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Environmental

environmental chemistry for class 11 cbse syllabus

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Environmental

  1. 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 
  2. 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. 3. Pollutant       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. 4. Atmospheric pollution    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. 5. Tropospheric pollution   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. 6. GLOBAL WARMING   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. 7. Greenhouse effect   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. 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. 9. PrePared by K.JaNardHaN aCHaryULU PGT (CHeMISTry) KV KaNCHaNbaGH Hyderabad-40
  10. 10. PrePared by K.JaNardHaN aCHaryULU PGT (CHeMISTry) KV KaNCHaNbaGH Hyderabad-40

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