on the
central. All of the
atoms lies in the
same plane. Results
in a bond angle of
exactly 1200
Nonpolar
Activity 4: SYMMETRIC OR ASYMMETRIC?
LEWIS
STRUCTURE
SYMMETRIC or
ASYMMETRIC
POLARITY
(Polar/Nonpolar)

67
1. N2 Symmetric Nonpolar
2. C2H4 Symmetric Nonpolar
3. HBr Asymmetric Polar
4. OCl2 Asymmetric Polar
5. SiCl4 Symmetric Nonpolar
Q1. Are all asymmetrical molecules polar?
Yes, because it consists of lone pairs of electrons on a central atom or having atoms
with different electro negativities bonded.
Q2. Is BH3 polar or nonpolar? Explain
Nonpolar because it is completely symmetrical.
Activity 5: TRUE OR FALSE
1. Boiling point, melting point, solubility, surface tension and electro negativities are
some of the properties of the molecules that may affect the polarity of the molecules.
• Intermolecular forces of attraction
2. The term “Like Dissolves Like” explains that polar solvent dissolve polar solute,
while nonpolar dissolve nonpolar.

68
• True
3. Polar molecules are symmetric, because having atoms with different electro
negativities bonded.
• Asymmetric
4. A water molecule, H2O, is a nonpolar molecule because of unequally shared
electrons with the oxygen atom spending more time with electrons than the hydrogen
atoms.
• Polar molecule
5. Molecular polarity controls or determines the strength and types of intermolecular
forces of attraction between molecules.
• True
Prepared by:
SHAROLYN T. GALURA
Licerio Antiporda Sr National High School- Dalaya Annex
PHYSICAL SCIENCE
Name: ____________________________ Grade Level: _________
Date: _____________________________ Score: ______________

69
THE GENERAL TYPES OF INTERMOLECULAR FORCES
What holds multiple water molecules to each other? Why does a substance
have its distinctive phase? These are conceivably some of the questions we ignore
and fail to appreciate. Considering that fact, these learning activity sheets were
designed to grow your interest in science concepts we often disregard and learn more
about them.
By now you should be comfortable with the idea of a chemical bond. Both ionic
and covalent bonds form because atoms want to have the stable configuration of noble
gases. Example: Covalent bonds hold the hydrogen and oxygen atoms together in a
single water molecule. Break bonds and you change the chemical nature of that
substance.
In these learning activity sheets you will find out the different types of
intermolecular forces (IMF’s) that plays an unobtrusive role in all matters we use in our
daily life.
The Four General Types of intermolecular forces
1. London Dispersion Forces/ Van der Waals Dispersion Forces
2. Dipole-Dipole Interactions
3. Ion- ion Interactions
4. Hydrogen Bonding Interactions
1. London Dispersion Forces(LDF)
This type of intermolecular force is very weak and acts in short distances. It is
formed due to the attraction between the positively charged nucleus of an atom with
the negatively charged electron cloud of a nearby atom. This interaction creates an
induced dipole.

70
In addition, dispersion forces cause nonpolar substances to condense to liquids
and to freeze into solids when the temperature is lowered sufficiently. Because of the
constant motion of the electrons, an atom or molecule can develop a temporary
(instantaneous) dipole when its electrons are distributed unsymmetrically about the
nucleus.
https://www.chem.purdue.edu/gchelp/liquids/disperse.html
We could discount intermolecular interactions between gas-phase molecules
because these molecules are mostly far apart and moving rapidly relative to each
other. In the liquid phases, all molecules interact with one another. The stronger the
interaction between a molecule and a pure liquid, the greater will be the solubility of
the molecule in the liquid.
All molecules interact with each other through London dispersion forces, or
induced dipole interactions. In figure A.1, a 2-atom molecule collides with a 3-atom
molecule. The electron cloud of the first molecule repels the electron cloud of the
molecule it strikes, causing a displacement of some electron density away from the
nucleus. The nucleus is then poorly shielded by its own electrons and attracts the
electron cloud of the first molecule.
Figure A.1
Image: http://butane.chem.uiuc.edu/pshapley/genchem1/l20/1.html

71
Both molecules now have a small dipole moment that was induced by molecular
collision.
2. Dipole- Dipole Forces(DDF)
Molecules with permanent dipoles can interact with other polar molecules
through dipole-dipole interactions. Again this is electrostatic in nature. The molecular
dipole vector points towards high electron density.
Average dipole-dipole interaction is relatively weak, around 4kJ/ mol. This
interaction is effective over a very short range. The strength of dipole-dipole
interaction is inversely proportional to distance raised to the fourth power (d4
).
Reminder: Polar molecules are also referred to as “dipoles” due to their two poles.
Without dispersion forces substances would not be able to condense to
liquid and solid phase.
Visit: Want to learn more about dispersion forces?
Visit: https://www.youtube.com/watch?v=1iYKajMsYPY
Dipole-dipole interactions occur between polar molecules. This is due
to the partial positive pole and the partial negative pole of the molecule.

72
3. Ion- Dipole Forces(IDF)
When an ionic compound such as NaCl dissolves in water, the water molecules
arrange their oppositely charged dipole to be attracted to the fully charged ion, creating
a very strong attractive force called an ion-dipole force. The partial negative charge on
the water molecule is attracted to the fully charged positive sodium ion (Na+). The
partial positive charge on the water molecule is attracted to the fully charged negative
chloride ion (Cl-).
Electrostatic attractive forces that create the ionic bond in NaCl are ~10 times
stronger than a single ion-dipole force that is created between the ion and water. Only
if enough water molecules surround the ion creating many, many ion-dipole attractions
can the water molecule pull the ion away from the ionic crystal lattice, dissolving the
ionic compound.
4. Hydrogen Bonding Forces (HDF)
Visit: Want to learn more about dipole-dipole interactions?
Visit: https://www.youtube.com/watch?v=zOvnu0KYyxo
An ion-dipole interaction is the result of an electrostatic interaction
between a charged ion and a molecule that has a dipole. It is an
attractive force that is commonly found in solutions, especially ionic
compounds dissolved in polar liquids.
Visit: Want to learn more about ion -dipole interactions?
Visit: https://www.youtube.com/watch?v=1zhyHv2NJ04

73
Hydrogen that is bonded to very electronegative elements (F, O, or N) is highly
electron deficient. It acts as a Lewis acid and interacts with basic sites in other
molecules. The hydrogen bonding interaction is stronger than dipole-dipole
interactions. Again, it adds to the existing London dispersion forces to stabilize
molecules in solution.
The covalent bond that link H and oxygen together is known as coordinate
covalent bond, Oxygen bonds with H using its lone pair of electron.
Hydrogen bonding interactions are stronger than the other interactions that take
place in solution, with an energy of 5 to 30 kJ/mol for each interaction. It has some
aspects of dipole-dipole interactions and some aspects of covalent bonding. For
example, the interaction between X and H in X---H-Y is less than the sum of the radii
of the two atoms but more than their covalent bond distance.
Hydrogen bond is a very strong dipole-dipole interaction. Hydrogen bond
occurs in polar molecules containing H and any one of the highly
electronegative elements, in particular F, O, N.
Visit: Want to learn more about hydrogen bonds?
Vist : https://www.youtube.com/watch?v=RSRiywp9v9w
https://www.youtube.com/watch?v=b74-zoUz-a8
https://www.youtube.com/watch?v=b74-zoUz-a8

74
Describe general types of intermolecular forces (S11/12PS-IIIc-d-17)
Activity 1: Sticking Newspaper
This activity will give you an opportunity to investigate how intermolecular
forces affect a piece of newspaper, analyze intermolecular forces and chemical
bonding and demonstrate your knowledge of the forces at work between different
molecules.
Objective:
Investigate how intermolecular forces affect a piece of newspaper.
You need:
1. Newspaper strips
2. All purpose adhesive or contact cement(rugby)
3. Baby powder
4. A pair of scissors
Instructions:
1. Coat one side of the newspaper with all purpose adhesive and then lightly
apply baby powder to the same side.
2. Fold the newspaper in half so that the all purpose adhesive side is
touching. Notice that the paper does not stick together.

75
3. Then, holding the newspaper in the air, cut a small piece of the newspaper
off the bottom. Hold on to one piece of the paper and let the other piece
drop. Notice that the paper now sticks together.
4. Continue cutting the paper and examining what is happening before moving
on to the discussion questions.
Discussion Questions:
1. What forces are at work when the paper doesn't stick together?
______________________________________________________________
______________________________________________________________
______________________________________________________________
2. Why does cutting the paper change the forces between the molecules?
______________________________________________________________
______________________________________________________________
______________________________________________________________

76
Activity 2: Intermolecular Forces
Objective:
Determine the polarity and the strongest intermolecular force in the
molecules.
Instruction:
Indicate the strongest type of intermolecular force (LDF, DDF, HBF, or IDF)
between the molecules in the following:
Polar or Non-Polar?
Strongest
Intermolecular Force
A. CO2
B. PF3
C. HF
D. CH4
E. KBr in H2O
Reflection:
1. I learned that ______________________________________________________
___________________________________________________________________
___________________________________________________________________
2. I enjoyed most on___________________________________________________
___________________________________________________________________
___________________________________________________________________.
3. I want to learn more on ______________________________________________

77
___________________________________________________________________
___________________________________________________________________.
References
Types of Intermolecular Forces, Professor Patricia Shapley (2011)
http://butane.chem.uiuc.edu/pshapley/genchem1/l20/1.html
London Dispersion Forces, Bozeman Science ( 2013)
https://www.youtube.com/watch?v=1iYKajMsYPY
https://chem.libretexts.org/Bookshelves/General_Chemistry/Map%3A_Chemis
try_The_Central_Science_(Brown_et_al.)/11%3A_Liquids_and_Intermolecula
r_Forces/11.S%3A_Liquids_and_Intermolecular_Forces_(Summary)
Intermolecular Forces Magic Trick, FlinnScientific (2012)
http://elearning.flinnsci.com

78
Answer Key
Independent Activity 1
Discussion Question Answers:
1. None. The powder will absorb any remaining moisture and create a thin,
slippery barrier that will keep the newspaper from sticking to itself.
2. When you cut the newspaper you put intense pressure on it allowing the
rubber cement molecules at the tip of the newspaper to stick together.
Independent Activity 2
Answers: A) nonpolar, LDF; B) polar, DDF; C) polar, HBF; D) nonpolar, LDF; E)
polar,IDF

79
Prepared by:
ALDRIN GRAGEDA
Pattao National High School
PHYSICAL SCIENCE
Name: ____________________________ Grade Level: _________
Date: _____________________________ Score: ______________
Effects of Intermolecular Forces on the Properties of Substances
Imagine you just broke your favorite lamp. You have several different types of
glue to put it back together. If you choose a weaker glue, it won't take much force for

80
the lamp to fall apart again, while using a stronger glue would require a lot more force
to break that bond.
Intermolecular forces are like the glue, only instead of holding a lamp together,
intermolecular forces hold molecules together. There are strong and weak forces; the
stronger the force, the more energy is required to break those molecules apart from
each other.
So, if two molecules are only connected using van der Waals dispersion forces,
then it would require very little energy to break those molecules apart from each other.
On the other hand, if two molecules are connected using ionic bonds, it takes a whole
lot more energy to break those two apart.
In these learning activity sheets, you will learn and understand how
intermolecular forces affect the physical properties of substances.
Intermolecular Forces and Physical Properties
Stronger intermolecular forces will result in a higher physical properties such as
higher melting or boiling points, which require breaking molecules apart. Higher
intermolecular forces also leads to a higher freezing point, but since we are talking
about lowering the temperature for freezing points, we often say that lower
intermolecular forces requires lowering the temperature more.
Since a higher vapor pressure means that it is easier to vaporize a compound,
this means that lower intermolecular forces leads to a higher vapor pressure.
Viscosity
When you pour a glass of water, or fill a car with gasoline, you observe that
water and gasoline flow freely. But when you pour syrup on pancakes or add oil to a
car engine, you note that syrup and motor oil do not flow as readily. The viscosity of
a liquid is a measure of its resistance to flow. Water, gasoline, and other liquids that
flow freely have a low viscosity. Honey, syrup, motor oil, and other liquids that do not
flow freely, like those shown in Figure 1, have higher viscosities. We can measure
viscosity by measuring the rate at which a metal ball falls through a liquid (the ball falls

81
more slowly through a more viscous liquid) or by measuring the rate at which a liquid
flows through a narrow tube (more viscous liquids flow more slowly).
Figure 1. (a) Honey and (b) motor oil are examples of liquids with high viscosities; they
flow slowly. (credit a: modification of work by Scott Bauer; credit b: modification of work
by David Nagy)
The IMFs between the molecules of a liquid, the size and shape of the
molecules, and the temperature determine how easily a liquid flows. As Table 2 shows,
the more structurally complex are the molecules in a liquid and the stronger the IMFs
between them, the more difficult it is for them to move past each other and the greater
is the viscosity of the liquid. As the temperature increases, the molecules move more
rapidly and their kinetic energies are better able to overcome the forces that hold them
together; thus, the viscosity of the liquid decreases.
Substance Formula Viscosity (mPa·s)
Water H2O 0.890
mercury Hg 1.526
ethanol C2H5OH 1.074
Octane C8H18 0.508

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Substance Formula Viscosity (mPa·s)
ethylene glycol CH2(OH)CH2(OH) 16.1
Honey Variable ~2,000–10,000
motor oil Variable ~50–500
Table 2. Viscosities of Common Substances at 25 °C
Process Questions:
Put a check in the box opposite the correct answer.
1. What happens to the viscosity of a liquid when its temeperature is raised?
 The viscosity of the liquid increases.
 The viscosity of the liquid stays the same.
 The viscosity of the liquid decreases.
 The temperature of a liquid does NOT raise.
2. What is the definition of Low-viscosity?
 When a solid, quickly flows out of its container.
 When a fluid, slowly empties from its container.
 When a fluid quickly flows out of its container.
 Answer is not shown
3. Viscosity is determined mostly by what?
 Density
 The shape of the molecules of the liquid.
 Mass/Volume
 Density*Volume
Surface Tension

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A phenomenon caused by cohesive forces (intermolecular forces) between
molecules allowing liquids to create a thin film on its surface. This causes liquids to
acquire a certain shape when put on a container or dropped on surfaces.
In a container, the bulk of a liquid has a balance of intermolecular forces in all
direction. There is a net inward force on the surface since there are no liquids there.
This creates surface tension. Stronger intermolecular bonds equates to stronger
surface tension.
Among common liquids, water exhibits a distinctly high surface tension due to
strong hydrogen bonding between its molecules. As a result of this high surface
tension, the surface of water represents a relatively “tough skin” that can withstand
considerable force without breaking. A steel needle carefully placed on water will float.
Figure 2. Attractive forces result in a spherical water drop that minimizes surface area;
cohesive forces hold the sphere together; adhesive forces keep the drop attached to
the web.
Some insects, like the one shown in Figure 3, even though they are denser than water,
move on its surface because they are supported by the surface tension.
(credit photo: modification of work by “OliBac”/Flickr)

84
Figure 3. Surface tension (right) prevents this insect, a “water strider,” from sinking
into the water.
Process Questions:
1. When there are no external forces, the shape of a liquid drop is determined
by
 Surface tension of the liquid
 Density of liquid
 Viscosity of liquid
 Temperature of air only
2. What is surface tension?
 How well two liquids mix.
 The cohesion between molecules at the air-liquid surface.
Basilisk lizard or the Jesus lizard
being able to walk in water by virtue
of surface tension

85
 How heavy a liquid is.
 A definition of how much weight a liquid can carry.
Formation of meniscus
A. Concave meniscus
Occurs when there is stronger adhesive force between the container and the
liquid than the liquid’s molecules. The adhesive force overcomes the cohesive force
of the liquid. This causes the liquid to climb up the sides of the container.
B. Convex meniscus
Occurs when there is stronger cohesive force between the liquid’s molecules
than the adhesive force between the liquid and the container. This causes the liquid
to create a dome shape on its surface.
Figure 4. Differences in the relative strengths of cohesive and adhesive forces result
in different meniscus shapes for mercury (left) and water (right) in glass tubes.
(credit: Mark Ott)
Capillary Action
If you place one end of a paper towel in spilled wine, as shown in Figure 5, the
liquid wicks up the paper towel. A similar process occurs in a cloth towel when you
use it to dry off after a shower. These are examples of capillary action—when a liquid
flows within a porous material due to the attraction of the liquid molecules to the

86
surface of the material and to other liquid molecules. The adhesive forces between the
liquid and the porous material, combined with the cohesive forces within the liquid,
may be strong enough to move the liquid upward against gravity. (credit photo:
modification of work by Mark Blaser)
Figure 5. Wine wicks up a paper towel (left) because of the strong attractions
of water (and ethanol) molecules to the −OH groups on the towel’s cellulose fibers and
the strong attractions of water molecules to other water (and ethanol) molecules
(right).
Process Questions:
1. Which of the following is not an example of capillary action?
 A paper towel soaking up spilled milk
 A tree moving water up to its highest leaves
 The convex surface of mercury in a narrow glass tube
 Water climbing higher in a straw than in the glass in which it sits
2. Under what conditions does capillary action occur?
 When cohesion and adhesion are equal
 When cohesion is greater than adhesion
 When adhesion is greater than cohesion
 All of the answers are correct
Explain the effect of intermolecular forces on the properties of substances
(S11/12PS-IIId-e-19)

87
Activity 1: Measure Surface Tension with a Coin
Have you ever noticed on a rainy day how water forms droplets on a window?
Why does it do that instead of spreading out evenly over the whole surface? You might
not guess it but this property of water is also related to washing dishes and doing the
laundry. How? It all has to do with something called surface tension. Try this activity
to learn more!
Objective:
Measure how soap affects the surface tension of water by putting drops of water
on a coin.
Materials and Equipment:
• Tap water
• Dish soap
• Drinking glasses, cups, or small bowls (2)
• Spoon
• 1 cc syringes (2)
• Coin
• Paper towel or dish towel
Experimental Procedure
1. Fill in the table below with the data gathered from this activity.
Note: You can record the volume of water in either milliliters (mL) or cubic
centimeters (cc). One milliliter is equal to one cubic centimeter (1 mL = 1 cc).
Milliliters of Water Until Drop Breaks
Type of Water Trial 1 Trial 2 Trial 3 Average
Regular Water
Soapy Water
Table 1. Data table for recording the results of your experiment.

88
2. Fill one clean glass, cup, or small bowl with tap water.
3. Fill a second clean glass, cup, or small bowl with tap water. Pour in a few drops of
dish soap and mix gently with a clean spoon.
4. Insert the tip of a syringe into the glass of plain tap water.
5. Pull up on the plunger of the syringe until the water in the syringe reaches the 1.0
mL mark, as shown in Figure 3. If you get too much, just squeeze some back into the
glass by pushing down on the plunger and try again.
Figure 1. A syringe filled to the 1.0 mL mark (highlighted in red) with water.
6. Place your coin on a flat, level surface where you can easily clean up a small
amount of water, like on a kitchen counter.
7. Hold the tip of the syringe over the center of the coin. Slowly press down on
the plunger, allowing one drop of water at a time to fall onto the coin.
8. Watch the coin very carefully. The drop of water forming on top of the coin
will gradually get larger. Stop pushing on the plunger as soon as the drop
spills over the edge of the coin, as shown in Figure 2.
Figure 2. From left to right: a small drop of water starts out on the coin. Eventually it
gets big enough to reach the edges of the coin, and finally it spills over the edge.

89
9. Now, look at how much water is left in your syringe. The syringe in Figure 3
has 0.3 mL of water left. Record the value left in your syringe in table 1.
Figure 3. A syringe with 0.3 mL of water left (highlighted in red).
10. Calculate how much water you pushed out of the syringe by subtracting this
value from 1.0 mL, and record this value in your data table for "Trial 1." Use
Equation 1 to do the calculation:
Equation 1: Amount of water pushed out of syringe = 1.0 mL - amount of
water left in syringe
For example, with 0.3 mL left, that means 1.0 mL - 0.3 mL = 0.7 mL were
pushed out of the syringe.
Note: If you completely emptied the syringe and the water droplet did not
break apart, then refill the syringe and continue to add water. You will then
need to add 1.0 mL to your calculation at the end. For example, if you use
one full syringe, then empty the second syringe to 0.9 mL, then you used a
total of 1.1 mL of water.
11. Completely dry off your coin and the surrounding surface with a towel.
12. Repeat steps 4–11 two more times, for your second and third trials with tap
water. Remember to fill in your data table each time.
13. Using a new syringe, repeat steps 4–11 three times with the soapy water.
Remember to completely dry off the coin between each trial, and record all
your results in your data table.
14. Calculate an average of your three trials for the plain water and soapy water.
Do this by adding the values for the three trials and then dividing by 3.
a. For example, if your values for the plain tap water were 0.7 mL, 0.9
mL, and 0.95 mL, the average would be (0.7 + 0.9 + 0.95) ÷ 3 = 0.85 mL.
15. Make a bar graph of your results.
a. Put the type of water (plain or soapy) on the x-axis (horizontal line).

90
b. Put the average mL of water when the drop broke on the y-axis
(vertical line).
c. If you need help making a graph, try the Create a Graph website.
For help creating graphs, try this website:
National Center for Education Statistics, (n.d.). Create a Graph.
Retrieved June 2, 2009, from http://nces.ed.gov/nceskids/createagraph/
16. Based on the size of the droplets, do you think adding soap increased or
decreased the surface tension of the water?
Make it your own!
Variations:
Do you get different results depending on which side of the coin you use (heads
or tails)?
Do your results change if you use an old, dirty coin or a new, shiny coin? If you
do not have any shiny new coins, look up directions online for how you can
clean coins with vinegar.
Try mixing other things from your kitchen with water. Does dish soap give
different results from hand soap or laundry detergent? What about pouring in
something like salt or sugar?
What happens if you try the experiment with different liquids, like milk or juice?
Process Questions:
1. What is surface tension?
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
2. How is surface tension created by molecules pulling on each other?
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
3. Do you think soap will increase the surface tension of a water droplet (make the
drop bigger) or decrease the surface tension (make the drop smaller)?
___________________________________________________________________
___________________________________________________________________

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___________________________________________________________________
___________________________________________________________________
Activity 2: Measuring Viscosity
Engineers often design devices that transport fluids, use fluids for lubrication,
or operate in environments that contain fluids. Thus, engineers must understand how
fluids behave under various conditions. Understanding fluid behavior can help
engineers to select the optimal fluids to operate in devices or to design devices that
are able to successfully operate in environments that contain fluids.
Objectives:
After this activity, students should be able to:
✓ measure the viscosity of a fluid; and
✓ describe a fluid as having "high" or "low" viscosity.
Materials List:
• ruler
• stopwatch
• graduated cylinder (the taller the better)
• marble or steel ball (must be half the diameter of the cylinder or smaller, and
sink in the fluid being measured; the slower the ball sinks, the easier it is to
measure the viscosity)
• Viscosity Activity Worksheet (found at the last page of this module)
• Internet access, to research viscosities for one worksheet question
• thick, somewhat clear household fluids, such as motor oil, corn syrup,
pancake syrup, shampoo, liquid soap enough of each liquid to fill a graduated
cylinder

92
• scale, to measure the masses of graduated cylinders, with and without the
liquids
Procedure:
1. Choose a fluid to measure the viscosity.
2. Calculate the density of the fluid.
• Weigh the empty graduated cylinder.
• Fill the cylinder with fluid, and record the volume.
• Weigh the full graduated cylinder. Subtract the mass of the empty
graduated cylinder to determine the mass of the fluid.
• The density of the fluid is the mass over the volume.
Note: 1 cm3=1 ml.
3. Measure the density of the sphere.
• Measure the radius of the ball. Record as r [cm].
• Calculate the volume of the sphere:
Alternatively, place the sphere in a graduated cylinder half filled with water; the
displacement of the water is equal to the volume of the sphere.
• Weigh the sphere, and calculate the density:
4. Drop the ball into the fluid, timing the ball as it falls a measured distance.
5. Calculate the velocity of the ball falling through the fluid.
6. Calculate the viscosity of the fluid using the following equation,

93
where g is acceleration due to gravity (981 [cm/s2]). The answer should be
in units of kg/cm s, or mPa-s. For comparison, the viscosity of water is
approximately 1 mPa-s.
7. For accuracy, repeat the experiment and calculate an average viscosity.
8. Share, compare and discuss results with your classmates through video
conferencing.
Activity Extensions
Viscosity changes with temperature! Have students measure the
viscosity of a fluid at a few different temperatures and graph the viscosity (y-
axis) vs. temperature (x-axis).
Viscosity Activity Worksheet
(adopted from: Measuring Viscosity © 2011 by Regents of the University of Colorado)
https://www.teachengineering.org/activities/view/cub_surg_lesson03_activity1
1. Describe the fluid you are working with using every day descriptive vocabulary. (For
example: “I am looking at honey. It is yellow(ish) and clear(ish). It is pretty thick and
moves slowly. It feels sticky.”)
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
2. Calculate the density of the fluid using these steps:
• Weigh the empty graduated cylinder. Record its mass in grams.
Mcylinder=__________ [g]

94
• Fill the cylinder with fluid, and record the volume in cm3
. Note: 1 cm3
=1 ml.
Volfluid=__________ [cm3]
• Weigh the full graduated cylinder. Subtract the mass of the empty graduated cylinder
and record the mass of the fluid.
Mfluid=__________ [g]
• The density of the fluid is the mass over the volume. Calculate the density of the fluid.
= _________ [g/cm3]
3. Measure the density of the sphere using these steps:
• Measure the radius of the sphere. Record as r [cm].
rs = __________ [cm]
• Calculate the volume of the sphere. Either use the equation:
or place the sphere in a graduated cylinder filled with water and record its
displacement.
Vols = __________ [cm3
]
• Weigh the sphere. Record its mass.
Ms = __________ [g]
• Calculate the density of the sphere by dividing its mass by its volume.

95
= __________ [g/cm3
]
4. Measure the terminal velocity of the sphere falling through the fluid using these
steps:
• With your stopwatch ready, drop the ball into the fluid.
If the fluid is not very viscous, the ball will fall through it very fast, so be ready!
If the fluid is thick enough, then the ball will reach a constant speed.
This is the terminal velocity, the point at which the drag on the sphere by the fluid is
equal to the force of gravity.
• Measure how fast the ball falls a distance. Record the distance, and the time.
distance = __________ [cm]
time = ____________ [s]
• Calculate the velocity, which is the distance divided by the time.
Vs = __________ [cm/s]
5. Using this equation, derived from Stokes’ law, calculate the viscosity of your fluid.
Gravity is 981 cm/s2
. Be very careful to show your units and how they cancel out.
Your final answer should be in units of [g/(cm s)].
= __________ [g/(cm s)]
6. Viscosities are usually recorded in [Pa s]. To convert from [g/(cm s)] to [Pa s],
simply divide by 10:
=__________ [Pa s]
7. Using the internet, look up the viscosities of some common household fluids.
Be sure to include units. Do any of the answers surprise you?

96
Fluid Viscosity Fluid Viscosity
Example: blood 3 x 10-3 to 4 x10-3 [Pa s]
Note: In searching the internet, you may find viscosities in a variety of units. Some may be in Poise [P] or
Centipoise [cP]. 1 [cP]=.001 [Pa s]. The viscosity of water is 1 [cP]. Other fluids may have viscosity in
Stokes [St], which is the ratio of the viscosity to the density of the fluid. To convert from Stokes, multiply it
by the fluid’s density, or find another source! Hint: Search for “dynamic viscosity.”
Activity 3: Describe Me!
Objective:
• Describe the relationship of the properties of matter with intermolecular
forces of attraction.
Properties Description
Viscosity
Ex.
this is the measure a liquid’s resistance to
flow. Generally, the stronger is the IMF in the
liquid the more viscous it is.

97
Boiling
Point/Evaporation
Surface tension
Capillary action
Convex/Concave
meniscus
References
Teaching Guide for Senior High School PHYSICAL SCIENCE
Intermolecular Forces on Physical Properties, © copyright 2003-2020 Study.com
https://study.com/academy/lesson/effect-of-intermolecular-forces-on-physical-
properties
OpenStax, Chemistry. OpenStax CNX. Jun 20, 2016
http://cnx.org/contents/85abf193-2bd2-4908-8563-90b8a7ac8df6@9.311.
https://opentextbc.ca/chemistry/chapter/10-1-intermolecular-forces/
Finio, Ben. "Measuring Surface Tension of Water with a Penny." Science
Buddies, 12 Jan. 2020
https://www.sciencebuddies.org/science-fair-projects/project-
ideas/Chem_p021/chemistry/measuring-surface-tension-of-water-with-a-penny.
Accessed 4 June 2020.
Measuring Viscosity © 2011 by Regents of the University of Colorado
https://www.teachengineering.org/activities/view/cub_surg_lesson03_activity1

98
Answer Key
Vicosity Process Questions:
1. The viscosity of the liquid decreases.
2. When a fluid quickly flows out of its container.
3. The shape of the molecules of the liquid.
Surface Tension Process Questions:
1. Surface tension of the liquid
2. The cohesion between molecules at the air-liquid surface.
Capillary Action Process Questions:
1. The convex surface of mercury in a narrow glass tube
2. When adhesion is greater than cohesion
Activity No. 1
1. A phenomenon caused by cohesive forces (intermolecular forces) between
molecules allowing liquids to create a thin film on its surface.

99
2. A water molecule in the middle of a droplet gets pulled equally in all directions by
the neighboring molecules. However, a molecule at the surface of the droplet gets
pulled mostly inward by the molecules below it. This means that all the molecules
at the surface help "hold together" the droplet of water.
3. Soap is an example of a “surfactant”. This means that soaps tend to reduce the
surface tension of a liquid in which it is dissolved thus making the drop smaller.
Activity No. 2 Worksheet
Answers to questions 1-6 will vary, depending on the fluids and equipment used.
Fluid Viscosity Fluid Viscosity
Example: blood
3 x 10-3 to 4 x10-3 [Pa
S]
castor oil 0.25 to 0.5
SAE 30 motor
oil
0.25 to 0.5 [Pa S] ketchup 50 to 70 [Pa S]
maple syrup 0.15 to 0.2 [Pa S]
shortening or
lard
1,000 to 2,000 [Pa S]
milk
2 x 10-3 to 5 x10-3
[Pa S]
honey 2 to 3 [Pa S]
Activity 3.
Boiling Point- solutions with stronger intermolecular forces (IMF) have higher
boiling points than solutions with weaker intermolecular forces. The solutions with
stronger IMF holds it molecules together stronger hence making it harder for the
solution to evaporate and eventually boil.
Surface Tension- this is a phenomenon wherein a liquid creates a seemingly thin
film on its surface. The stronger the IMF, the stronger is its surface tension.

100
Capillary Action- this is the ability of fluids to rise in narrow tubes. The IMF between
the surface of the tube and the liquid allows the liquid to rise provided that the IMF
between the surface and the liquid is stronger than the cohesive forces within the
liquid.
Convex and concave meniscus - a convex meniscus is formed when the cohesive
forces within a liquid is stronger than the adhesive forces between the liquid and
the surface of the container. Concave meniscus on the other hand is the opposite
wherein the adhesive forces is stronger than the cohesive forces. The cohesive and
adhesive forces are both due to IMF.
Prepared by:
ALDRIN GRAGEDA
Pattao National High School
PHYSICAL SCIENCE
Name ________________________ Grade Level: __________________
Date: _________________________ Score: _______________________
BIOLOGICAL MACROMOLECULES
Food provides the body with the nutrients it needs to survive. Many of these
critical nutrients are biological macromolecules, or large molecules, necessary for life.
These macromolecules (polymers) are built from different combinations of smaller
organic molecules (monomers). What specific types of biological macromolecules do
living things require? What are their properties and what functions do they serve? In
this lesson, these questions will be explored.
There are four major classes of biological macromolecules (carbohydrates,
lipids, proteins and nucleic acids); each is an important cell component and performs
a wide array of functions. Carbohydrates and lipids are generally made up of carbon,
hydrogen and oxygen. Proteins and nucleic acids and some derivatives of
carbohydrates and lipids also contain nitrogen. Combined, these molecules make up

101
the majority of a cell’s dry mass (recall that water makes up the majority of its complete
mass).
CARBOHYDRATES
The term carbohydrate is derived from the French term hydrate de carbone
i.e. It is a hydrate of carbon or Cn (H2O)n.
Carbohydrates are, in fact, an essential part of our diet; grains, fruits, and
vegetables are all natural sources of carbohydrates. Carbohydrates provide energy to
the body, particularly through glucose, a simple sugar that is a component of starch
and an ingredient in many staple foods. It is made up of monomers of sugar.
Carbohydrates also have other important functions in humans, animals and plants. It
serves as precursors for many organic compounds (fats, amino acids). It is also
present as glycoproteins and glycolipids in the cell membrane and functions such
as cell growth and fertilization. Present as structural components like cellulose in
plants, exoskeleton of some insects, cell wall of microorganisms. Serves also as a
storage form of energy (glycogen) to meet the energy demands of the body.
Explain how the structure of biological macromolecules such as carbohydrates, lipids,
nuclei acid and proteins determine their properties and functions (S11/12PS-IIIe-22)
Activity 1. LET’S PICK THEM UP!
Mang Abner has a farm located at the nearby barrio. He planted a variety of
fruits and vegetables. Now that it's harvest time, let’s help Mang Abner to pick those
fruits and vegetables that are rich in carbohydrates. Write your answers on the
basket. https://www.youtube.com/watch?v=H8WJ2KENlK0

102
https://www.google.com/search?q=fruits+and+vegetables&tbm=isch&ved=2ahUKEwiui7XU0u_qAhVkzYsBHdgeBGQQ2cCegQIABAA&oq=fruits+
and+vegetables&gs_lcp=CgNpbWcQAzIHCAAQsQMQQzICCAAyAggAMgIIADICCAAyAggAMgIIADICCAAyAggAMgIIADoECAAQQzoFCAAQsQ
NQOQPWIOjEGC5uhBoAHAAeACAAdcRiAG8UJIBCTYtMS4wLjQuMZgBAKABAaoBC2d3cy13aXotaW1nwAEB&sclient=img&ei=fPEfX67dK-
Sar7wP2L2QoAY#imgrc=FOTbZ2nRvEkbGM
All carbohydrates contain carbon, hydrogen and oxygen. They may be
classified into the following:
A. Monosaccharides (simple sugars)
B. Disaccharides (simple sugars)
C. Polysaccharides (complex carbohydrates
MONOSACCHARIDES
(mono- = “one”; sacchar- =“sweet”) are simple sugars, the most common of
which is glucose. In monosaccharides, the number of carbon atoms usually ranges
from three to six. Most monosaccharide names end with the suffix –
ose.Monosaccharides or simple sugars are the basic building blocks of large
carbohydrate molecules. Monosaccharides contain two kinds of functional groups-two
or more hydroxyl groups (-OH) and a carbonyl group (C=O). Glucose is an example
of this type of sugar. It is a major carbohydrate found in plants and animals. Glucose
has many isomers. Isomers are two or more compounds that have the same molecular
formula but different arrangements of atoms.
Functional groups– two or more hydroxyl groups (-OH) and carbonyl groups
(C=O). Because they have polar, hydroxyl (-OH) groups in their molecular structure,
they are very soluble in water.

103
There are 3 classifications of monosaccharide:
1. Glucose
- The most common simple sugar in our body.
- It is also known as “blood sugar” since it is the principal sugar in the blood ,
“dextrose”, and “grape sugar” or “wine sugar” due to its abundance in grapes.
- It is also the chief source of energy for our body cells.
2. Fructose
- It is the sugar present in fruits, honey and vegetables.
- Fructose has been used as a sweetener.
- It is often called “fruit sugar”.
3. Galactose
- It is the simple sugar present in milk and peas.
Activity 2. Finding Nimo
Directions. Loop the words that are related to monosaccharides. They are written
horizontally, diagonally or vertically.
https://www.google.com/search?q=monossacharide+structure&tbm=isch&ved=2ahUKEwjl0P-Y1O_qAhUpxosBHQHxAbAQ2-
cCegQIABAA&oq=monossacharide+structure&gs_lcp=CgNpbWcQA1D3kAlYkuUJYNrpCWgAcAB4AIABAIgBAJIBAJgBAKAB
AaoBC2d3cy13aXotaW1nwAEB&sclient=img&ei=GPMfX-XkO6mMr7wPgeKHgAs

104
DISACCHARIDES
In the morning, Aaron Jay’s mother prepares his coffee; he always adds half a
teaspoon of table sugar. He remembered his TLE teacher who mentioned one time in
their classes that the sugar we use to sweeten coffee is a disaccharide. It is also called
sucrose with the molecular formula C12H22O11. He wondered how sucrose, which is
disaccharide, is formed.
A disaccharide consists of 2 monosaccharide units (similar or dissimilar) held
together by a glycosidic bond. They are crystalline, water soluble and sweet to taste.
The three most common disaccharides are:
MALTOSE
It is also called malt sugar, the least common disaccharide in nature. It is
present in germinating grain, in a small proportion in corn syrup, and forms on the
partial digestion of starch. It can be obtained when
Glucose + Glucose = Maltose

105
https://www.google.com/search?q=maltose+structure&tbm=isch&ved=2ahUKEwiA8tX3
1O_qAhUNUJQKHfVRD9IQ2-cCegQIABAA#imgrc=0kl0rZhgnEOjxM
- made up of 2 glucose molecules
LACTOSE
It is a disaccharide sugar composed of galactose and glucose is found naturally
in milk, thus so called as milk sugar. It makes up around 2-8% of milk (by weight),
although the amount varies among species and individuals, and milk with lactose also
exists. The souring of milk is due to conversion of lactose to lactic acid. Just like
sucrose, it has to be broken down into simple units to be used in the metabolic
processes of the cell. It ends up in the large intestines where bacteria proceed to
digest it.

106
https://www.google.com/search?source=univ&tbm=isch&q=sucrose+structure+and+image&sa
=X&ved=2ahUKEwjYtZi0oe_qAhUDGqYKHcSmAuIQsAR6BAgJEAE
https://www.google.com/search?q=lactose+structure+and+image&tbm=isch&ved=2ahUKEwigvd
HZoe_qAhU_xIsBHYEcA5QQ2-cCegQIABAA
Glucose + Galactose = Lactose
SUCROSE
Sucrose or table sugar is a type of sugar that is present in almost everything
we eat. It is a natural compound and one that gives us valuable energy. We are
energetic because of this. It is obtained commercially from sugarcane, sugar beet, and
other plants and used extensively as a food and sweetener. It is obtained when
Glucose + Fructose = Sucrose

107
https://www.google.com/search?q=maltose+structure
&tbm=isch&ved=2ahUKEwiA8tX31O_qAhUNUJQKHf
VRD9IQ2-cCegQIABAA#imgrc=0kl0rZhgnEOjxM
cCegQIABAA&oq=ice+cream+image&gs_lcp=CgNp
bWcQA1CHxBJYpNoSYN7eEmgAcAB4AIABAIgBA
JIBAJgBAKABAaoBC2d3cy13aXotaW1nwAEB&scli
ent=img&ei=3fsfX7b7Dsem0QTywbqwDA#imgrc=Q
CG9PWvRSnbduM
ture
e_q
cCegQIABAA&oq=beverage+image&gs_lcp=CgNpb
WcQA1D28A5YwvkOYIKDD2gAcAB4AIABAIgBAJI
BAJgBAKABAaoBC2d3cy13aXotaW1nwAEB&sclien
t=img&ei=K_0fX4_kMM-Rr7wPprag-
https://www.google.com/search?source=univ&tbm=isch&q=sucro
se+structure+and+image&sa=X&ved=2ahUKEwjYtZi0oe_qAhUD
GqYKHcSmAuIQsAR6BAgJEAE
https://www.google.com/search?q=sugars&tbm=isch&ved=2ah
UKEwjI-LTr3u_qAhUPU5QKHV6SB3wQ2-
cCegQIABAA&oq=sugars&gs_lcp=CgNpbWcQA1DFlhZY1aM
WYMykFmgAcAB4AIABAIgBAJIBAJgBAKABAaoBC2d3cy13a
XotaW1nwAEB&sclient=img&ei=Qv4fX8jPCo-
m0QTepJ7gBw#imgrc=JV0oVgybfkF-0M
Activity 3. Classify Me!
Directions: Determine the given disaccharide according to its classification. Write
your answers below the structure or the picture.
2
1
3 4
5 6

108
POLYSACCHARIDES
Polysaccharides are complex macromolecules that are made made up of
chains of monosaccharides. The bonds that form these chains are glycosidic bonds.
Three important polysaccharides, starch, glycogen, and cellulose, are composed of
glucose. Starch and glycogen serve as short-term energy stores in plants and animals,
respectively. The glucose monomers are linked by glycosidic bonds.
Common
Polysacc
haride
Properties Structure
Starch - a chain of glucose units
- serve as a source of energy for
animals and humans.
- natural polymers glucose
-what we eat from plants are
mostly made of starch.
https://www.google.com/search?q=starch+structure&tbm=is
ch&ved=2ahUKEwiy672p_-_qAhVMXJQKHZBeA10Q2-
cCegQIABAA&oq=starch+structure&gs_lcp=CgNpbWcQA1
Dg6ANY7_YDYKn9A2gAcAB4AIABAIgBAJIBAJgBAKABA
aoBC2d3cy13aXotaW1nwAEB&sclient=img&ei=UiAgX7L6
EMy40QSQvY3oBQ#imgrc=2DWaZRA80PuDlM
Cellulose - made up of repeating glucose
units.
- cannot be digested by the
body.
- commonly found in cell walls of
plants.
- the principle structure of plant
cells and fibers.
https://www.google.com/search?q=cellulose+structure&tbm
=isch&ved=2ahUKEwit1YPe0-_qAhUNzYsBHeuKBeQQ2-
cCegQIABAA&oq=cellulose+structure&gs_lcp=CgNpbWcQ
A1Ciis8FWLenzwVgiK3PBWgAcAB4AIABAIgBAJIBAJgBA
KABAaoBC2d3cy13aXotaW1nwAEB&sclient=img&ei=nfIfX-
2SE42ar7wP65WWoA4

109
Glycogen - it is what we store as we digest
starch.
- found in the muscle and liver
- it acts as an immediate source
of energy in the muscles.
- it is concentrated in the liver
and can constitute up to 10
percent of the dry weight of the
liver.
- muscle glycogen is diminished
during exercise.
https://www.google.com/search?q=glycogen+structure&tbm
=isch&ved=2ahUKEwjmm9zY__qAhUB15QKHZAgBUkQ2-
cCegQIABAA&oq=glycogen+structure&gs_lcp=CgNpbWcQ
A1Da5g1Yt4UOYNWKDmgAcAB4AIABAIgBAJIBAJgBAKA
BAaoBC2d3cy13aXotaW1nwAEB&sclient=img&ei=tSAgX6
btFIGu0wSQwZTIBA
Activity 4. Coding-Decoding
Directions. To test your knowledge on polysaccharides, using the decoder, decode the
terms given.
DECODER
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Z Y X W V U T S R Q P O N M L K J I H G F E D C B A
TERMS ANSWERS
1. HGZIXS ________________________
2. XVOOFOLHV ________________________
3. KLOBHZXXSZIRWV ________________________
4. TOBXLTVM ________________________
5. MFGIRGRLM ________________________
6. ZWSVHREVH ________________________
7. NFHXOV ________________________
8. TOBXLHRWRX ________________________
9. KOZMGH ________________________
10. OREVI ________________________

110
LIPIDS
One day, when Aaron Jay accidentally mixed oil and water, he observed that
they do not mix. He was late in his Chemistry class the following morning but he was
able to catch up the discussion of his teacher on lipids. His teacher explained that oil
and water do not mix because they do not have the same polarity. Also oils are
composed primarily of long hydrocarbon chains. Lipids are hydrophobic (water
fearing), or insoluble in water, because they are nonpolar molecules. This is because
they are hydrocarbons that include only nonpolar carbon-carbon or carbon-hydrogen
bonds. They perform many different functions in a cell. They also provide insulation
from the environment for plants and animals. For example, they help keep aquatic
birds and mammals dry because of their water-repelling nature. Lipids are also the
building blocks of many hormones and are important constituents of the plasma
membrane. It includes a wide variety of structural types which includes carboxylic
acids or fatty acids, triglycerides or neutral fats, (also called fats and oils)
phospholipids, waxes, steroids and prostaglandins. Let us look into the classes of
lipids.
A. FATS AND OILS
The most abundant of the lipids are the fat and oils also called triglycerides or
triacylglycerols. At room temperature, fats are usually solid while oil exists as liquids.
Animal fats are mixed fats containing more saturated (no double bonds) fatty acids
than unsaturated fatty acids. Remember that all saturated hydrocarbons contain only
a single bond and they are produced only by animals. Examples of animal fats are lard
and butter. Saturated hydrocarbons contain one or more double bonds. Most oils such
as vegetable oils, corn oil, and olive oil are produced by plants.
The presence of double bonds in the fatty acids lower its melting point. At room
temperature, lauric acid is solid while linoleic acid is liquid.

111
Activity 5. Build Me
Directions: Provide the structural formula and the melting point for the common fatty
acids in the table listed below. Lauric is given.
Table 1. Research on the different structure of Some Common Fatty Acids.
Common Fatty
Acids
Structural Formula Melting Point
(0
C)
Lauric CH3(CH2)10COOH 44
Myristic 53
Palmitic 63
Stearic 70
Oleic 16
Linoleic -5
Linolenic -11
Arachidonic -50
Table 2. Fatty Acid Content of Some Glycerides
Source Saturated Unsaturated Others
Myristic Palmitic Stearic Oleic Linoleic
Animal
Fat
Butter 10 29 9 27 4 31
Lard 2 30 18 41 6 5
Beef 3 32 25 38 3 2
Plant
Oil
Corn 1 10 4 34 48 4
Soybean - 7 3 25 56 9
Peanut - 7 5 60 21 7
Olive 1 6 4 83 7 -
Self-Test 1. Directions. Based from table 2 answer the following questions.
1.Which oil contains the least amount of saturated fatty acids?
__________________________________________________________

112
2.Which fat has the greatest amount of saturated fatty acids?
__________________________________________________________
3.If you need a diet that is high in saturated fatty acids, what fat/oil are you going to
use?
___________________________________________________________
4. Carbohydrates and lipids are composed of the same chemical elements, but in
different proportions. Both are used primarily as energy sources for cell metabolism.
Which type of molecule has the higher calorie content per gram? Explain your answer.
______________________________________________________________
The human body needs essential fatty acids but cannot synthesize all the fatty
acids. Hence, they must be supplied in the diet. Infants lacking these fatty acids in
their diet will lose weight and can develop eczema, an inflammatory skin condition.
Table 2, gives the amount of fatty acids in different sources. The table identifies
which source is rich in saturated fatty acids or unsaturated fatty acids.
Incidence of heart disease is believed to be influenced by high-fat diets. Studies
show that the kind of fat consumed levels of blood triglycerides and cholesterol which
may in turn, influence the risk of having a heart attack and or stroke.

113
Self-Test 2.
Can we consider fats good or bad? Explain your answer.
B.STEROIDS
Steroids, also called corticosteroids, are anti-inflammatory medicines that
quickly fight inflammation in the body.. These are lipids characterized by three
cyclohexane rings and one cyclo-pentane ring. The steroid nucleus is found in the
structure of several vitamins and hormones, drugs, poisons, bile acids and sterol
(sterol alcohol).
The most important steroid is cholesterol. It is a sterol because of the presence
of alcohol or the hydroxyl functional group. It is found mainly in animal cells although
cell membranes of plants may contain small quantities of cholesterol as well as its
major derivatives, sitosterol.

114
Cholesterol is a sterol formed in brain tissue, nerve tissue and the blood, and is
a major compound found in gallstones. An important nerve cell, myelin covers nerve
axons to help conduct the electrical impulses that make movement, sensation,
thinking, learning and remembering possible. Studies have shown that cholesterol was
found to be the most important factor in the formation of synapses, which greatly affect
our memory and learning ability. It contributes to the formation of lipid depositions on
the inner walls of blood vessels, which harden them and obstruct blood flow, this leads
to high blood pressure, heart diseases and or stroke.
Figure 9 shows the unique structure of cholesterol which consists of four linked
hydrocarbon rings forming the bulky steroid structure. There is a hydrocarbon tail
linked to the end of the steroid and a hydroxyl group linked to the other end.
Self-Test 3. Explain the role of cholesterol in eukaryotes.

115
C.PHOSPHOLIPIDS
A phospholipid is a type of lipid molecule that is the main component of the
cell membrane. Lipids are molecules that include fats, waxes, and some vitamins,
among others. Each phospholipid is made up of two fatty acids, a phosphate group
and a glycerol molecule. When many phospholipids line up, they form a double layer
that is characteristic of all cell membranes.
In association of proteins phospholipids form the structural components of
membranes and regulate membrane permeability. Phospholipids in the mitochondria
maintain the conformation of electron transport chain components and thus cellular
respiration. They participate in the absorption of fats in the intestine. They are essential
for the synthesis of different lipoproteins and thus participate in the transport of lipids.
They prevent accumulation of fats in the liver. They participate in the transport of
cholesterol and thus help in the removal of cholesterol from the body. They act as
surfactants (respiratory distress syndrome). Cephaline is an example of phophotide
that participates in the blood clotting. Another is lecithin that plays an important role in
fat metabolism in the liver. It is also a good emulsifying agent. If one fatty acid is
removed from lecithin, lysolecithin will form. Lysolecithin is a compound that causes
destruction of red blood cells and spasmodic muscle contraction. The venom of some
poisonous snakes has an enzyme that can hasten the formation of lysolecithin and
can cause fatal reactions.

116
Self-Test 4. Directions. Answer what is asked in the following statement.
___________________ 1.They are responsible for the transport of lipids.
___________________ 2. A type of lipid molecule that is the main component of the
cell membrane.
___________________3.The most abundant of the lipids and also called triglycerides.
___________________4. They are naturally occurring esters that contain long chain
carboxylic acids.
___________________5. Responsible for storing energy for later use and are found
in hormones and cell membrane components.
___________________6. The elements found in lipids.
___________________7. Give an example of an unsaturated lipid in your diet.
___________________8. A classification of lipids that are characterized by three
cyclohexane rings and one cyclopentane ring and found in several vitamins,
hormones, drugs, poisons, bile acids and sterol.
___________________ 9. An example of a phosphatide that plays an important role
in fat metabolism in the liver.
___________________10. It is the most important steroid.
PROTEINS
Proteins are the most abundant organic molecules of the living system. In
1839, Dutch chemist GJ. Mulder was first to describe proteins. They constitute about
50% of the cellular dry weight. They constitute the fundamental basis of structure and
function of life. The term protein is derived from a Greek word proteios meaning first
place.
Let us continue the story of Aaron Jay on his journey this time to the word of
proteins. From the result of his activity, he was able to know that egg white, fish, meat
and cheese are foods rich in proteins. He learned from their discussion that proteins
are found in all living cells.Proteins are present in the different parts of the body like

117
https://www.google.com/search?q=amino+acid+structure&tbm=isch&ved=2ahUKEwizrJWdpO_qAhUB6ZQKHfXYDVoQ2-cCegQIABAA
the muscle, skin, nails and others. So it means that they are the second most common
molecules found in the human body (after water) and make up about 10% to 20% of
the mass of the cell. They are made up of the elements Carbon, Hydrogen, Oxygen,
Nitrogen and Sulfur (C, H, O, N, S). So when Aaron Jay eats protein-rich foods, his
digestive system breaks the long protein chains into simpler substances called amino
acids. He learned from his Chemistry class that amino acids are the building blocks of
proteins. Of the 20 amino acids found in human protein, 11 can be synthesized by the
body and 9 have to be supplied by the foods we eat. These 9 amino acids are also
called essential amino acids.
The figure shows the structure of amino acids. An amino acid contains both amino group (-
NH2) and a carbonyl group (-COOH). All the twenty amino acids found in proteins have the
amino group and carbonyl group attached to the same carbon. Since the amino acids contain
both an acid group (COOH) and a basic group NH2, the amino acid can act either as an acid
or base in aqueous solution.

118
Activity 6. Its Research Time
Directions. Research on the different amino acids and provide the necessary
information needed in the table below. The first one is given to you.
Amino Acids Abbreviation Symbol Condition (essential,
non essential,
conditional)
1.Alanine Ala A Non essential amino
acid
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.

119
13.
14.
15.
16.
17.
18.
19.
20.
PROTEIN STRUCTURE
There are four levels of protein structure that interdependently affect the natural
conformation of a protein.
A.Primary Structure This refers to the number and
sequence of amino acids in a protein. It
describes how amino acids are joined by
peptide bonds. A peptide bond is formed
by joining the carboxyl group of one
amino acid to the amino acid of another
amino acid. The primary structure
determines the role of protein and is
critical for proper functioning. Once the

120
sequence of the amino acid is changed,
the properties of the protein are
changed.
B.Secondary Structure This refers to the coiling of the
protein chain into a α-helix structure,
formation of b sheets, or twisting into
random structures. These structures are
the results of the interactions between R
groups, H bonding or formation of -S-S-
bonds between chains. Protein
molecules are so long that they
automatically coil, fold or twist. The
resulting shape is unique for each
polypeptide in a particular medium, at a
particular PH.
C.Tertiary structure This describes the shape of the
coiled chain when it is folded or hydrated
in its natural state.
D.Quaternary structure
This involves the clustering of
several individual peptides into a final
specific shape. A variety of bonding
interactions including hydrogen bonding,
salt bridges and disulfide bonds hold the
various chains into a particular
geometry.

121
https://www.google.com/search?q=levels+of+structure+of+proteins&tbm=isch&ved=2ahUKEwjahp7Iq-_qAhVVzYsBHT12BiUQ2-
cCegQIABAA&oq=levels+of+structure+of+proteins&gs_lcp=CgNpbWcQA1Ct_fsEWMHb_ARg2uT8BGgAcAB4AIABAIgBAJIBAJgBAK
ABAaoBC2d3cy13aXotaW1nwAEB&sclient=img&ei=fsgfX9rPC9War7wPveyZqAI#imgrc=TVAK2tHffPDrpM
LEVELS OF PROTEIN
STRUCTURE
Another type of protein is the enzymes. It is known as biological catalysts. A
catalyst is a substance that increases the rate, or velocity of a chemical reaction
without itself being changed in the overall process. Enzymes are mainly globular
proteins - protein molecules where the tertiary structure has given the molecule a
generally rounded, ball shape (although perhaps a very squashed ball in some cases).
The other type of proteins (fibrous proteins) have long thin structures and are found in
tissues like muscle and hair. We aren't interested in those in this topic.
These globular proteins can be amazingly active catalysts. You are probably
familiar with the use of catalysts like manganese(IV) oxide in decomposing hydrogen
peroxide to give oxygen and water. The enzyme catalase will also do this - but at a
spectacular rate compared with inorganic catalysts.

122
One molecule of catalase can decompose almost a hundred thousand
molecules of hydrogen peroxide every second. That's very impressive!
This is a model of catalase, showing the globular structure - a bit like a
tangled mass of string:
https://www.chemguide.co.uk/organicprops/aminoacids/enzymes.html
The role of an enzyme can be compared to a lock and a key. The lock will not
open unless you use the right key. In the same manner, an enzyme works for a
specific substrate like the enzyme lactase. Its role is to break the sugar lactose into
glucose and galactose. Without enzymes, chemical reactions in the body may be too
slow to occur at normal conditions and may affect the normal functioning of the
different systems of the body.
NUCLEIC ACIDS
Aaron Jay wonders why siblings resemble each other or how a mother and her
daughter look alike. Like Aaron Jay, he and you, will discover the answer as you
explore the next lesson on nucleic acids.

123
Nucleic Acids are molecules that code for hereditary traits by controlling the
production of protein. Like proteins, nucleic acids are long chains of polymers
consisting of simpler units or monomers. It is located in the nuclei of cells. Its elemental
compositions are carbon, hydrogen, nitrogen and phosphorus.
There are two types of nucleic acids: DNA, or deoxyribonucleic acid; and RNA,
or ribonucleic acid. DNA found mainly in the cell nuclei contains the genetic information
that codes for the sequences of amino acids in proteins. RNA is found throughout the
cell and carries out the synthesis of proteins. Nucleic acids are polynucleotides and
their building blocks are nucleotides.
Nucleotides
The monomers of nucleic acids are nucleotides. Each nucleotide is formed by
3 units – PHOSPHATE, SUGAR, NITROGENOUS BASE. It is an energy rich
compound that drives metabolic processes in cells . It serves as chemical signals, key
links in cellular systems that respond to hormones and other extracellular stimuli. The
structural component of no of enzyme cofactor and metabolic intermediate.

124
Model of Nucleotide
https://www.google.com/search?q=model+of+nucleotide&tbm=isch&source=iu&ictx=1&fir=kKemlHDg4QOm0M%253A%
DNA vs. RNA
DNA, or deoxyribonucleic acid, is like a blueprint of biological guidelines that a
living organism must follow to exist and remain functional. RNA, or ribonucleic acid,
helps carry out this blueprint's guidelines. Of the two, RNA is more versatile than DNA,
capable of performing numerous, diverse tasks in an organism, but DNA is more stable
and holds more complex information for longer periods of time.
DNA versus RNA comparison chart
DNA RNA
Stands
For
DeoxyriboNucleicAcid RiboNucleicAcid.
Definition A nucleic acid that contains the
genetic instructions used in the
development and functioning of all
modern living organisms. DNA's
genes are expressed, or
manifested, through the proteins
that its nucleotides produce with
the help of RNA.
The information found in DNA
determines which traits are to be
created, activated, or deactivated,
while the various forms of RNA do
the work.
Function The blueprint of biological
guidelines that a living organism
must follow to exist and remain
Helps
carry out DNA's blueprint
guidelines. Transfers genetic code

125
functional. Medium of long-term,
stable storage and transmission of
genetic information.
needed for the creation of proteins
from the nucleus to the ribosome.
Structure Double-stranded. It has two
nucleotide strands which consist
of its phosphate group, five-carbon
sugar (the stable 2-deoxyribose),
and four nitrogen-containing
nucleobases: adenine, thymine,
cytosine, and guanine.
Single-stranded. Like DNA, RNA is
composed of its phosphate group,
five-carbon sugar (the less stable
ribose), and 4 nitrogen-containing
nucleobases: adenine, uracil (not
thymine), guanine, and cytosine.
Base
Pairing
Adenine links to thymine (A-T)
and cytosine links to guanine (C-
G).
Adenine links to uracil (A-U) and
cytosine links to guanine (C-G).
Location
.
DNA is found in the nucleus of a
cell and in mitochondria
Depending on the type of RNA,
this molecule is found in a cell's
nucleus, its cytoplasm, and its
ribosome.
Stability Deoxyribose sugar in DNA is less
reactive because of C-H bonds.
Stable in alkaline conditions. DNA
has smaller grooves, which
makes it harder for enzymes to
"attack."
Ribose sugar is more reactive
because of C-OH (hydroxyl)
bonds. Not stable in alkaline
conditions. RNA has larger
grooves, which makes it easier to
be "attacked" by enzymes.
Propagati
on
DNA is self-replicating. RNA is synthesized from DNA
when needed
Unique
Features
.
The helix geometry of DNA is of B-
Form. DNA is protected in the
nucleus, as it is tightly packed.
DNA can be damaged by
exposure to ultraviolet rays
The helix geometry of RNA is of
A-Form. RNA strands are
continually made, broken down
and reused. RNA is more
resistant to damage by Ultraviolet
rays.

126
https://www.diffen.com/difference/DNA_vs_RNA
References
Printed Materials:
Herma D. Acosta, Liza A. Alvarez, Dave G. Angeles, Ruby D. Arre, Ma. Pilar P.
Carmona, Aurelia S. Garcia, Arlen Gatpo, Judith F. Marcaida, Ma. Regaela A. Olarte,
Marivic Rosales, and Nilo G. Salazar First Edition 2015, Science - Grade 10 Learner’s
Material
Alvin A. Tabula, Module in Biomolecules,
Electronic Sources:
https://www.youtube.com/watch?v=H8WJ2KENlK0
https://www.diffen.com/difference/DNA_vs_RNA
https://www.google.com/search?q=STRUCTURE+FOR+SUCROSE&tbm=isch&ved=
2ahUKEwipguX_z-LpAhWFAKYKHciEDbIQ2-
cCegQIABAA&oq=STRUCTURE+FOR+SUCROSE&gs_lcp=CgNpbWcQAzICCAAy
BggAEAUQHjIGCAAQBRAeMgYIABAFEB4yBggAEAUQHjIGCAAQBRAeMgYIABA
FEB46BAgAEEM6BAgAEBhQ1PVuWOWob2D9sW9oAHAAeACAAYgGiAGUTJIBC
zItNi4zLjIuOC4ymAEAoAEBqgELZ3dzLXdpei1pbWc&sclient=img&ei=_wHWXumGE
IWBmAXIibaQCw#imgrc=O7tqHdLtLiesbM
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2ahUKEwiDoe_p1uLpAhWlx4sBHa6NCUwQ2-
cCegQIABAA&oq=STRUCTURE+FOR+MALTOSE&gs_lcp=CgNpbWcQAzICCAAyB
ggAEAUQHjIGCAAQBRAeUOqrA1jeswNgm7wDaABwAHgAgAG0AogB5QySAQcw

127
LjEuNS4xmAEAoAEBqgELZ3dzLXdpei1pbWc&sclient=img&ei=KAnWXoPtFKWPr7
wPrpum4AQ#imgrc=MLu3HGCqGmX8aM
https://www.slideshare.net/mobile/wcadigpub2009zs/energy-and-digestion
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&ictx=1&fir=Ux9E08J1ctimYM%253A%252CQQN5AmWiU-
cPRM%252C_&vet=1&usg=AI4_kRwRAoXoI7p2ukQs3GmUiKvYhE5ag&sa=X&ved
=2ahUKEwjS06fU2uDpAhXEL6YKHbWxAH4Q_h0wAXoECAUQBg&biw=1366&bih=
631#imgrc=Ux9E08J1ctimY
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UKEwiHiKunxejqAhUJ6ZQKHXwjBHkQ2cCegQIABAA&oq=biomacromoleculemage
s&gs_lcp=CgNpbWcQAzoECAAQQzoGCAAQBxAeOgYIABAIEB5Qm52JBFiQzYkE
YILgiQRoCHAAeACAAf8DiAHGDpIBCTAuMi40LjUtMZgBAKABAaoBC2d3cy13aXot
aW1nwAEB&sclient=img&ei=9jccX4e1FYnS0wT8xpDIBw&bih=687&biw=1508#imgr
c=da1NHKepFvWI7M&imgdii=oK5KQuZ4I0wu2M
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zrJWdpO_qAhUB6ZQKHfXYDVoQ2-cCegQIABAA
https://www.google.com/search?q=maltose+structure&tbm=isch&ved=2ahUKEwiA8t
X31O_qAhUNUJQKHfVRD9IQ2-cCegQIABAA#imgrc=0kl0rZhgnEOjxM

128
Answer Key
ACTIVITY 1.
1. Tomato
2. Acorn Squash
3. Potato
4. Sweet potato
5. Pumpkin
6. Corn
ACTIVITY 2.
1. Galactose
2. Molecules
3. Glucose
4. Fructose
5. Monosaccharides
6. Carbohydrates
7. Dextrose
8. Carbonyl
9. Hydroxyl
10. Sugar
ACTIVITY 3.
1. Maltose
2. Lactose
3. Lactose
4. Maltose
5. Sucrose
6. Sucrose

129
ACTIVITY 4
1. Starch
2. Cellulose
3. Polysaccharide
4. Glycogen
5. Nutrition
6. Adhesives
7. Muscle
8. Glycosidic
9. Plants
10. Liver
ACTIVITY 5
SELF-TEST 1
1. Soybean and Olive Oil
2. Lard
3. Olive Oil
4. Both carbohydrates and lipids serve as a source of energy but these compounds
contain different capacities for energy but storage. Each gram of carbohydrates
stores 4 calories of energy since it contains more energy per gram than
carbohydrates.

130
SELF-TEST 2
It depends. If you eat in moderation, fats are good sources of body fuel. They
are considered as good emergency food and are a sufficient energy storage system.
However, an excess quantity of fats is not good for the heart for they tend to clog
arteries and overwork the heart.
SELF-TEST 3
Cholesterol plays an important role in eukaryotes and especially abundant in cell
membranes. Small amounts of cholesterol can also be found in the membrane of some
organelles inside the cells, such as mitochondria and the endoplasmic reticulum.
SELF-TEST 4
1. Phospholipids
2. Phospholipids
3. Fats and oils
4. Fatty acids
5. Lipids
6. Carbon, Hydrogen, Oxygen
7. Corn
8. Beef
9. Steroid
10. Cholesterol

131
ACTIVITY 6
Prepared by:
IVON A. ADDATU
Tuao Vocational Technical School-Pata Annex

132
PHYSICAL SCIENCE
Name: ____________________________ Grade Level: _________
Date: _____________________________ Score: ______________
HOW CHEMICAL CHANGES TAKE PLACE
Chemical reactions occur everywhere every day. Plants use carbon dioxide and
release oxygen through photosynthesis. Vehicles engines burn fuel and give off
exhaust gases. Metal pipes rust, and marble statues corrode. Even the stomach
chemically breaks down food into the nutrients needed by the body using the natural
substances present in the stomach like hydrochloric acid.
A Chemical reaction can be better understood by considering it as a process
involving collisions between reacting particles, resulting in the breaking of some
chemical bonds of the reactants and the creation of new bonds of the products.
The behavior of the atoms, molecules, or ions that comprise the reactants is
responsible for the rates of a given chemical reaction. Collision theory is a set of
principles that states that the reacting particles can form products when they collide
with one another provided those collisions have enough kinetic energy and the correct
orientation. Particles that lack the necessary kinetic energy may collide, but the
particles will simply bounce off one another unchanged. The figure below illustrates
the difference. In the first collision, the particles bounce off one another and no
rearrangement of atoms has occurred. The second collision occurs with greater kinetic
energy, and so the bond between the two red atoms breaks. One red atom bonds with
the other molecule as one product, while the single red atom is the other product. The
first collision is called an ineffective collision, while the second collision is called an
effective collision.

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Photo
source:https://flexbooks.ck12.org/cbook/ck-12-middle-school-physical-science-flexbook 2.0/
An ineffective collision (A) is one that does not result in product formation. An
effective collision (B) is one in which chemical bonds are broken and a product is
formed.
.
The minimum energy required to initiate a reaction is called the Activation
energy (Ea). The collision theory also suggests that only particles that collide in the
correct geometric orientation will successfully form products.
The speed by which reactants are converted to products is referred to as the rate of
reaction.
A reaction that takes a long time to complete is described to have a low reaction
rate. A reaction that occurs quickly has a high reaction rate. While some reactions may
occur almost instantaneously, others may take hours, days, or even years to progress
to completion.
However, a reaction can be speeded up or slowed down by manipulating many
different factors, which include concentration and particle size of reactants,
temperature of the reaction and the presence or absence of catalyst.
Sodium reacts violently with water.
That’s what is happening in the picture.
Why does sodium have such explosive
reactions?
It is because the reactions occur so quickly.
How Fast Does It Go?
Photo
source:https://flexbooks.ck12.org/cbook/ck
-12-middle-school-physical-science-flexbook
2.0/

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Temperature
When the temperature of reactants is higher, the rate of the reaction is faster.
At higher temperatures, particles of reactants have more energy, so they move faster.
As a result, they are more likely to bump into one another and to collide with greater
force. For example, food spoils because of chemical reactions, and these reactions
occur faster at higher temperatures (see the bread on the left in the Figure). This is
why we store foods in the refrigerator or freezer (like the bread on the right in the
Figure). The lower temperature slows the rate of spoilage.
Surface Area
When a solid substance is involved in a chemical reaction, only the matter at
the surface of the solid is exposed to other reactants. If a solid has more surface area,
more of it is exposed and able to react. Therefore, increasing the surface area of solid
reactants increases the reaction rate. Look at the hammer and nails pictured in the
Figure below. Both are made of iron and will rust when the iron combines with oxygen
in the air. However, the nails have a greater surface area, so they will rust faster.
Left image: Bread after 1 month on a warm countertop. Right image: Bread after 1 month in a cold
refrigerator.
Photo source:https://flexbooks.ck12.org/cbook/ck-12-middle-school-physical-science-flexbook 2.0/

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Photo source:https://flexbooks.ck12.org/cbook/ck-12-middle-school-physical-science-flexbook 2.0/
Concentration of Reactants
Concentration is the number of particles of a substance in a given volume.
When the concentration of reactants is higher, the reaction rate is faster. At higher
concentrations, particles of reactants are crowded closer together, so they are more
likely to collide and react. Did you ever see a sign like the one in the Figure? You might
see it where someone is using a tank of pure oxygen for a breathing problem.
Combustion, or burning, is a chemical reaction in which oxygen is a reactant. A greater
concentration of oxygen in the air makes combustion more rapid if a fire starts burning.
Q: It is dangerous to smoke or use open flames when oxygen is in use. Can you
explain why?
___________________________________________________________________
___________________________________________________________________
_________________________________________________.
Photo source:https://flexbooks.ck12.org/cbook/ck-12-middle-school-physical-
science-flexbook 2.0/

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Short Quiz
Directions: Encircle the letter that you think best answers the question.
1. Which factors increase the rate of a reaction?
a. Decreasing the temperature
b. Decreasing surface area
c. Increasing concentration
d. Increasing the contact time
2. Activation energy is required to start a chemical reaction. What is activation energy?
a. The energy needed for a reaction to occur
b. The minimum amount of energy needed for a reaction to potentially occur
c. The energy added by a catalyst
d. The energy possessed by the products
3. Which of the following is NOT a reason that increasing temperature increases
reaction rate?
a. Particles move faster
b. Particles collide more often
c. Particles have more effective collisions; with Ea
d. Particles are more likely to have the correct geometry
4. Decreasing the particle size decreases the reaction rate because it
a. makes particles move faster
b. increases the likelihood of collisions with the correct geometry
c. decreases the surface area available to react
d. decreases the number of collisions
5. What happens to the rate of reaction as the reactant concentration changes?
a. As the reactant concentration increases, the rate of reaction decreases.
b. As the reactant concentration decreases, the rate of the reaction decreases.
c. When the reactant concentration changes, the rate of reaction does not
change.
d. As the reactant concentration increases, the temperature increases.

137
6. In both instances, decreasing the temperature and decreasing the reactant
concentration ultimately do the same thing when it comes to the reaction rate. What
do these changes accomplish?
a. They decrease the frequency of atomic collisions, therefore decreasing the
reaction rate.
b. They increase the frequency of atomic collisions, therefore increasing the
reaction rate.
c. The decrease of one thing increases the other, and that is why they both
decrease reaction rate.
d. Increase the amount of reactants involved in the reaction.
7. What happens to the rate of reaction as temperature decreases and why?
a. The rate decreases because there are less molecules.
b. The rate increase because molecules are faster.
c. The rate increases because molecules are closer together.
d. The rate decreases because molecules are moving slower.
For items 8-10. Choose from the following choices:
a. Concentration
b. Temperature
c. Pressure
d. Surface Area
8. A reaction will not occur in the gas supply to a Bunsen burner if it is turned on without
a match.
9. The grain dispersed in the air in a grain elevator will explode or burn if a spark or
flame is present.
10. Hospital rooms or rest homes have no smoking signs in the rooms of patients who
are receiving extra oxygen.

138
Use simple collision theory to explain the effect of concentration, temperature and
particle size on the rate of reaction (S11/12PS-IIIf-23)
Activity 1: Try More! Know More!
A. List down at least five (5) chemical reactions which you are familiar with.
1. ________________________________________________________
2. ________________________________________________________
3. ________________________________________________________
4. ________________________________________________________
5. ________________________________________________________
B. Is there anything that can be done to speed up or slow down chemical
reactions?
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
_______________________________________________

139
Activity 2: Loop a Word!
Directions: Encircle the word which corresponds the answer on the statement below.
Words appear straight across, backward, straight across, up and down, down and up,
and diagonally.
1. The number of particles of a substance in a given volume.
2. Factor that affects the rate of reaction in food spoilage.
3. The theory suggesting only particles that collide in the correct geometric
orientation will successfully form products.
4. The total area that the surface of the object occupies.
5. A type of collision that does not result in product formation
6. The minimum energy required to initiate a reaction is ________ energy.
7. A type of collision in which chemical bonds are broken and a product is
formed.
8. A chemical reaction in which oxygen is a reactant.
9. A type of reaction resulting in the breaking of some chemical bonds of the
reactants and the creation of new bonds of the products.
10.Energy that it possesses due to its motion especially during collision.

140
Activity 3: Compare Me Not!
Directions: Create analogies for the factors that affect the speed of a reaction. (e.g.
studying is like the concentration factor in the reaction rate when you increase it, the
more chances of successful and greater reaction in the future.)
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
_______________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
_______________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
_______________________________________________
Activity 4: Research Time!
The atmosphere is made of 20 percent oxygen. Explain why an increase in oxygen
in the atmosphere to 50 percent would be dangerous to living things.
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
Temperature
Surface Area
Concentration

141
__________________________________________________________________
_________________________________________
Sum Up!
1. What conditions must exist before a chemical reaction can take place?
________________________________________________________________
________________________________________________________________
_________________________________________________
2. List three (3) things that affect the reaction rate of a chemical reaction.
________________________________________________________________
________________________________________________________________
________________________________________________________________
____________________________________________
3. Name three (3) ways a reaction can be slowed down.
________________________________________________________________
________________________________________________________________
________________________________________________________________
____________________________________________
4. Why does fruit ripen more slowly in the refrigerator?
________________________________________________________________
________________________________________________________________
_________________________________________________

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Reflection
1.I learned that _____________________________________________________
_____________________________________________________________
_______________________________________________________
2.I enjoyed most on _________________________________________________
_____________________________________________________________
_________________________________________________
3.I want to learn more on ______________________________________________
_____________________________________________________________
_________________________________________________

143
References
https://www.cpalms.org/Public/PreviewResourceLesson/Preview/51001
https://flexbooks.ck12.org/cbook/ck-12-middle-school-physical-science-flexbook-
2.0/
https://www.thoughtco.com/glow-stick-rate-of-chemical-reaction-607631
https://store.csionline.org/docs/physicalExample.pdf
https://quizizz.com/admin/quiz/582a58bd0a0d754977e97359/reaction-rates#

144
Answer Key
Q: It is dangerous to smoke or use open flames when oxygen is in use. Can you
explain why?
A: Because of the higher-than-normal concentration of oxygen, the flame of
a match, lighter, or cigarette could spread quickly to other materials or even
cause an explosion
Short Quiz
1. C 2. B 3. D 4. D 5. B
6. A 7. D 8. B 9. D 10 A
Activity 1:
A. Answer varies
1. Photosynthesis
2. Rusting of iron
3. Changing color of the leaf
4. Etc….
B. Possible answer
1. Increase or decrease the amount or concentration
2. Increase or decrease the temperature
3. Increase or decrease the surface area of the reactants
4. Apply or add catalysts

145
Activity 2.
1. CONCENTRATION
2. TEMPERATURE
3. COLLISION
4. SURFACE AREA
5. INEFFECTIVE
6. ACTIVATION
7. EFFECTIVE
8. COMBUSTION
9. CHEMICAL
10.KINETIC
Activity 4:
Oxygen is needed for the chemical reaction of burning. With a greater
concentration of oxygen in the atmosphere, the reaction rate of burning forest fires
would increase.
Sum Up:
1. The reactant’s particles must come in contact with each other, and this contact
must occur in such a way that the different particles can bond with each other.
2. Temperature, surface area, and concentration
3. Decrease temperature, decrease surface area and decrease reactant
concentrations
4. Heat changes the rate of a chemical reaction; the temperature in the
refrigerator is lower
Prepared by:
JOHN DAVID B. MEDRANO
Aparri East National High School

146
PHYSICAL SCIENCE
Name: ____________________________ Grade Level: _________
Date: _____________________________ Score: ______________
CATALYST
The tunnel through this mountain provides a faster route for cars to get to the other
side of the mountain. If a chemical reaction were like a road to the other side of a
mountain, a catalyst would be like a tunnel.
What Is A Catalyst?
A catalyst is a substance that increases the rate of a chemical reaction. The
presence of a catalyst is one of several factors that influence the rate of chemical
reactions. (Other factors include the temperature, concentration, and surface area of
reactants.) A catalyst isn’t a reactant in the chemical reaction it speeds up. As a result,
it isn’t changed or used up in the reaction, so it can go on to catalyze many more
reactions.
Photo source: https://flexbooks.ck12.org/cbook/ck-12-middle-school-physical-science-flexbook-2.0/

147
Question 1: How is a catalyst like a tunnel through a mountain?
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________
How Catalysts Work
Catalysts interact with reactants so the reaction can occur by an alternate
pathway that has a lower activation energy. Activation energy is the energy needed
to start a reaction. When activation energy is lower, more reactant particles have
enough energy to react so the reaction goes faster. Many catalysts work like the one
in the Figure below. The catalyst brings the reactants together by temporarily bonding
with them. This makes it easier and quicker for the reactants to react together.
(You may visit https://youtu.be/m_9bpZep1QM for better understanding.)

148
Question 2: In the Figure above, look at the energy needed in the catalytic and
non-catalytic pathways of the reaction. How does the amount of
energy compare? How does this affect the reaction rate along each
pathway?
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
_______________________
Catalysts in Living Things
Chemical reactions constantly occur inside living things. Many of these
reactions require catalysts so they will occur quickly enough to support life. Catalysts
in living things are called enzymes. Enzymes may be extremely effective. A reaction
that takes a split second to occur with an enzyme might take many years without it!

149
More than 1000 different enzymes are necessary for human life. Many enzymes
are needed for the digestion of food. An example is amylase, which is found in the
mouth and small intestine. Amylase catalyzes the breakdown of starch to sugar. You
can see how it affects the rate of starch digestion in the Figure below
Question 3: If you chew a starchy food such as a soda cracker for a couple of
minutes, you may notice that it starts to taste slightly sweet. Why does
this happen?
___________________________________________________________
___________________________________________________________
_________________________________________

150
Self-Test
Directions: Choose the letter of your choice.
1. How does a catalyst work in speeding up a reaction?
a. by lowering the activation energy or reaction
b. by giving them more energy
c. by making them more available
d. by increasing the amount of reactant
2. The minimum amount of energy needed for colliding particles to react is called
the
a. Chemical Energy c. Activation Energy
b. Kinetic Energy d. Potential Energy
3. A substance that increases the rate of a reaction without being used up during
the reaction is called a
a. Catalyst c. reactant
b. Product d. solute
4. Catalysts permit reactions to proceed along a ___________energy path.
a. lower c. the same
b. higher d. constant
5. A catalyst increases the efficiency of collisions between reactants.
a. true c. it depends upon the reactant
b. false d. no relationship at all
6. What is the name given to a catalyst in the human body?
a. Biology c. Chemical
b. Catalyst d. Enzyme
7. When a catalyst is added to a reaction the rate of reaction ________.
a. Increases c. Does not change
b. Decreases d. Is constant
8. A catalyst is __________ in a reaction.
a. used up c. limited
b. never used up d. obtained
9. A catalyst be regenerated or used again and again
a. False
b. True
c. It depends on the amount of the reactant
d. No relationship at all
10.A catalyst changes the mechanism of the reaction
a. True
b. False

151
c. It depends on the amount of the reactant
d. No relationship at all
Define catalysts and describe how it affects reaction rate (S11/12PS-IIIf-24)
Activity 1: Crossword Puzzle
Across
2. Using amylase starch can be broken down into _____________
4. A substance that increases the rate of a chemical reaction
6. Energy needed to start a reaction
8. Catalysts in living things
9. Catalyzes the breakdown of starch to sugar
Down
1. A substance that it isn’t changed or used up in the reaction
3. The catalyst brings the ___________ together by temporarily bonding with them.
5. In human body enzymes are used to aid _____________.
7. When a catalyst is added to a reaction the rate of reaction ________.
2
1
3
4
5
6 7
8
9 10

152
10. Catalysts permit reactions to proceed along a ___________energy path.
Activity 2: Research Time!
Directions: Research reactions that take place inside the human body or that are
used in industry that require the use of a catalyst.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
_____________________________________
Activity 3: Compare Not!
Directions: Create at least three (3) analogies about catalyst. (e.g. Our coach in
basketball club is like a catalyst it increases our motivation and eagerness to
win.)
1. ____________________________________________________________
____________________________________________________________
_____________________________________________
2. ____________________________________________________________
____________________________________________________________
_____________________________________________
3. ____________________________________________________________
____________________________________________________________
_____________________________________________

153
Reflection:
1.I learned that _____________________________________________________
_____________________________________________________________
_______________________________________________________
2.I enjoyed most on __________________________________________________
_____________________________________________________________
_________________________________________________
3.I want to learn more on ______________________________________________
_____________________________________________________________
_________________________________________________

154
References
https://flexbooks.ck12.org/cbook/ck-12-middle-school-physical-science-flexbook-
2.0/section/5.28/primary/lesson/catalysts-ms-ps
https://store.csionline.org/docs/physicalExample.pdf
https://quizizz.com/admin/quiz/5e7ba44053158c001bee292a/catalysts#
https://worksheets.theteacherscorner.net/make-your-own/crossword/

155
Answer Key
QUESTION 1: How is a catalyst like a tunnel through a mountain?
Like a tunnel through a mountain, a catalyst provides a faster pathway for a
chemical reaction to occur.
QUESTION 2: In the Figure above, look at the energy needed in the catalytic and
non-catalytic pathways of the reaction. How does the amount of energy compare?
How does this affect the reaction rate along each pathway?
The catalytic pathway of the reaction requires far less energy. Therefore, the
reaction will occur faster by this pathway because more reactants will have
enough energy to react.
QUESTION 3: If you chew a starchy food such as a soda cracker for a couple of
minutes, you may notice that it starts to taste slightly sweet. Why does this happen?
The starches in the cracker start to break down to sugars with the help of the
enzyme amylase.
QUIZ TIME
1. A
2. C
3. A
4. A
5. A
6. D
7. A
8. B
9. B
10.A

156
ACTIVITY 1
1. Catalyst
2. Sugar
3. Reactants
4. Catalyst
5. Digestion
6. Activation
7. Increases
8. Enzymes
9. Amylase
10.Lower
Prepared by:

157
PHYSICAL SCIENCE
Name: ____________________________ Grade Level: _________
Date: _____________________________ Score: ______________
LIMITING REACTANT
Don’t you hate running out of cooking ingredients?
Cooking is a great example of everyday chemistry. In order to correctly follow a
recipe, a cook needs to make sure that he has plenty of all the necessary ingredients
in order to make his dish. Let us suppose that you are deciding to make some
pancakes for a large group of people. The recipe on the box indicates that the following
ingredients are needed for each batch of pancakes:
• 1 cup of pancake mix
• cup milk
• 1 egg
• 1 tablespoon vegetable oil
Now you check the pantry and the refrigerator and see
that you have the following ingredients available:
• 2 boxes of pancake mix (8 cups)
• Half gallon of milk (4 cups)
• 2 eggs
• Full bottle of vegetable oil (about 3 cups)
The question that you must ask is: How many batches of pancakes can I make? The
answer is two. Even though you have enough pancake mix, milk, and oil to make many
more batches of pancakes, you are limited by the fact that you only have two eggs. As
soon as you have made two batches of pancakes, you will be out of eggs and your
“reaction” will be complete.

158
Limiting Reactant
For a chemist, the balanced chemical equation is the recipe that must be
followed. As you have seen earlier, the Haber process is a reaction in which nitrogen
gas is combined with hydrogen gas to form ammonia. The balanced equation is shown
below.
N2(𝑔) + 3H2(𝑔) → 2NH3(𝑔)
We know that the coefficients of the balanced equation tell us the mole ratio
that is required for this reaction to occur. One mole of N2 will react with three moles of
H2 to form two moles of NH3.
Now let us suppose that a chemist is to react three moles of N2 with six moles
of H2 (see Figure below).
Photo source: https://flexbooks.ck12.org/cbook/ck-12-chemistry-flexbook-
2.0/section/12.7/primary/lesson/limiting-reactant-chem
So what happened in this reaction? The chemist started with 3 moles of N2. You
may think of this as being 3 times as much as the “recipe” (the balanced equation)
requires since the coefficient for the N2 is 1. However, the 6 moles of H2 that the
Reactants Products
Balanced equation 1 mol N2 3 mols H2 2 mols NH3
Before reaction (given) 3 mol N2 6 mols H2 0 mol NH3
After reaction 1 mol N2 0 mol H2 4 mols NH3

159
chemist started with is only two times as much as the “recipe” requires, since the
coefficient for the H2 is a 3 and 3 × 2 = 6. So the hydrogen gas will be completely used
up while there will be 1 mole of nitrogen gas left over after the reaction is complete.
Finally, the reaction will produce 4 moles of NH3 because that is also two times as
much as shown in the balanced equation. The overall reaction that occurred in words:
2N2(𝑔) + 6H2(𝑔) → 4NH3(𝑔)
All the amounts are doubled from the original balanced equation.
The limiting reactant (or limiting reagent) is the reactant that determines the
amount of product that can be formed in a chemical reaction. The reaction proceeds
until the limiting reactant is completely used up. In our example above, the H2 is the
limiting reactant. The excess reactant (or excess reagent) is the reactant that is initially
present in a greater amount than will eventually be reacted. In other words, there is
always excess reactant left over after the reaction is complete. In the above example,
the N2 is the excess reactant.
Determining the Limiting Reactant
In the real world, amounts of reactants and products are typically measured by
mass or by volume. It is first necessary to convert the given quantities of each reactant
to moles in order to identify the limiting reactant.
Sample Problem: Determining the Limiting Reactant
Silver metal reacts with sulfur to form silver sulfide according to the following balanced
equation:
2Ag(𝑠) + S(𝑠) → 𝐴𝑔2S(𝑠)
What is the limiting reactant when 50.0 g Ag is reacted with 10.0 g S?

160
Step 1: List the known quantities and plan the problem.
Known
• given: 50.0 g Ag
• given: 10.0 g S
Unknown
• limiting reactant
Use the atomic masses of Ag and S to determine the number of moles of each present.
Then, use the balanced equation to calculate the number of moles of sulfur that would
be needed to react with the number of moles of silver present. Compare this result to
the actual number of moles of sulfur present.
𝐦𝐚𝐬𝐬 (𝐠) → 𝐦𝐨𝐥𝐞
Step 2: Solve.
First, calculate the number of moles of Ag and S present:
50.0 g Ag x
1 mol Ag
107.87 g Ag
= 0.464 mol Ag
10.0 g S x
1 mol S
32.07 g S
= 0.312 mol S
Second, find the moles of S that would be required to react with all of the given Ag:
0.464 mol Ag x
1 mol S
2 mols Ag
= 0.232 mol S (required)
The amount of S actually present is 0.312 moles. The amount of S that is
required to fully react with all of the Ag is 0.232 moles. Since there is more sulfur
present than what is required to react, the sulfur is the excess reactant. Therefore,
silver is the limiting reactant.
Step 3: Think about your result.
The balanced equation indicates that the necessary mole ratio of Ag to S is 2:1.
Since there were not twice as many moles of Ag present in the original amounts, that
makes silver the limiting reactant.

161
The limiting reactant/reagent is the one that produced the least amount of products.
Condition 1: If all of the amount of silver (Ag) will be consumed, how much of the silver
sulfide (Ag2S) will be produced?
0.464 mol Ag x
1 mol Ag2S
2 mols Ag
= 0.232 mol Ag2S
Condition 2: If all of the amount of sulfur (S) will be consumed, how much of the silver
sulfide (Ag2S) will be produced?
0.312 mol S x
1 mol Ag2S
1 mol S
= 0.312 mol Ag2S
From the two conditions, which reactant produced the least amount of product? Yes,
silver is the limiting reactant since it produces lesser amount of Ag2S than sulfur.
There is a very important point to consider about the preceding problem. Even though
the mass of silver present in the reaction (50.0 g) was greater than the mass of sulfur
(10.0 g), silver was the limiting reactant. This is because chemists must always convert
to molar quantities and consider the mole ratio from the balanced chemical equation.
There is one other thing that we would like to be able to determine in a limiting reactant
problem - the quantity of the excess reactant that will be left over after the reaction is
complete. We will go back to the sample problem above to answer this question.
Sample Problem: Determining the Amount of Excess Reactant Left Over
What is the mass of excess reactant remaining when 50.0 g Ag reacts with 10.0 g S?
Step 1: List the known quantities and plan the problem.
Known
• Excess reactant = 0.312 mol S
Amount of excess reactant needed = 0.232 mol S

162
Unknown
• Mass of excess reactant remaining after the reaction = ? g
Subtract the amount (in moles) of the excess reactant that will react from the
amount that is originally present. Convert moles to grams.
Step 2: Solve.
There are 2.57 g of sulfur remaining when the reaction is complete.
Step 3: Think about your result.
There were 10.0 g of sulfur present before the reaction began. If 2.57 g of sulfur
remains after the reaction, then 7.43 g S reacted.
This is the amount of sulfur that reacted. The problem is internally consistent.
2Ag(𝑠) + S(𝑠) → 𝐴𝑔2S(𝑠)
Reactants Product
Balanced equation 2 mols Ag 1 mol S 1 mol Ag2S
Before reaction (given) 50.0 g Ag or
0.464 mol Ag
10.0g S or
0.312 mol S
0 g Ag2S
During reaction (amount of
reactants consumed and
product formed)
-0.464 mol Ag -0.232 mol S +0.232mol Ag2S
After the reaction 0 mol Ag 0.08 mol S or
2.55 g S
0.232 mol Ag2S

163
Conclusion Limiting
Reactant
Excess
Reactant
More Examples!
Consider again the reaction:
3H2(g) + N2(g) 2NH3(g)
a. If 6.60 moles H2 are made to react with 4.42 moles N2, what is the limiting reagent?
How many moles NH3 will be produced? What reagent is in excess and by how much?
Determine which reagent will produce the smallest amount of product:
Therefore, the limiting reagent is H2.
The amount of limiting reagent present at the start of the reaction determines the
theoretical yield. To determine the amount of NH3 produced, use the limiting reagent.
The excess reagent is N2. If you have 6.60 moles H2 then you will need
But you have 4.42 moles N2.
Therefore, the excess amount of N2 is 4.42 moles – 2.20 moles = 2.22 moles N2.
Reactants Product
Balanced equation 3 mols H2 1 mol N2 2 mols NH3
Before reaction (given) 6.60 mols H2 4.42 mols N2 0 mols NH3
During reaction (amount of
reactants consumed and
product formed)
-6.60 mols H2 -2.20 mols N2 + 4.40 mols NH3

164
After the reaction 0 mol H2 2.22 mols N2 4.40 mols NH3
Conclusion Limiting
Reactant
Excess
Reactant
b. If 25.5 g H2 are made to react with 64.2 g N2, what is the limiting reagent? What is
the theoretical yield in g of NH3 that will be produced? How do you determine the
limiting reagent?
i. Get the number of moles of each reactant.
ii. Calculate the number of moles of product using each reagent.
iii. The one that yields the smallest number of moles of product is the limiting reagent.
From 12.6 moles of H2,
how many moles of NH3 do
we expect to get?
From 2.29 moles of N2, how many moles of NH3 do we expect to get?
The limiting reagent is N2.
What amount of NH3 will be formed in this example?
The amount of product that can be produced is determined by the limiting reagent.
Once the limiting reagent is consumed, there is no further reaction. Hence, to calculate
the amount of NH3 produced, we use 2.29 moles N2, the limiting reagent. Therefore,
the theoretical yield is 4.58 moles NH3

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Theoretical Yield, Actual Yield, and Percent Yield
The theoretical yield is the maximum amount of product that would result if the
limiting reagent is completely consumed. It is the amount of product predicted by
stoichiometry (as shown in the above example).
The actual yield is the quantity of the desired product actually formed.
If in the example given above, only 54.0 g NH3 were produced, then the actual yield is
54.0 g; the theoretical yield is 78.0 g and the % yield is:
Determine the limiting reactant in a reaction and calculate the amount of production
formed (S11/12PS-IIIh-27)
Activity 1: Self-Test
Directions: Encircle the letter of your choice.
1. What is a limiting reactant?
a. the reactant that determines how much product can be made
b. the reactant that is in excess
c. the product that you can make the most of
d. the amount of reactants that react with each other
2. You need 2 pieces of bread, 1 tablespoon of peanut butter and 2 tablespoons
of jelly to make a sandwich. If you have 10 pieces of bread, 4 tablespoons of
peanut butter and 20 tablespoons of jelly, what is the limiting reactant?
a. Bread
b. Jelly
c. peanut butter
d. sandwich

166
3. Pretend you have a job building tricycles. If you had 100 handle bars, 150
wheels, 250 pedals, and 75 seats how many tricycles could you build?
a. 50
b. 75
c. 120
d. 125
4. In problem 3, what is the limiting reactant?
a. handle bars
b. wheels
c. pedals
d. Seats
5. In problem 3, how many pedals are left over after you have built the tricycles?
a. 0
b. 100
c. 150
d. 200
Activity 2: Identifying Limiting Ingredients
Making Ham Sandwiches!
Sandwich recipe or sandwich balance equation:
2 slices bread + 3 pieces ham + 1 piece lettuce + 4 tomato slices → one sandwich

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Ingredients in the kitchen
16 pieces bread, 18 pieces ham, 7 pieces lettuce and 16 tomato slices.
Complete the table.
Clicker Question
1. How many sandwiches can you make? ____________
2. If you follow the recipe, using only the ingredients available, how many slices
of bread are left over? _______________
3. Which of the ingredients were present in excess? ______________
4. Which of the ingredients were consumed completely in making sandwiches?
___________________
5. Which ingredient limits the number of sandwiches you can make?
_______________________________
6. Define the term limiting ingredient. ________________________________
______________________________________________________________
__________________________________________________________
Activity 3: Assembling Oreos!
You work at a factory that makes Oreo cookies. This process is usually
automated, but there has been glitch in the software that runs the cookie-assembling
machinery. Now you and your co-workers need to put the Oreos together by hand.
Bread Ham Lettuce Tomato slices Sandwiches
Initial 0
Used
Left over

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You are given two boxes: one containing stacks of chocolate wafers and one
containing stacks of the creamy fillings. The shipping supervisor shows up to your
workstation and wants to know how many Oreos you can make with the contents of
these two boxes.
To figure this out, you look at the boxes and see the following information
printed along the outsides of each box:
Box 1
CONTENTS: Chocolate Wafers
SPECIFICATIONS: Halloween Printed, 4.6 grams each
TOTAL MASS OF CONTENTS: 662.4 grams
Box 2
CONTENTS: Double Stuff Filling
SPECIFICATIONS: Orange Color, Original Flavor, 5.3 grams each
TOTAL MASS OF CONTENTS: 508.8 grams
Taking in all this information, you think back fondly to your days as a Chemistry
student and realize that you can approach this like a chemistry problem!
You decide to write the Oreo recipe like a chemical equation:
2 Wafers + 1 Filling → 1 Oreo Cookie
a. How many chocolate wafers total do you have in the box? __________
b. Considering ONLY the chocolate wafers you have, how many Oreos total could
you make? __________
c. How many orange fillings total do you have in the box? ___________
d. Considering ONLY the orange fillings you have, how many Oreos total could
you make? ______________
e. Considering all your ingredients (both wafers and fillings), how many Oreos
could you make in total? ________________

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OREO ASSEMBLY QUIZ
Directions: Answer the following and encircle the letter of your choice.
1. If you make as many Oreos as possible, what will your estimated inventories
be after all Oreos are made? Enter your responses as integers.
Oreo cookies, chocolate wafers Fillings
2. In chemistry, the reactant that runs out first is called limiting reactant. In this
Oreo cookie scenario, what is the limiting reactant?
a. Chocolate wafers
b. Fillings
c. Usable Oreo cookies
d. Damaged/lost Oreo cookies
3. In chemistry, the reactant that is left over after the limiting reactant runs out is
called excess reactant. In this Oreo cookie scenario, what is the excess
reactant?
a. Chocolate wafers
b. Fillings
c. Usable Oreo cookies
d. Damaged/lost Oreo cookies
4. Oops! In the middle of making Oreos, you knock a stack of 5 assembled Oreos
to the floor, making them unusable. You also eat 1 Oreo because, well, you're
surrounded by Oreos. You make the remaining Oreos without losing anymore.
In chemistry, the maximum amount of product that can be made from all of the
limiting reagent is called the theoretical yield. In this Oreo cookie scenario,
what is the theoretical yield?
a. 66 Oreos
b. 72 Oreos
c. 96 Oreos
d. 144 Oreos

170
5. In chemistry, the actual amount product made and measured after a reaction is
called the actual yield. In this Oreo cookie scenario, what is the actual yield?
Here is a summary of your data:
Oreo Assembly “Equation”: 2 Wafers + 1 Filling → 1 Oreo Cookie
Starting Inventory: 144 wafers and 96 fillings
Damaged/Lost Oreos: 5 broken and 1 eaten
a. 66 Oreos
b. 72 Oreos
c. 96 Oreos
d. 144 Oreos
6. In chemistry, the percent yield is defined as
Percent yield = [(actual yield) / (theoretical yield)] x 100
In this Oreo cookie scenario, what is the percent yield?
Oreo Assembly “Equation”: 2 Wafers + 1 Filling → 1 Oreo Cookie
Starting Inventory: 144 wafers and 96 fillings
Damaged/Lost Oreos: 5 broken and 1 eaten
a. 68%.
b. 75%.
c. 92%.
d. 94%
7. The shipping supervisor returns to your station. When she asks about your
Oreo production, you report to her:
a. I made 72 Oreos, which is 100% of expected production.
b. I made 72 Oreos, which is 75% of expected production.
c. I made 66 Oreos, which is 92% of expected production.
d. I made 66 Oreos, which is 68% of expected production

171
Activity 4: Problem Solving!
Silver metal reacts with sulfur to form silver sulfide according to the following reaction:
2Ag (s) + S(s) Ag2S (s)
a. Identify the limiting reagent if 50.0 g Ag reacts with 10.0 g S.
b. What is the theoretical yield in g of Ag2S produced from the reaction?
c. What is the amount in g of the excess reactant expected to remain after the
reaction?
d. When the reaction occurred, the amount of Ag2S obtained was 45.0 g. What
is the percent yield of the reaction?

172
Reflection
1. I learned that ____________________________________________
_______________________________________________________
_______________________________________________________
2. I enjoyed most on ________________________________________
_______________________________________________________
_______________________________________________________
3. I want to learn more on ____________________________________
_______________________________________________________
_______________________________________________________

173
References:
Bain, Rachel. “Limiting Reagents – Chemistry Activities.” Pressbooks, 2020,
wisc.pb.unizin.org/chemactivities/chapter/limiting-reagents.
Costello, Collin. “Limiting Reactants - Quiz.” Quizziz, 2016,
quizizz.com/admin/quiz/57168a41333df5fa5aee8b84/limiting-reactants.
Foundation, CK-12. “12 Foundation.” CK, flexbooks.ck12.org/cbook/ck-12-chemistry-
flexbook-2.0/section/12.7/primary/lesson/limiting-reactant-chem.
“Limiting Reactant: Reaction of Mg with HCl Student Activity.” Chemdemos, 2012,
chemdemos.uoregon.edu/demos/Limiting-Reactant-Reaction-of-Mg-with-HCl-
Student-Activity.
“Mass Relationships in Chemical Reactions.” Teaching Guide for Senior High School
General Chemistry 1, 4th Floor, Commission on Higher Education, C.P. Garcia Ave.,
Diliman, Quezon City, Commission on Higher Education, 2016, pp. 100–103.

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Answer Key
ACTIVITY 1
1. A
2. C
3. A
4. B
5. C
ACTIVITY 2
1. 4
2. 8
3. Bread, Ham, Lettuce
4. Tomato slices
5. Tomato slices
6. An ingredient that limits the amount of product to be produced out of the
raw materials used.
ACTIVITY 3
1. 72- Oreo cookies, 0- chocolate wafers, 24- fillings
2. A
3. B
4. B
5. A
6. C
7. C
Bread Ham Lettuce Tomato slices Sandwiches
Initial 16 18 7 16 0
Used 8 12 4 16 4
Left over 8 6 3 0

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ACTIVITY 4
a. Ag
b. 57 g
c. 3 g
d. 79 %
Prepared by:

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PHYSICAL SCIENCE
Name: ____________________________Grade Level: _________
Date: _____________________________Score:______________
ENERGY SOURCES
• Why do we need energy?
• What do we mean by renewable and non-renewable energy sources?
• What are some examples of renewable and non-renewable energy?
• How can we harness energy from different sources?
• What might be some drawbacks to using alternative energy resources?
• What would happen if we ran out of all energy resources? Could that
ever happen?
Probing Questions You Need to Think!
Identify what energy you can get from the sources
presented in each picture and guess if it is renewable
or non-renewable energy?
EXPLORE!!
!
1 2 3
5
4

177
WHAT IS ENERGY?
Matter is made up of invisibly small particles, occupies space, has mass, and
exhibits gravitational attraction. Energy, on the other hand, possesses none of these
characteristics. Evidence of energy is everywhere. All you need to do is look for
motion, heat, and light.
The nature of energy is very complex, but it is best described by these
characteristics:
• energy is the ability to do work,
• work is the application of a force through a distance (e.g., carrying yourself
and a loaded back pack up a mountain trail),
• force is that which can put matter into motion or stop it if it is already moving (
e.g. , you are stopped at a stop sign and the car behind you doesn't see you stop, and
can't stop before colliding with your rear bumper, pushing you into the intersection),
and
• motion is a change in distance or direction with time (e.g., making a right hand
turn).
1. _______________________________ - _____________________________
2. _______________________________ - _____________________________
3. _______________________________ - _____________________________
4. _______________________________ - _____________________________
5. _______________________________ - _____________________________
MY ANSWERS...

178
Energy can be possessed by an object in two different ways, kinetic energy and
potential energy. If this energy is due to the fact that matter is moving or is in use, it is
called kinetic energy. Kinetic energy (KE) of an object is the energy that it possesses
due to its motion. It is defined as the work needed to accelerate a body of a given
mass from rest to its stated velocity. If it is due to the position, structure of matter, or
composition, it is called potential energy. Potential energy is stored energy.
Types of Energy Sources
Humans need energy for just about any type of function they perform. Houses
must be heated; energy is required for industry and agriculture and even within our
own bodies a constant flow of energy takes place. All processes that provide us with
the luxuries of everyday lives require energy generation. This is an industrial process
that can be performed using various sources. These sources can be either renewable
or non-renewable. Renewable energy sources are replaced in time and will therefore
not run out easily. However, non-renewable energy sources are threatening to run out
if our standard of usage becomes too high.
Different Sources of Energy
A. Fossil Fuels
Fossil fuels consist of deposits of once living organisms. The organic
matter takes centuries to form. Fossil fuels principally consist of carbon and
hydrogen bonds. There are three types of fossil fuels which can provides
energy; coal, oil and natural gas.
https://www.lenntech.com/greenhouse-effect/fossil-fuels.htm

179
Coal is a solid fossil fuel formed over millions of years by decay of land
vegetation. When layers are compacted and heated over time, deposits are turned into
coal. Coal is quite abundant compared to the other two fossil fuels. Analysts sometimes
predict that worldwide coal use will increase as oil supplies become scarcer. Current
coal supplies could last for 200 years or more. Coal is usually extracted in mines. Since
the middle of the 20th century, coal use has doubled. Since 1996 its application is
declining again. Many developing countries, like the Philippines, depend on coal for
energy provision because they cannot afford oil or natural gas. China and India are
major users of coal for energy provision.
Oil is a liquid fossil fuel that is formed from the remains of marine
microorganisms deposited on the sea floor. After millions of years the deposits end up
in rock and sediment where oil is trapped in small spaces. It can be extracted by large
drilling platforms. Oil is the most widely used fossil fuel. Crude oil consists of many
different organic compounds which are transformed to products in a refining process.
It is applied in cars, jets, roads and roofs and many other. Oil cannot be found
everywhere on earth and consequentially, there have been wars on oil supplies. A
well-known example is the Gulf War of 1991.
Natural gas is a gaseous fossil fuel that is versatile, abundant and relatively
clean compared to coal and oil. Like oil, it is formed from the remains of marine
microorganisms. It is a relatively new type of energy source. Since 1999, more coal
was used than natural gas. Natural gas has now overtaken coal in developed
countries. However, people are afraid that like oil, natural gas supplies will run out.
Some scientists have even predicted this might happen by the middle or end of the
21st
century. Natural gas mainly consists of methane (CH4). It is highly compressed in
small volumes at large depths in the earth. Like oil, it is brought to the surface by
drilling. Natural gas reserves are more evenly distributed around the globe than oil
supplies.
How is energy harnessed?
Energy gained from burning fossil fuels is converted to electricity and heat in
commercial power plants. When fossil fuels are burned carbon and hydrogen react
with oxygen in air to carbon dioxide (CO2) and water (H2O). During this reaction heat
is released which further amplifies the reaction. Electricity is generated by transforming

180
mechanical energy (heat) to electrical energy in a turbine or generator. Power plants
are very expensive to build, but once they are present efficiency in converting fuel to
energy is very high. Most of the time more electricity is created than is actually needed,
because electricity cannot be stored. Electricity demands vary throughout the year and
provision must meet the peak load, which means the highest possible demand within
a year. If demands significantly exceed a power plant's capacity to generate energy
this may cause temporary blackouts.
Describe how energy is harnessed from different sources:
a. Fossil Fuels
b. Biogas
c. Geothermal
d. Hydrothermal
e. Batteries
f. Solar Cells
g. Biomass
Activity 1: Complete Me!
Directions: Complete the process
How Fossil Fuels Work?
Coal is crushed to a fine dust and burnt. Oil and gas can be burned
directly. Complete the process below.
Burn fuel--------> heat water to make steam---- -------> steam turns turbine-
-----------> turbine turns generator--------- ------> electrical power

181
B. Biogas
What is biogas energy?
Biogas is produced via a process called Anaerobic Digestion (AD), which
results in the production of numerous gases that can then be burnt to produce energy.
Anaerobic digestion is the breakdown of various plant and animal material (known as
biomass) by bacteria in an oxygen-free environment. For example, the waste plant
material is sealed in an airtight container, then bacteria is added, which is encouraged
to multiply and grow, releasing methane and other gases as the by-product of the
process. In addition, there are other by-products produced in the process which are
rich in nutrients and can be used as fertilizer. The inputs in the process can be any
number of biomass materials including any of the following: food waste, energy crops,
crop residues, slurry and manure. In practice the process can take on waste from
households, supermarkets and industry, therefore reducing the waste that goes to
landfill.
The two major gases that make up biogas are methane (CH4), which accounts
for about 60%-70% of the total and also carbon dioxide (CO2) which accounts for 30%-
40%. Small traces of other gases can be found. Overall the way biogas is composed
depends on the inputs or feedstock that goes into the AD process. In industry, biogas
https://dicoagroecologie.fr/en/encyclopedia/anaerobic-digestion-on-farms/

182
can be enhanced to filter out pure methane and removing other gases, which then
becomes biomethane.
Conversion to Electricity
Theoretically, biogas can be converted directly into electricity by using a fuel
cell. However, this process requires very clean gas and expensive fuel cells.
Therefore, this option is still a matter for research and is not currently a practical option.
The conversion of biogas to electric power by a generator set is much more practical.
In contrast to natural gas, biogas is characterized by a high knock resistance and
hence can be used in combustion motors with high compression rates.
Activity 2: Creating Biogas
Directions: Answer the following questions
1. What are the main byproducts produced by the acid forming bacteria during
the initial digestion phase?
a. Water and methane
b. Carbon dioxide and organic acids
c. Struvite and hydrogen sulfide
d. Water and completely digested sludge
2. What best describes methane forming bacteria in an anaerobic digester?
a. Sensitive to environment and environmental changes
b. Fast growing organisms
c. Produce biogas at very low pH
d. They work best in the presence of oxygen
3. What conditions must be present in a digester for an aerobic digestion to
happen?
4. How can biogas be converted into electricity?

183
5. True or False: Anaerobic digestion is the breakdown of various plant and
animal material (known as biomass) by bacteria in an oxygen-free
environment.
C. Geothermal Energy
Hot rocks underground heat water to produce steam. We drill holes down
to the hot region; steam comes up, is purified and used to drive turbines, which drive
electric generators. There may be natural "groundwater" in the hot rocks anyway, or
we may need to drill more holes and pump water down to them.
Geothermal energy is produced by the heat of Earth’s molten interior. This
energy is harnessed to generate electricity when water is injected deep underground
and returns as steam (or hot water, which is later converted to steam) to drive a turbine
on an electric power generator. Moderate- to low-temperature geothermal resources
are also used to heat buildings directly and to provide space heating through district
heating systems in which heat is distributed to residences and commercial buildings
from a central source.

184
Activity 2: Power Essay
..........GEOPower Questions
1. Where does geothermal energy come from?
______________________________________________________________
______________________________________________________________
______________________________________________________________
______
2. What makes geothermal energy a good alternative source of electric power?
______________________________________________________________
______________________________________________________________
______________________________________________________________
______
3. What is one drawback of drilling geothermal wells?
______________________________________________________________
______________________________________________________________
______________________________________________________________
_____
D. Hydrothermal Energy
Hydrothermal energy refers to the heat obtained from hot water from
hydrothermal vents or seawater in contact with hot rock beds.
Hot water from hydrothermal vents is collected into a heat exchanger. The heat
from the water is transferred to another fluid (e.g. isobutene) which evaporates and
drives the turbines to generate electricity.
Hydrothermal vents are formed by seawater that percolates through fissures in
the ocean crust in regions where the Earth’s tectonic plates are spreading or
colliding. The cold sea water is heated by hot magma and then emanates from vents
in the seafloor. Water issuing from hydrothermal vents may reach temperatures of over
700° F. The water does not boil because of the extreme pressure at the ocean depths

185
where the vents are located. Hydrothermal vents are recognized as rich sources of
thermal energy. The hot water flowing from some vents contains thermal power of up
to 60 MW. The thermal energy contained in hydrothermal vents make them potential
sources for the generation of electric energy.
A thermal-to-electric conversion system can produce power to enable remote
sea sensors, recharge autonomous underwater vehicles, and facilitate a variety of
deep-sea activities. Development of a power system for this application is challenging
because the environment is extremely corrosive, and mineral precipitation and
biological activity can obstruct critical surfaces. The system must operate reliably for
long time periods without maintenance. Another challenge is that hydrothermal vents
are found in ocean depths of 1500 m or more.

186
E. Batteries
Batteries are also called electrochemical cells. They are devices that store and
convert chemical energy into electrical energy. They can be disposable or
rechargeable. The energy from batteries comes from a chemical reaction (e.g. redox
reaction between and to form).
When a battery is connected to an external circuit, electrolytes move within the
battery, and chemical reactions are completed at the two terminals of the battery. The
flow of electrons in the reactions generates the current (flowing charges) and delivers
electricity to the external circuit.
There are three main components of a battery: two terminals made of different
chemicals (typically metals), the anode and the cathode; and the electrolyte, which
separates these terminals. The electrolyte is a chemical medium that allows the flow
of electrical charge between the cathode and anode. When a device is connected to
a battery — a light bulb or an electric circuit — chemical reactions occur on the
electrodes that create a flow of electrical energy to the device.
More specifically: during a discharge of electricity, the chemical on the anode
releases electrons to the negative terminal and ions in the electrolyte through what’s

187
called an oxidation reaction. Meanwhile, at the positive terminal, the cathode accepts
electrons, completing the circuit for the flow of electrons. The electrolyte is there to put
the different chemicals of the anode and cathode into contact with one another, in a
way that the chemical potential can equilibrate from one terminal to the other,
converting stored chemical energy into useful electrical energy. “The ions transport
current through the electrolyte while the electrons flow in the external circuit, and that’s
what generates an electric current.”
If the battery is disposable, it will produce electricity until it runs out of reactants
(same chemical potential on both electrodes). These batteries only work in one
direction, transforming chemical energy to electrical energy. But in other types of
batteries, the reaction can be reversed. Rechargeable batteries (like the kind in your
cellphone or in your car) are designed so that electrical energy from an outside source
(the charger that you plug into the wall or the dynamo in your car) can be applied to
the chemical system, and reverse its operation, restoring the battery’s charge.
Activity 4: Simple Circuit
Directions: Completing the Circuit Worksheet
1. Draw two possible ways for the light bulb to glow on the space provided below.
2. What do you need to do to light up a bulb?
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
__________________
3. Describe the transformations of energy that occur in the circuit.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
________________________________________________

188
F. Solar Cells
Why is daytime brighter and warmer than night-time? The answer is simple: solar
energy. Solar energy is simply the light and heat that come from the sun. People can
harness the sun's energy using solar cells or Photovoltaic cells.
Solar Cells or Photovoltaic Cells. A photovoltaic cell absorbs light and converts it
directly into electricity. A group of photovoltaic cells is known as a solar panel.
https://archive.epa.gov/climatechange/kids/solutions/technologies/solar.html
How do Solar Cells work?
A solar cell is a sandwich of n-type silicon (blue) and p-type silicon (red). It
generates electricity by using sunlight to make electrons hop across the junction
between the different flavors of silicon:

189
When sunlight shines on the cell, photons (light particles) bombard the upper
surface.
1. The photons (yellow blobs) carry
their energy down through the
cell.
2. The photons give up their energy
to electrons (green blobs) in the
lower, p-type layer.
3. The electrons use this energy to
jump across the barrier into the
upper, n-type layer and escape
out into the circuit.
4. Flowing around the circuit, the
electrons make the lamp light.
Activity 5: Solar Electric System
Directions: In a tabular form, lists down the advantages and disadvantages of using
solar electricity system
ADVANTAGES DISADVANTAGES
G. Biomass
Biomass refers to the organic matter from living organisms and often refers to
plants or plant-based materials that can be converted to energy. It is the oldest source
of energy known to man.

190
The biomass is burned to generate heat. The heat produced can be directly
used to do daily chores such as cooking.
Electricity may also be generated from biomass. The components of biomass
are burned in a boiler. The generated heat is used to produce steam which drives the
turbines to generate electricity.
….How does it work???
Plant and animal waste is used to produce fuels such as methanol, natural gas,
and oil. We can use rubbish, animal manure, woodchips, seaweed, corn stalks and
other wastes.
Sugar cane is harvested and taken to a mill, where it is crushed to extract the
juice. The juice is used to make sugar, whilst the left-over pulp, called "bagasse" can
be burned in a power station.
Other solid wastes, can be burned to provide heat, or used to make steam for
a power station.
Process:
Burn fuel-------> heat water to make steam---------> steam turns turbine----------->
turbine turns generator------------> electrical power sent around the country
Reflection
1. I learned that __________________________________________________
_____________________________________________________________
_______________________________________________________
2. I enjoyed most on ______________________________________________
_____________________________________________________________
_________________________________________________
_____________________________________________________________
_________________________________________________

191
References
McKinney, M.L. and Schoch, R.M., Environmental Science, Systems and Solutions.
Third edition, University of Tennessee, Knoxville USA 2003
www.digitaljournal.com/tech-and-science/technology/geothermal-energy-how-we-
harness-this-energy-source-part-2/article/484581
https://www.nrel.gov/docs/gen/fy01/30927.pdf
https://www.lenntech.com/greenhouse-effect/fossil-fuels.htm
https://www.thegreenage.co.uk/tech/biogas-energy/

192
Answer Key
1. Natural gas - Non-renewable
2. Oil – Non-renewable
3. Solar Energy – Renewable
4. Coal – Non-renewable
5. Wind Energy - Renewable
1. B
2. A
3. Lack of oxygen
4. Biogas can be converted directly into electricity by using a fuel cell.
5. True
How Fossil Fuels Work?
Burn fuel------------------> heat water to make steam------------------> steam turns
turbine------------------>turbine turns generator------------------->electrical power
sent around the country
ACTIVITY 1: COMPLETE E!
EXPLORE!!
!
Activity 2:
Creating Biogas

193
1. Where does geothermal energy come from? (from deep inside Earth)
2. What makes geothermal energy a good alternative source of electric power?
(Geothermal energy generates electricity around the clock and does not
produce significant greenhouse gas emissions.)
3. What is one drawback of drilling geothermal wells? (You can’t drill just
anywhere for Earth heat; finding and trapping geothermal steam can be tricky
and costly.)
4. Why is geothermal energy not always a renewable energy source?
(Geothermal reservoirs are not inexhaustible; if not properly managed over
time, a geothermal resource may run out of steam.)
Completing the Circuit Worksheet
1. Draw two possible ways for the light bulb to glow on the space provided below.
2. What do you need to do to light up a bulb?
Light the bulb using two wires. Attach one wire to the negative end of the battery
and wrap the other end of the same wire around the base of the bulb. Attach the other
wire to the positive end of the battery with electrical tape and to the base of the bulb,
completing the circuit and lighting the bulb
3. Describe the transformations of energy that occur in the circuit.
When a battery is connected to an external circuit, electrolytes move within the
battery, and chemical reactions are completed at the two terminals of the battery. The
flow of electrons in the reactions generates the current (flowing charges) and delivers
electricity to the external circuit.
ACTIVITY 3: POWER ESSAY!
Activity 4: Simple Circuits:

194
Prepared by:
JOLLY MAR D. CASTANEDA
Baggao National Agricultural School- Sta Margarita Annex
Activity 5: In a tabular form, lists down the advantages and
disadvantages of using solar electricity system.

195
PHYSICAL SCIENCE
Name: ______________________________________Grade Level: _________
Date: ____________________________________ Score:______________
Practical Application Of Chemistry
Cleaning products play an essential role in our daily lives at home, in school
and in the office. By safely and effectively removing soils, germs and other
contaminants, they prevent the spread of infectious diseases and control allergens,
such as dust and mold, helping us to stay healthy. Cleaning products also enable us
to care for our homes and possessions.
Chemicals used for cleaning and in cleaning products, such as laundry
detergents, bleaches, dishwashing products and other household cleaners, help
improve cleaning efficiency, making homes, offices and other environments both
easier to clean and more hygienic.
How do cleaning materials actually remove dirt? Can ordinary soaps use to
clean toilets bowls and sinks? Why would muriatic acid work better in getting rid of
heavy dirt?
People use soap in the same way to clean their skin. How does soap remove
dirt from the body? Why can people not just use a detergent instead? Are they
completely safe for human use? These questions will be answered in this lesson,
which explains the basic chemistry behind common cleaning products along with
their safety and health consideration.

196
From product labels, identify the active ingredient(s) of cleaning products used at
home (S11/12PS-IIIi-j-31)
Activity 1: Chemistry Behind Common Cleaning Materials
Directions: Answer the give questions
Question 1.
Go and find a commercial product that are available in your home and read the labels
to identify the properties of chemical ingredients. Identify the different component of
different commercial products such as detergent, soap, muriatic acid and disinfectant
and give the function of each product.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________
Question 2
What are the active and inert component of common cleaning products?
__________________________________________________________________________________
__________________________________________________________________________________
_______________________________________________________________________________

197
Activity 2: Common Active and Inert Components of Cleaning Products
Directions: Fill in the box!
Commercial
Product
Active Ingredient(s) Inactive Ingredients
Detergent Ex. surfactant Ex. Bleaching agents: sodium percarbonate, or
sodium perborate
Soap
Muriatic Acid
Disinfectants
The active ingredients is the component of a product which, regardless of quantity,
directly enables it to serves its purpose.
The inert ingredients refers to all the other substances in a product. An inert ingredients
does not affect the action of the active ingredient.
The first one is given to help you.

198
Activity 3: Stop, Look and Protect
Safety Measures for Some Commercial Products
Product Possible Risks Safety Measures
Detergent Ex. Eye irritant Ex. Wear hand gloves with
people sensitive to skin.
Soap
Muriatic acid
Disinfectants
Various chemicals have detrimental effects on human health. Some people may be
allergic to certain active and inactive (or inert) ingredients. It is therefore important
to check the ingredients of the products before making purchases. The first one is
given to help you.

199
Activity 4: Surveying the House
Cleaning Materials/
Personal Care Product
General Classification
(Soap, detergent,
disinfectant)
Specific Classification
(Applicable for disinfectants:
alcohol, aldehyde, oxidizing
agent, acid, base, halogen-
based compound)
Betadine Disinfectant Halogen-based compound
Conduct a survey of common examples of cleaning materials or personal care
products available at your home. List as many as possible and classify them
accordingly by completing the table below. The first one is given to help you.

200
Activity 5: Read the Labels
Household Product Active Ingredients Potential Risk(s) Hazard(s) And
Precaution(s)
Toilet cleaner Lactic Acid Eye and skin irritant Avoid contact
with eyes; maybe
harmful if
swallowed
Examine household products available at your home. From the product label, fill
in the information needed for the following table. An example is given.

201
Reflection:
1. I learned that _______________________________________________________
___________________________________________________________________
____________________________________________________________
2. I enjoyed most on ___________________________________________________
___________________________________________________________________
___________________________________________________________________.
3. I want to learn more on _______________________________________________
___________________________________________________________________
___________________________________________________________________.

202
References
Science in Today’s World-Physical Science by JerveePunzalan, Richard Monserrat,
and Rosario Laurel-Sotto pages 92-110
https://www.webmd.com/a-to-z-guides/features/decoding-product-labels#

203
Answer Key
Activity 1
Question 1. Go and find a commercial product that are available in your home and
read the labels to identify the properties of chemical ingredients. Identify the different
component of different commercial products such as detergent, soap, muriatic acid
and disinfectant and give the function of each product.
Detergents
Detergents are synthetic, water soluble cleansing agents with wetting and
emulsifying properties. They contain sodium salts of strong acids derived from
petroleum or coal. Their cleansing action is better than soap. Water alone, as a polar
compound, cannot clean effectively since it will not attach to grease and dirt, which
are nonpolar substances.
Component
Surfactant- surface-active agents, have two ends-a polar head and a non polar
tails. Polar head is attracted to water molecules, the interaction of water
molecules with one another is reduced. Nonpolar tails are attracted to greased
and dirt
- reduce the surface tension of water enhancing its ability to wet
objects, spread over more surfaces, and seep into dirt and grease.
- ability to form micelles, which consequently trap dirt or hold
grease.
Basic or alkaline- most common since they are more effective in removing
scratches, oil and fats. But they may contain hazardous ingredients
Soap
Soap is a salt composed of sodium or potassium ions paired with long
hydrocarbon chain fatty acids, which prepared from vegetable oils or animal fats. The
cleansing action of soap is weaker than that of detergent because potassium or
sodium soaps are submerged in water that has an abundance of calcium or

204
magnesium ions, a curd or an insoluble solid forms and the solution turns cloudy or
turbid
Component
• fatty acids have a polar carboxylate moiety as the head, and a
nonpolar hydrocarbon tail.
• synthetic, with sulphate or sulfonate group as the polar head
Muriatic Acid
The presence of stains and the inability to completely remove them through
extraordinary cleansing agents are caused b the hard water(contains high amount of
dissolved ions such as Ca, Mg and Fe, which form an insoluble solid with soaps.) and
lime buildup. This is common in areas where water has high mineral content. Calcium,
magnesium, and some elements in water can generate multi layered deposits on toilet
and sink. Flushing will thus be more sluggish and less effective. Dirt trapped between
layers of hard water mineral deposits stain the sink and toilet bowl, especially under
the rim and along sides above the water evaporates, an ultrathin layers of minerals is
left. More dust can then attach to the film., giving white, yellow, orange or brown colour
build up.
The properties of HCl or muriatic acid are ideal for cleansing since it is a strong
acid that can remove rust from metals. Since majority of ions that stick to the sink or
bowl include calcium and magnesium, when muriatic acid is in contact with lime and
hard water deposits, HCl rapidly dissolves them, a process accompanied by bubble
formation as represented by the equations below.
CaCO3(s) + HCl CO2(g) + H2O + CaCl2aq)
MgCO3(s) + HCl CO2(g) H2O(l + MagCl2 (aq)
After the mineral deposits are dissolved, the toilet or sink would look clean and
shiny.

205
Disinfectant
Disinfectant can rapidly inactivate or destroy various types of microorganisms
on surfaces of nonliving objects. It differs from an antiseptic, which kill microorganisms
on the skin of living things.
Types of Disinfectant
•Alcohols - it will denature the external membrane proteins of
microorganisms. A broader spectrum of bacteria on wet surface can be
killed by using a higher concentration of alcohol in water(70% ethanol or
isopropanol in water).
• Aldehydes - Formaldehyde, the ingredient in formalin, is an aldehyde
that has microbicidal and fungicidal properties.
•Acids - acetic acid and citric acid, disinfect by protonating (adding proton)
the DNA of microorganisms, which consequently disrupts its three-
dimensional structure and deactivate its function. Acid also disinfect by
acidifying(lowering pH) the environment in which microorganisms can
thrive, disrupting their protein structure.
•Bleach -Basic substances disinfect through the saponification of lipids in
the cell membrane of microorganisms. Sodium hydroxide(NaOH), also
known as lye or caustic soda, are used to disinfect buildings, but are
extremely caustic and corrosive to several metals
•Sodium hypochlorite (NaClO) - commonly know as household bleach. It
is active against vegetative bacteria, viruses, and fungi. However, NaClO
is an irritant to the eyes, skin, and mucus membrane
•Chlorine - is a oixic gas that may form when a hypochlorite reacts with
an acid or ammonia; thus, to keep this toxic gas from forming, never add
acids or ammonia to a bleach solution or hypochlorite-containing
solutions.

206
Question 2: What are the active and inert component of common cleaning
product?
The active ingredients is the component of a product which, regardless of
quantity, directly enables it to serves its purpose. In contrast, the inert ingredients refer
to all the other substances in a product. An inert ingredient does not affect the action
of the active ingredient.
Activity No. 2
Chemistry Behind Common Cleaning Materials
Fill in the box!!
Common Active and Inert Components of Cleaning Products
Commercial
Product
Active Ingredient(s) Inactive Ingredients
Detergent Anionic surfactant
such as sodium lauryl
sulphate(SLS)
Builders to soften water: sodium carbonate,
sodium silicate, borax(Sodium tetraborate)
Bleaching agents: sodium percarbonate, or
sodium perborate
Fillers to add bulk: sodium sulphate(if powdered),
water and alcohol(if liquid)
Citric acid or other scents for fragrance
Soap Saponification
products such as
sodium palmitate,
sodium stearate,
Scent, fragrance oils, dye or collar additives,
preservatives (BHT) parabens, benzoate, and
propylene glycol)
The active ingredients is the component of a product which, regardless of quantity,
directly enables it to serves its purpose.
The inert ingredients refers to all the other substances in a product. An inert ingredients
does not affect the action of the active ingredient.

207
potassium stearate,
sodium tallowate and
sodium cocoate
If antibacterial soap:
triclosan or
triclocarbon
Hardening agents for bar sopas: olive oil and
canola oil
Emolient to soften skin: glycerine
Emulsifiers or thickeners: polyethylene glycols
like PEG-6-methyl ether (makes the scents and
dyes blend evely with the soap.)
Water softeners: tetrasodium EDTA ,
pentasodiumpentetatetetrasodiumetidronate
Sorbitol (makes the soap more transparent)
Titanium dioxide (makes the soap opaque or
whither)
Muriatic Acid Hydrochloric acid
(HCl)
Water as a solvent
Disinfectants Halogen-based
compound
Usually water for dilution, or an organic solvent if
the active ingredient is poor.

208
Activity no.3
Stop, Look and Protect
Safety Measures for Some Commercial Products
Product Possible Risks Safety Measures
Detergent Eye irritant with direct
contact; may lead to skin
irritation with prolonged
contact
Can cause vomiting,
nausea, 0r diarrhea if large
amount is swallowed
Avoid exposure
After using the product, wash
both hands before eating or
drinking
Wear hand gloves with people
sensitive to skin.
Soap Eye irritant with direct
contact; may lead to skin
irritation with prolonged
contact
Can cause vomiting,
nausea, 0r diarrhea if large
amount is swallowed
Avoid contact with the eyes and
skin. Wear safety glasses if
needed.
Do not ingest
Various chemicals have detrimental effects on human health. Some people may be
allergic to certain active and inactive (or inert) ingredients. It is therefore important
to check the ingredients of the products before making purchases.

209
Muriatic acid Can form flammable H2
gas if it comes in contact
with certain metals
Reacts with oxidizing
materials, caustic
materials, and some
metals
Corrosive: can burn eyes
and skin on contact
Keep container closed and away
from incompatible substances.
Ensure that the container is not
damaged.
Store in a dry and cool place. Do
not mix with metals or alkaline
substances.
Use old clothes with long sleeves
to prevent the exposure of skin to
HCl fumes. Wear rubber gloves
before use.
Use toilet brush to spread
muriatic acid on the rims. Flush
multiple times to help completely
wash off HCl before using the
toilet to prevent skin burns.
In case of spills, neutralize with
liquid soda ash, slaked lime, or
sodium bicarbonate.
Wear tight fitting, vapour proof
goggles to prevent the burning of
the mucosa of eyes.
Do not inhale the vapors
Disinfectants Depends on the type of
disinfectant, but generally;
Avoid prolonged contact with skin
and avoid contact with eyes

210
• Can irritate eyes,
stomach, lungs, and
nose
• Cause light-
headedness if one
is exposed to
alcohol vapors
Flammable and may
explode
May aggravate some skin
conditions
Avoid inhaling directly from
containers.
Avoid exposure to flames and
extreme heat. Keep product
container firmly closed if not used
and when it is being transported.
Always wear gloves. Wash
thoroughly after use.
Activity No. 4
Surveying the house
Cleaning Materials/
Personal Care Product
General Classification
(Soap, detergent,
disinfectant, Muriatic
acid)
Specific Classification
(Applicable for disinfectants: alcohol,
aldehyde, oxidizing agent, acid, base,
halogen-based compound)
Betadine Disinfectant Halogen-based compound
Isopropyl Alcohol Disinfectant Alcohol
Safeguard Soap Fatty Acid
Tide Detergent Surfactant
Zonrox Bleach/disinfectant Hypochlorite-containing solution
Agua Oxigenada Disinfectant Oxidizing agent
sanitizer Disinfectant Alcohol
Lye Disinfectant Basic substance
Conduct a survey of common examples of cleaning materials or personal care
products available at your home. List as many as possible and classify them
accordingly by completing the table below. The first one is given to help you.

211
formalin Disinfectant Aldehyde
Muriatic acid Muriatic acid Hydrochloric acid
Ariel powder Detergent Surfactant
Anti-bacterial downy Disinfectant Oxidizing agent
Activity No. 5
Read the labels!
Examine household products available at your home. From the product label, fill in the
information needed for the following table. An example is given.
Household Product Active Ingredients Potential Risk(s) Hazard(s) And
Precaution(s)
Toilet cleaner Lactic Acid Eye and skin irritant Avoid contact with
eyes; maybe harmful
if swallowed
Betadine Iodine Low toxicity Avoid inhaling
Isopropyl alcohol isopropyl irritate damaged
skin
Avoid with high
flammable,
Agua oxinada Hydrogen peroxide Irritant Damages clothing if
used undiluted
Muriatic acid Hydrochloric acid Damaged skin, can
form flammable H2
gas
Avoid contact with
eyes; harmful if
swallowed. Store in a
dry and cool place.
Do not mix with metal
Ariel powder Surfactant Slight to moderate
irritant to the eye,
skin and digestive
tract
Avoid exposure to
detergent, wear hand
gloves

212
Safeguard Fatty acid Eye irritant, when
swallowed can
cause vomiting and
nausea
Do not ingest
sanitizer alcohol Can irritate eyes,
stomach, lungs and
nose
Avoid contact with
eyes. Avoid
exposure to flames
and extreme heat
Prepared by:
CONSOLACION B. BALUGA
Piat National High School

213
PHYSICAL SCIENCE
Name: ____________________________ Grade Level: _________
Date: _____________________________ Score:______________
Practical Application Of Chemistry
https://www.hunker.com/12483474/types-of-cleaning-agents
A cleaning agent can be described as any product used to clean. This does not
mean a tool for cleaning. A broom, a mop or a paper towel would not be classified as
a cleaning agent. So, a cleaning agent is not the instrument used for cleaning but
rather the solvent or product that actually does the cleaning. They are either natural
or synthetic substances that are used to aid the cleansing process.
Some of the most typical kinds of cleaning agents are broadly defined
as disinfectants, deodorizers, detergents, polishes, abrasives and other types of
cleaning agents. These are all chemically different and perform different tasks, but
they are all used in the pursuit of a cleaner environment. They remove dust, bacteria,
grease, mold, fingerprints, dirt, cooking fluids and organic matter.
Almost every single cleaning agent can be classified as one of the following
four varieties: alkaline, acidic, neutral or degreaser. These four categories are the
broad umbrella terms for cleansers that have similar chemical properties and react in
similar ways with the substances that need to be cleaned. Certain cleaning jobs are a
job for alkaline cleaners only, while other messes or bacteria or stains may require the
use of a detergent or a degreaser or both.
All cleaning agents are not created equal. To understand exactly what cleaning
agent to use for a specific cleaning job, it is important to understand that all cleaning
agents are classified by their pH levels. pH stands for "potential hydrogen." This

214
means that an agent is rated on the pH scale for how many hydrogen molecules it is
likely to add when added to water. The scale goes from acid to neutral in the middle
with alkaline on the far end.
All cleaning agents are given a rating on the pH scale that goes from zero (most
acidic) to 14 (most alkaline). In the center, at seven on the scale, is water. Cleaners
like detergent are more alkaline and fall somewhere around 10 or 11 on the pH scale,
while acids like white vinegar or lemon fall closer to two.
Many people assume that the higher a cleaning agent's pH, the stronger a
cleaner it is. This is actually incorrect. pH is not a measurement of cleaning
strength or power. Something with a very high pH can be the absolute wrong variety
of cleaning agent for a particular mess. The trick to finding the right cleanser for
your situation is to be aware of the alkaline or acidity level that you need and choose
your cleaning agent accordingly based on its pH.
Acidic cleansers are any cleaning agent that can be described as low on the
acid side of the pH spectrum. These cleansers generally contain minerals like chelates
or sometimes hydrochloric acid. The goal of acidic cleaning agents is generally
to brighten up metals or dissolve existing minerals. For example, a grime-covered
stove will benefit from a spray containing vinegar or another acid because the acid
helps to dissolve and break up the bonds of the grease on the stove.
Acidic cleansers are also used in bathrooms to break up lime, scale and calcium
deposits that have adhered to the bathtub, sink and other areas. These deposits are
heavily prevalent when water is regularly used in a room. This is why bathroom fixtures
and hardware can take on a dull, spotty appearance after a while. Acidic cleansers
help to break up the film so they shine again.
Alkaline cleaners are all the way at the other end of the cleaning agent
spectrum. The role of an alkaline cleansing agent is to dissolve fats, oils and
proteins. This is found in dirt and oil but also in organic matter like blood and body

215
fluids like sweat. Alkaline cleaners break down these entities and in doing so make
them easier to remove with water.
Alkaline cleaners are in almost every case meant to be used with water. Water
is the partner with an alkaline cleaner like bleach or OxiClean. While the cleansing
chemicals in an alkaline cleanser may break down the matter that needs to be
cleaned, water is the critical component. After using the alkaline cleaner, the water
washes away what the cleaner itself has helped to dissolve.
Degreasers serve a similar function as alkaline cleaners in that they can help
break down oil, fats and petroleum byproducts. They are useful in a variety of settings
but particularly of use in a construction capacity or when cleaning kitchen
appliances or hard kitchen surfaces and floors. Degreasers are also a critical part
of most facility maintenance cleaning regimens.
Neutral cleaners are the cleansers that are not brought out to break down
matter but are mostly used in order to clean dust or remove surface dirt. Water is
one of the most popular neutral cleaners. While it lacks cleaning chemicals, it has the
right pH for removing surface dust and debris from floors, tables and counters.
While housekeepers and scientists all generally agree that water is the most important
and effective of all cleaning agents, certain materials require specific types of cleaning.
Whether it's a mirror, a window or a tabletop, glass cleaning has its own set of
requirements and rules. For glass, you want a cleaner that is powerful enough to
dissolve things like fingerprints, grease, dust and other grime without leaving
streaks or marks.
Ideally, you will want to choose a cleanser without ammonia. Ammonia is a
harsh chemical that can irritate the respiratory system and is toxic in large quantities.
While many mainstay glass-cleaning products do contain ammonia, the emphasis on
natural products in recent years has given the market a significant number of
nonammonia cleansers that rely on household ingredients like vinegar and baking
soda to get the job done.

216
The most-recommended glass cleaner is Sprayway glass cleaner. It is an
aerosol spray that is good for mirrors, windows, tile and enamel surfaces. The foam
does not drip unlike many ammonia-based liquid cleaners, and it is strong without
being overpowering. The most highly recommended natural cleaner is Method brand's
glass and surface cleaner. It is ammonia free and entirely nontoxic, which is a benefit
for families with small children or pets.
Cleaning products, while safe and effective, must be handled appropriately to
protect the health of consumers and their families. Users should follow all safe
handling instructions on a product’s label before using a particular cleaning product.
The Federal Hazardous Substances Act (FHSA) requires precautionary
labeling on containers of any consumer product that poses a likelihood of injury, to
help consumers safely store and use those products and to provide information about
immediate first aid steps to take if an accident happens.
Each of the cleaning agents has a specific purpose and should only be used as
intended, otherwise dangerous and costly mishaps can occur.
These are the following aspects of using cleaning agents:
• Safety aspects of handling cleaning agents
• Labelling of chemical cleaning agents
• Chemicals used in different types of cleaning agents
• Appropriate use of the different types of cleaning agents
• Tips for using chemical cleaning agents
Activity 1: Answer the Following questions
What are the classifications of cleaning agents?
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
____________________________________________________

217
https://www.chemicalsafetyfacts.org/cleaning-products/
How are cleaning agents classified?
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
______
https://www.ajar.id/en/post/types-of-cleaning-agents-and-chemicals
What are acidic cleansers?
___________________________________________________________________
___________________________________________________________________
________________.
What are alkaline cleansers?
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
_________
https://poloandtweed.com/blog/types-cleaning-agents-used-housekeepin

218
Activity 2: Hazard Pictograms
Directions: Identify the given symbol found in labelling products.
_________________
________________
________________
________________
___________

219
___________
___________
_________
Activity 3: Cleaning Agent Detector
Directions: Complete the Table
Apart from the daily routine of dusting and cleaning, housekeepers are often
faced with a cleaning job which requires special treatment. A cleaning agent can be
described as any product used to clean. Give the cleaning job of the following
cleaning agent. https://poloandtweed.com/blog/types-cleaning-agents-used-housekeeping
Cleaning Agent Cleaning Job
Diluted liquid household bleach (sodium
hypochlorite)
Sodium hydroxide
Sodium hypochlorite and sodium
hydroxide
Solvents and alkaline cleaning agents
Acetic acid (vinegar)
Citric, oxalic, sulfamic or hydroxyacetic
acid to dissolve the minerals

220
SELF-TEST
Multiple choice: Choose the letter of the correct answer.
1. A natural or synthetic substances that are used to aid the cleansing process.
a. cleaning agent c. cigarettes
b. alcoholic beverages d. cosmetics
2. The best way to handle a household cleaner is to:
a. read the label c. keep a window open
b. use rubber gloves d. none of the above
3. Hazardous cleaners are those that:
a. irritate the skin c. cause dizziness if used in an unventilated area
b. are harmful if swallowed d. all of these
4. Which label wording is the safest when looking to buy a household product?
a. caution c. danger
b. warning d. all of these
5. If you only need a hazardous chemical like a lawn pesticide every now and
then, how much of it should you buy?
a. The size that's the best buy for the money
b. Only as much as you think you will need
c. Twice as much as you need, so you'll have extra for later
d. None of the above
6. Which of these is the best way to store hazardous chemicals in the home?
a. In the original container in a safe place
b. In a replacement container with an airtight lid or cap
c. In a used, but clean jar
d. None of the above
7. What's an indication that you should stop using a chemical?
a. You feel dizzy c. You develop a headache
b. You feel nauseated d. Any of the above
8. What's the best way to dispose of hazardous chemicals used at home?
a. Put them in a leak-proof container in the trash
b. Carefully pour them down the drain
c. Read the labels to see how to dispose of each
d. Bury them in the yard

221
Circle True or False
9. Manufactures of household cleaners are required to list all ingredients of their
products
10. Labels of all home and garden products must be precise, showing exactly
what substances are present and the amount of each
11. Household products must be tested for their long-term health effects before
being placed on the market.
12. Products placed on the market are not guaranteed to be safe
13. If ingredients are listed as “inert,” they are harmless
14. “Active” ingredients make up the major portion of a product
15. A hazardous substance is described as highly toxic, flammable or
combustible, corrosive, an irritant, a strong sensitizer, radioactive, capable of
generating pressure, or capable of causing substantial illness or injury.
Reflection:
1. I learned that _______________________________________________________
___________________________________________________________________
____________________________________________________________
2. I enjoyed most on ___________________________________________________
___________________________________________________________________
___________________________________________________________________.
3. I want to learn more on _______________________________________________
___________________________________________________________________
___________________________________________________________________.

222
References
https://www.chemicalsafetyfacts.org/cleaning-products/
https://www.foodsafety.ca/blog/4-types-cleaning-agents-and-when-use-them
https://www.cleaninginstitute.org/understanding-products/about-cleaning-
product-ingredients

223
Answer Key
What are the classification cleaning agents?
Possible Answer
Cleaning agent can be classified as one of the following four varieties: alkaline,
acidic, neutral or degreaser. These four categories are the broad umbrella terms for
cleansers that have similar chemical properties and react in similar ways with the
substances that need to be cleaned.
How are cleaning agents classified?
Possible Answer
All cleaning agents are not created equal. To understand exactly what cleaning
agent to use for a specific cleaning job, it is important to understand that all cleaning
agents are classified by their pH levels. pH stands for "potential hydrogen." This means
that an agent is rated on the pH scale for how many hydrogen molecules it is likely to
add when added to water. The scale goes from acid to neutral in the middle with
alkaline on the far end. All cleaning agents are given a rating on the pH scale that goes
from zero (most acidic) to 14 (most alkaline). In the center, at seven on the scale, is
water. Cleaners like detergent are more alkaline and fall somewhere around 10 or 11
on the pH scale, while acids like white vinegar or lemon fall closer to two.Many people
assume that the higher a cleaning agent's pH, the stronger a cleaner it is. This is
actually incorrect. pH is not a measurement of cleaning strength or power.
What are acidic cleansers?
Possible Answer
Acidic cleansers are any cleaning agent that can be described as low on the
acid side of the pH spectrum. These cleansers generally contain minerals like
chelates or sometimes hydrochloric acid. The goal of acidic cleaning agents is
generally to brighten up metals or dissolve existing minerals.
What Are Alkaline Cleansers?
Possible Answer
Alkaline cleaners are all the way at the other end of the cleaning agent
spectrum. The role of an alkaline cleansing agent is to dissolve fats, oils and
proteins. This is found in dirt and oil but also in organic matter like blood and body

224
fluids like sweat. Alkaline cleaners break down these entities and in doing so make
them easier to remove with water.
Activity No. 2
Health hazard/Hazardous
to the ozone layer
Serious health hazard
Highly Extreme
Flammable
Hazardous to the
Environment
Gas under pressure
Acute toxicity
Oxidizing
Corrosive

225
Cleaning Agent Detector
Apart from daily dusting and cleaning, housekeepers often face difficulty in
cleaning jobs which requires special treatment. A cleaning agent may be described
as any product used to clean something up.
Give the cleaning job of the following cleaning agent.
Cleaning Agent Cleaning Job
sodium hypochlorite (Diluted liquid
household bleach)
Fabric stained with fungi, mould and
mildew
Sodium hydroxide Kitchen drain clogged with fat and grease
Sodium hypochlorite and sodium
hydroxide
Bathroom drain clogged with hair and soap
Solvents and alkaline cleaning agents Glass stained with body oils
Acetic acid (vinegar) Glass stained with mineral salts
Citric, oxalic, sulfamic or hydroxyacetic
acid to dissolve the minerals
Showerhead clogged with mineral deposits
from hard water (limescale and rust)
Self -Test
Answer key
1.A 11. F
2. A 12. T
3. D 13. F
4. D 14. F
5. B 15. T
6. A
7. D
8. C
9. F
10. F
Prepared by:
CONSOLACION B. BALUGA
Piat National High School

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