Value Based Questions in Chemistry
1. Manu went with his father to a Shopkeeper who showed them two types of batteries,
one with lead plates and
the other with cadmium
plates. The battery with cadmium plates was more expensive than the lead battery.
Manu’s father wanted to purchase lead battery as it was
cheaper.
a. As a student of
chemistry, why would you suggest to Manu’s
father to buy the
expensive cadmium
plate battery. Give two reasons. (2)
b.
What are the values
associated with the above decision?
(1)
Ans:
a. Cadmium plate battery
though expensive is not
as strong a pollutant
as lead. Lead salts
being insoluble in water if ingested into our system cannot
be
excreted out. Whereas Cd
and Ni salts are water
soluble, therefore get excreted and
hence do not get biomagnified
in the body.
b. Keeping the
environment safe
from pollution due to
lead.
2. Kalavati wanted to
give her baby a medicine for
fever. She added boiled and cooled water as per the instruction,
to the contents of
the
bottle, upto the
mark. She shook the bottle. Then gave a spoonful of the
medicine to
the baby. As
a student of chemistry
answer the following questions:
a. Why did she shake up the
contents? What is the process called? (2)
b. What is the value associated with selling
medicine in this form? (1)
Ans:
a. She shook the
contents of the bottle
to bring the contents into the form of a sol. Absorption of medicine are easier
in the colloidal form.
This process of agitating a precipitate into colloidal
sol is called as peptization.
b. When the
medicine is
sold in anhydrous form it has a higher shelf
life and thus can be stored
for a longer
time. This
is a way of being thrifty
by not wasting the available resources.
3. After entering a closed coal
mine area, Ravi found difficulty in
breathing, also felt
nausea.
a. What could be
the
reason for this? (1)
b. How
could Ravi estimate the level
of the pollutant? (1)
c. As a citizen of
the
country what should
be his course of action
further? (1)
Ans:
a. In coal mines due to
lack of oxygen a small
percentage of carbon monoxide is
formed. This carbon monoxide being
poisonous
gives
the
symptoms.
b. Ravi could estimate the level
of CO using I2O5.
c. Ravi
should inform the
concerned authority about the excess of CO in the coal
mine.
4. Sudanshu made a model of the unit cell of diamond.
It
resembled the unit cell of ZnS. If the
unit cell of ZnS has 4 units of ZnS per unit cell.
It has
the
same packing efficiency as ZnS.
But diamond is the
hardest
known substance.
a. What is
the
number of atoms of
carbon per unit
cell of diamond? (1)
b. Explain the
reason for the above concept. (1)
c. What is the value
that Sudanshu can derive from these facts? (1)
Ans:
a) The number of atoms
of Carbon per unit cell is
8 in
diamond.
b) The C—C bond is
very strong in diamond (due to small
size of Carbon)
unlike the Zn—S
bond in ZnS.
c) Though from the same background ie with
the
same structure the property can be different, thus, with a little
effort, we can do
same things differently
and bring about
major changes.
5. Kartik went to
a sugar producing factory.
He noticed an alcohol producing
unit associated with it. Generally
alcohol is prepared industrially in places where sugar is extracted from sugarcane.
a. As a
student of chemistry,
explain the reason for this.
(2)
b. What is the value
derived from this fact? (1)
Ans:
a. The molasses that are bi-products of
sugar industry can be used in making
alcohol.
b. Recycling of
industrial waste keeps the environment clean.
6. Large amount of
electricity is obtained in our country from burning of
coal.
The
carbon in coal
is lost as carbon dioxide, and water as water
vapour. The substances left
behind are minerals. These are known as fly ash. Fly ash is
a major environmental hazard. Faseeh did a project on how
to use this fly ash in
building roads and in making roofing tiles. He was
appreciated by the judges. What was the value for which he was
appreciated?
Ans: Recycling of
industrial
waste keeps the environment clean. (3)
7.
Ashraf is 50 years
old and has diabetes. He
uses saccharine as sweetening
agent in tea and
coffee and sugar free in sweets. Lakshmi too is
diabetic.
She controls her sugar level in diet by using less
sugar and by exercising.
a. Who is able to
handle diabetes more efficiently and why? (1)
b. What value do you
derive from this?
(1) c. What are the harmful effects of
artificial sweeteners? (1)
Ans:
a. Lakshmi
is able to handle diabetes better, because exercises activate the pancreases to
produce insulin. Exercise
keeps one fit and fine.
b. It is necessary to
lead a disciplined life.
c. Researches
have
shown that the
artificial sweeteners have harmful effect on the body because they are not
excreted easily.
8. Almelu did not
like the costlier brand
of dish washer because she was
not
satisfied by using
less quantity of the
dishwasher, so
she bought the cheaper
brand of dish washer and used large amounts of
it.
a. As a student of
chemistry what would you advise Almelu to use? (1)
b. Why? Explain.
(1)
c. What value did you impart to
Almelu?
(1)
Ans:
a. I would advise Almelu to use smaller quantities
of the costlier detergent.
b. Almelo was pouring detergents into
the drain.
These detergents
are not biodegradable. Branched detergents are highly
non-
degradable because the microbes cannot attack it. Straight chain detergents are being prepared these days to reduce the pollution problem. The costlier detergent contains straight chain hydrocarbon.
c. The value imparted
was to use environmentally friendly substances.
9. Water is a universal
solvent. But
alcohol also dissolves
most
of the substances soluble in water.
And also many more. Boiling point of
water is 100oC
and
that of alcohol is 80oC. The specific heat of water
is much higher than the specific heat of
alcohol.
a. List out three possible differences if
instead of water as the liquid in our body we had alcohol.
(3)
b. What value can you derive
from this special property of water
and
its innumerable uses in sustaining life on earth? (1) Ans:
a.
I. Even a small raise in temperature in the surroundings will raise the
temperature of the body because the
specific heat of
alcohol is much less than the specific heat of water. In order to cool
the
body more sweating will
take place.
II. As
there is less H bonding in alcohol it
will get evaporated faster. The
alcohol will be evaporated at such a fast rate that the liquid has to
be ingested always.
III. Ice which floats
on water helps aquatic life to exist even in winter
as water insulates heat from liquid below it to
go back to
the
surroundings. Solid alcohol
does not have such special
properties.
b. Praise is to
the
almighty that
has so thoughtfully given such
special properties
to water
and made it a liquid that could
sustain
life.
10. After cleaning the refrigerator thoroughly well, Rohit closed it and kept it
switched off
for two days. After
that on opening it, he got a foul smell. His neighbor advised him to keep a piece of
charcoal in
the fridge.
a. As a
student of chemistry explain why? (2)
b.
What value can be
drawn from this? (1)
Ans:
a. The charcoal piece adsorbs the foul
smelling gases. Eg: in a compost pit large
amount of charcoal can be
added to remove foul
smell.
b. Help
your
friends and
neighbours.
11.A stain of rust is there on your clothe. You are worried how to remove this
stain.
Shyam tells you to remove this
stain using ripened guava.
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a. Why?
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(2)
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b.
What is the value
Shyam is having when
doing this?
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(1)
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Ans:
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a. The rust is iron oxide. The oxalic acid in guava fruit dissolves iron
oxide.
b. Help
your
friends and
neighbours when you know some simple home techniques instead of
chemicals.
12. You are staying
near a fertilizer factory.
In
the middle of the night there is
a leakage of ammonia which is detected by its
smell. Within 10 minutes
you find the smell is intolerable.
.a. What would you do as first aid against this
gas spill accident for self and
neighbor? (2)
b. What value do you
derive from this?
(1)
Ans:
a. Ammonia is highly
soluble in water. It is detected by its characteristic fishy
odor. Hence keep
a wet kerchief on your nose to stop
inhaling the gas. Then help
your neighbours with your suggestion.
b.
Alertness
to tackle disasters for
society.
13. Pradeep had very high fever. He
was given strong antibiotics.
But after recovering from fever
he
was not able to digest food and was feeling too
weak. The grandmother who
lived in his neighborhood suggested him to
take lots of fruits and vegetables.
a.Why?
(1)
b. What is
the
remedy for this?
(1)
c. What was
the
value that Pradeep
had
by
taking fruits
and
vegetables? (1)
Ans:
a. Rise
in temperature denatures
the proteins in our body. The enzymes
which are also proteins get denatured. The body
has to regenerate these
enzymes.
Till then Pradeep will continue to
feel weak as the enzymes to digest food and for
respiration are destroyed due
to high temperature and change in
pH. Even after the enzymes are
regenerated, vitamins which act as prosthetic groups
in enzyme action are to
be
taken from an external
source.
b. By taking fruits
and
vegetables Pradeep is actually taking in vitamins.
c. He obeyed an elderly person’s
advice.
14. The chairman, Kandla
(Gujrat) port due to water
scarcity has decided to
desalinate sea water
to obtain potable water.
a. As a student of
chemistry which method will
be
suitable to use? (1)
b.
Discuss
the
method. (1)
c. What value have you inculcated in using
this method? (1)
Ans:
a) Reverse osmosis.
b) Discussed
c) Using less energy ie energy conservation
OR
a) Desalination using
evaporation using sun’s energy
b) Discuss
c) Using renewable
source of energy.
15.
An innovative washer
woman while washing a
copper miner’s clothes found that sand and similar dirt particle fell to
the
bottom, while the ore particles
stuck to the soapsuds and came to the
top. The washer
woman discussed this matter with a client who was a
chemist.
a. What is the reason for
this observation? (2)
b. What value do you
get from this
episode? (1)
Ans:
a. The miner’s
clothes had particles of CuS
/ Cu2S on
it. This adhered to
the froth and came up.
b. Keen
observation can lead to
great discoveries.
