1. NAME: Pratheek Bhavadas Menon
STD: XI Science
DIV: C (C.S)
ROLL NO: 33
TOPIC: Role of Chemistry in Domestic Activities
GUIDED BY:
2. “ I am extremely pleased to state that Mast. Pratheek
Menon has taken keen interest and fascination in the
topic entitled:
‘Role of Chemistry in Domestic Activities’
This topic is done under my guidance and supervision
during the academic year 2015-16 by Std XI C (C.S).
3. I hereby declare that this project is the
result of my own research work and the
same has not been done previously.
PLACE: Dombivli (East)
Date: 16th November
2015
4. Gratitude is a pearl of great price in the treasury of values.
Its beauty grows when it is expressed.
The researchers’ (students’) wishes to express has deep
sense of gratitude to his guide
who was the guiding spirit throughout the entire work.
The student also expressed my sincere gratitude to the
principal ‘Shri. D.H. Tiwari sir’ for his valuable support.
I also express my gratitude to all teaching and non-teaching
staff for their assistance until the end of the work.
Student Name:
5. Chemistry is a branch of physical
science that studies the composition,
structure, properties and change of
matter. Chemistry deals with such
topics as the properties of individual
atoms, how atoms form chemical
bonds to create chemical
compounds, the interactions of
substances through intermolecular
forces that give matter its general
properties, and the interactions
between substances through
chemical reactions to form different
substances.
Chemistry is sometimes called the central science because it bridges other natural
sciences, including physics, geology and biology and also because of its role in
connecting the physical sciences, which include chemistry, with the life sciences and
applied sciences such as medicine and engineering. The nature of this relationship is
one of the main topics in the philosophy of chemistry and in the study of measuring
and analysing science, technology and innovation.
6. Everything is made of chemicals. Many of the changes we
observe in the world around we see that caused by chemical
reactions. Chemistry is very important because it helps us to
know the composition, structure& changes of matter. All the
matters are made up of chemistry. In our every day like various
chemical are being used in various from, some of those are
being used as food, some of those used clanging etc. We are
living our own life and chemistry is in every part and moment
of our life . We must realize the importance of chemistry in our
daily life . From waking up in the morning to the time of
sleeping , chemistry moves with us like our shadow and even
while we sleep , chemistry is there with us . If you know a little
about the facts of chemistry , then you may realize the real
time importance of chemistry in our every moment of life .
When we walk , when we take food , when we inhale & exhale
( breathe ) , when we bath , when we drink , when we do any
work that we do in our everyday life , everywhere and
everytime , chemistry is always with us
7. The word ‘domestic’ means of or
relating to the home, the household,
household affairs, or the family. So,
basically, domestic activities are the
activities which are in some way or the
other related to our home or our
households, i.e. these are the activities
which are significant for, or make an
impact on our daily lives. In simple
words, all activities performed at home
on a daily basis can be termed as
domestic activities. Common examples of
domestic activities include cooking food,
washing clothes and dishes, cleaning,
bathing, make-up etc.
8. Cooking involves a lot of chemistry and is essentially
a series of chemical reactions. Knowing about this
kitchen chemistry can help one to understand much
more about what’s happening – and why their
recipes sometimes go wrong. Chemistry explains
how food changes as we cook it, how it rots, how to
preserve food, how our body uses the food eats,
and how ingredients interact to make food. Foods
we eat have to do with chemistry. They consist of
organic compounds like carbohydrates--starch and
sugar, protein, and lipids. Other nutrients like
vitamins and minerals and water are all important
chemical compounds. Fermentation, another
chemical reaction produces beer and wine, cheese
and bread.
Complex chemical reactions go on in food all of the
time – even if you’re not cooking them. Some of
these reactions make food go off.
For example, bananas turn brown because a
hormone within them triggers the release of
ethylene gas (C2H4). This accelerates the ripening
processes until the banana becomes over-ripe.
9. Why are Curries ‘Hot’?
Why do we sweat through that green curry? What makes it taste so hot ? The short answer is
capsaicin i.e. (CH3)2CHCH=CH(CH2)4CONHCH2C6H3–4–(OH)–3–(OCH3). The
capsaicin allows calcium ions to flood cells. This trips a pain signal and before you know it you
are reaching for a glass of water.
What Happens to Meat When You Cook it?
Meat is animal muscle, 75% of which is water. The rest is protein (about 20%) and fat (5%), as
well as small amounts of carbohydrates, acids and minerals. The protein molecules are in bonded
coils, but as heat is applied the bonds break and the coils start to unwind. If it’s red meat (lamb,
beef) it begins to turn brown as the myoglobin reacts to the heat. Heat triggers iron atom
oxidation. The iron atoms in the protein lose an electron and this gradually changes the colour
from red to brown.
Why Does Popcorn Pop?
Popcorn kernels are around 13.5% water, and when you heat the popcorn the water in the kernel
boils and turns to steam. The hull is sealed so the steam creates pressure inside. When the
temperature rises to 180°C and the pressure is at nearly 1000 kPa (kilopascals), the shell explodes
– or pops. If the kernel contains more than 13.5% water it will pop into a thick dome shape
instead and won’t be as fluffy and crisp. On the other hand, if it doesn’t have enough water it
won’t build up enough steam
10. What makes a cleaner work? How much
chemistry is involved in removing grease
from a stove top or grit from a concrete
floor? The answer to these and other
questions lies within words like surfactant,
solvent, chelating agent and builder.
Understanding the basic elements of a
cleaner’s effectiveness against different
types of soil is essential to the “Chemistry
of Cleaning.” Part of the importance of
chemistry is it explains how cleaning works.
We use chemistry to help decide what
cleaner is best for dishes, laundry,
ourselves, and your home. We use chemistry
when use bleaches and disinfectants and
even ordinary soap and water. How do they
work? That's chemistry!
11. Surfactants
A surfactant is the most important part of any
cleaning agent. The word surfactant is short for
“Surface Active Agent.” In general, they are
chemicals that, when dissolved in water or another
solvent, orient themselves at the boundary between
the liquid and the dirt, and modify the properties of
the interface. How does a surfactant work? All have a
common molecular similarity. One end of the
molecule has a long nonpolar chain that is attracted
to oil, grease, and dirt (the hydrophobe). Another part
of the molecule is attracted to water (the hydrophile).
The surfactant lines up at the interface as
diagrammed below. The hydrophobic end of the
molecule gets away from the water and the
hydrophilic end stays next to the water. When dirt or
grease is present (hydrophobic in nature) the
surfactants surround it until it is dislodged from the
boundary. Notice in diagram 4 that the dirt molecules
are actually suspended in solution.
12. Chelating Agents
One of the major concerns we have in dealing with cleaning
compounds is water hardness. Water is made “hard” by the
presence of calcium, magnesium, iron and manganese metal
ions. These metal ions interfere with the cleaning ability of
detergents. A chelating agent combines itself with these
disruptive metal ions in the water. The metal ions are
surrounded by the claw-like chelating agent which alters the
electronic charge of the metal ions from positive to negative
(see diagram below.) This makes it impossible for the metal
ions to be precipitated with the surfactants.
A preservative is nothing more than a substance that protects
soaps and detergents against the natural effects of aging such as decay, discoloration, oxidation and
bacterial degradation. Synthetic detergents are preserved differently from soaps as we will see. In
soaps, preservatives are used to forestall the natural tendency to develop rancidity and oxidize
upon aging. Butylated hydroxdytoluene (BHT) and stannic chloride are commonly used in this
application
Preservatives
13. Have you ever wondered how a cup of detergent
cleans soiled jeans, towels, socks, and other
articles in your wash, or how cleaning fluid at the
dry cleaner whisks away that grease stain from
your suit? And why are hair spray, vinegar, club
soda, and baking soda surprisingly effective dirt
and stain removers in an emergency? The answers
lie both in the chemical properties of various
types of dirt and stains and in the ways that the
cleaning agents chemically interact with them.
Dirt and stains typically consist of particles, such
as minerals from soil, protein and other organic
matter from living things, or bits of black carbon.
The particles are trapped on cloth fibers by grease
and oil, which cannot be dissolved in water.
Anything that can loosen the grease and oil from
the fibers and disperse (scatter) these substances
in the wash water or dry-cleaning solution will
remove the dirt and stains.
14. How Soaps and Detergents Work
Soaps, detergents, cleaning fluids, and many emergency stain removers are effective
cleaners because they can dissolve and emulsify (break up and suspend) the oil and
grease that holds dirt in place. The grease and trapped soil particles then can be
carried away in the water or dry-cleaning solution. But these agents differ widely
in their dirt-fighting activities and the conditions under which they work. Soaps
are excellent for cleaning our hands, face, and body, because the loosened dirt is
rinsed away immediately. But soaps have definite drawbacks for cleaning laundry.
For example, soaps often allow dirt lifted from clothes to redeposit on the clothes
before the wash cycle is finished.
How Enzymes Help In Cleaning
Compounds called enzymes enhance the cleaning action of surfactants. Enzymes
are complex molecules made by living organisms. Various food stains include blood,
meat gravy, milk, eggs, and grass extracts. Enzymes break down these substances
into simpler forms that can be removed by other components in the detergent. The
tenderizer contains enzymes intended to partially digest proteins in meat before it is
cooked. But when poured onto clothing or carpets, the enzymes can also break up
protein molecules in stains.
15. BLEACHES
Bleaches do not remove dirt particles but make them colorless or nearly colorless. Liquid chlorine bleach is the
most powerful of the chemical bleaches used as laundry aids. Chlorine bleach not only whitens clothes, but also
disinfects and deodorizes them. It can, however, remove color from clothes.
A less powerful chemical bleach is oxygen bleach. Because it is safe to use on most fabrics, oxygen bleach is the
one most frequently added to detergents. It is also used in presoak products to aid in cleaning heavily soiled
clothes or in helping to remove stubborn stains before clothes are put through a normal washing machine cycle.
DRYCLEANING
The most effective way of removing dirt and stains from water-sensitive articles is dry cleaning. Dry cleaning is a
process in which a liquid other than water is used to dissolve and flush away oil and grease along with
underlying soils. The most useful solvents in dry cleaning are water-insoluble liquids derived from petroleum,
particularly a carbon- and chlorine-containing compound called perchloroethylene. Dry-cleaning solvents,
unlike water-based detergents, do not repel oil and grease molecules. Instead, the solvents surround and dissolve
these molecules. Many commercial dry cleaners also add special detergents to their solvents to further loosen soil
particles.
