environmental chemistry for class 11 cbse syllabus

1. ENVIRONMENTAL CHEMISTRY
OBJECTIVES
At the end of this session all will be able to
Understand the meaning of environmental
chemistry

Define Atmospheric pollution, reasons for Global
warming,Green house effect and Acid Rain
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2. Environmental chemistry deals with the study of
the origin, transport, reactions,effects and fates of
chemical species in the environment
ENVIRONMENTAL Pollution

It is the effect of undesirable changes in our
surroundings that have harmful effects on
plants,animals & human beings


3. Pollutant
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

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Pollutant – A substance ,which causes pollution
is known as pollutant
Pollutants can be in solid,liquid or gas
Pollutants may be degradable or partially
degradable
Eg – discarded vegetables,DDT,plastic
materials,many chemicals,nuclear wastes
In the process of environmental

4. Atmospheric pollution


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The atmosphere that surrounds the earth is not
of the same thickness at all heights & its
pollution is studied under the heads of
Troposphere and Stratosphere
Troposphere – The lowest region of
atmosphere in which life exists and extends up
to 10km
Stratosphere- It is a turbulent dusty zone
contains air, water vapor and clouds

5. Tropospheric pollution

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Due to the presence of undesirable solid or
gaseous particles in the air, tropospheric
pollution occurs
Major gaseous air pollutants are -
Oxides of S,N,C,H₂S,hydrocarbons and Ozone

Particulate pollutants are-
Dust,mist,smoke and smog

6. GLOBAL WARMING

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About 75% of the solar energy reaching the
earth is absorbed by the earths surface , which
increases its temperature, The rest of the heat
radiates back to the atmosphere
Some of the heat is trapped by the gases such
as CO₂,CH₄,O₃,CFCs and water vapor ,they
add to the heating of the atmosphere causing
global warming

7. Greenhouse effect
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In a greenhouse , visible light passes through
the transparent glass and heats up the soil and
the plants, the warm soil and plants emit
infrared rays, it partly reflects and partly absorb
these radiations, this mechanism keeps the
energy of the sun trapped in the greenhouse
If the amount of carbon dioxide crosses the
delicate proportion of 0‧03 % ,the natural green
house balance get disturbed

8. ACID RAIN

When the pH of the rain water drops below 5‧6,it is
called acid rain․ Oxides of sulphur and nitrogen
which are acidic in nature blown by wind along
with solid particles in the atmosphere and
finally settle down on the ground as deposition
in water is called Acid rain․ It is harmful for
agriculture because it dissolves and washes
away nutrients needed for their growth․It
causes respiratory ailments in human beings․

9. PrePared by
K.JaNardHaN aCHaryULU
PGT (CHeMISTry)
KV KaNCHaNbaGH
Hyderabad-40

10. PrePared by
K.JaNardHaN aCHaryULU
PGT (CHeMISTry)
KV KaNCHaNbaGH
Hyderabad-40