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1. What I
know?
What I want
to know?
What I
learned?

2. Learning Competencies:
1. Describe gases.
2. Explain the postulates of the
kinetic theory as applied to
gases.
3. Relate how these postulates
account for the properties of
gases.

3. 11 elements of gases under normal
atmospheric condition
1.Chlorine
2.Hydrogen
3.Oxygen
4.Nitrogen
5.Flourine
6. Helium
7.Argon
8. Neon
9.Krypton
10.Xenon
11.Radon
Ozone- another form of
oxygen (gas at room
temperature)

4. Name of Gas/
Mixture of Gases
Some Useful Facts Uses
Air Air is the gas all
around us.
Its a mixture of
several different
gases, mainly
nitrogen (78%),
oxygen (21%), and
other gases (1%)
It supports balloons
and airplanes
Without air, we
cannot breathe and
fires won’t burn.
Natural Gas Natural gas comes
from the ground.
It burns easily
(flammable)
Natural gas is used
as a fuel for heating.
Oxygen Oxygen is produced
by plants (during
photosynthesis).
Without oxygen, we
cannot breathe and
fires won’t burn.
Oxygen is used in
hospitals to help us
breathe.
Oxygen is used in
manufacturing
metals as well as
steel in welding.

5. Name of Gas/ Mixture
of Gases
Some Useful Facts Uses
It is combined with
hydrogen for the
propulsion of space
shuttles.
Carbon Dioxide Carbon Dioxide is
needed by plants when
they make food (during
photosynthesis).
All living organisms
breathe out carbon
dioxide when they
make energy (from
food)
Carbon dioxide is the
gas in fizzy drinks It is
also used in fire
extinguishers.
Nitrogen Nitrogen is the main
gas in the air (about
78%)
Nitrogen is use to
make plant food
(fertilizer) and is also
used in explosives.

6. Name of Gas/ Mixture
of Gases
Some Useful Facts Uses
Water Vapor Is formed when water
evaporates. There is a
lot of water vapor in the
air we breathe.
When water vapor in
the air cools down it
forms water vapor.
Helium There is a small amount
of helium in the air. Its
very light gas and is
used in the balloons to
help them float.
It helps balloons to
float.
Argon There is a small amount
of argon in the air.
Argon is the gas inside
electric light bulbs.

7. Common Properties of Gases
 1. they have indefinite shape.
 2. two or more gases can be readily mixed
evenly and completely because gases diffuse
rapidly.
 3. Compressible and expandable depending
on the pressure applied to it.
 4. less dense. Their density varies at the
temperature and pressure changes.
Density of air is 0.0012 g/cm3

8. Volume
 is the quantity of three-dimensional space occupied
by a gas.
 Denoted by the symbol V
 S.I Unit is in Liters (L).
 Can also be expressed in mL, cm3 ,m3 ,dm3
1 litre= 1000 millilitres
1 millilitres= 1 cubic centimetre
1 cubic centimetre= 1000 cubic centimetre
1L=10dm3 =10 m3 =1000mL=1000cm3

9. Pressure
 Is the force exerted by the gas per unit area.
 depends on the kinetic energy of the molecules.
 Pressure and temperature is directly proportional.
Pressure (P)= force or Pressure (P)= (mass) (acceleration)
area area
 The S.I. Unit for pressure is (Pa)

10. 1 Pa = 1 N
1 m²
1 Pa= 1 kg.m/s²
1 m²
1 Pa= 1kg.m/s²

11. Other units of pressure
 atmosphere (atm)
 millilitre of mercury (mmHg)
 Torr
 Bar
 Kilopascal (kPa)
 Pounds per square inch (psi)
1 atm=760 mm of Hg=760 torr=1.01325 barr=101.325 kPa=101. 325 x 103N m²

12. Intruments use to measure Pressure
 Barometer
 Manometer
 closed tube manometer
Open tube manometer

13. Temperature
 Is the measure of average kinetic energy of
the particles of gas.
 Gas expands when temperature is increased.
 Gas contracts when temperature is
decreased.
 °F , °C, K
 Used by the help of thermometer.
 Absolute zero= -273. 15 °C

14. To convert Celsius to Kelvin:
K= °C + 273.15
Celsius
Scale
Kelvin
Scale
Absolute
zero
-273.15 0
Freezing
point of
water
0° 273.15
Boiling
point of
water
100° 373.15

15. Amount or Number of Moles
 The mass of the gas is related to the number of moles
of the gas.
 Kg or g
Number of moles (n) = mass of the gas
molar mass of the gas
n= m
M

16. Kinetic Molecular Theory of Gases
 Gas , like any other states of matter, consist of very
tiny particles, each of which has mass. Gases are
most likely empty space because of a wide distance
between these tiny particles. Thus, making gases
compressible and have low density. The density of
gases varies with changes in temperature and
pressure.
 Gas particles move rapidly in straight lines, travel
constantly, and in random directions.
 Gases diffuse very rapidly that allows two or more
gases to mix readily when combined.

17.  Because of the wide spaces between gas particles, the
forces of attraction (Van der Waals Force) between
them are negligible.
 Gas particles collide with each other or with the walls
of its container but do not lose their kinetic energy;
instead, it is only transferred to the lower-energy
particle and will continue to move. In short, energy is
conserved in elastic collisions of gas particles.
 All gases have the same average kinetic energy at a
given temperature of gas. The average kinetic energy of
gas particle is directly proportional to the absolute
temperature of the gas. This means that gas particles
might have higher kinetic energy at a higher
temperature and vice versa.

18. Summary
 Gases are fluids with very low densities, are
highly compressible, and expand/contract to
completely fill whatever closed container
they are put in.
 The Kinetic Molecular Theory of Gases
provides a model to explain behavioral
properties of gases.

19. Assignment
What are the different gas laws?
Write their formulas.
Reference: 324-337 Science book

20. Prepared by :
Ms. Ella B. Llamas