Environmental Chemistry: Solved Exercise and Think-Tank

Question 2: Give short answers.

I. List main sources of acid rain.

Answer.

1. Sulphur dioxide from power stations and factories 🏭

2. Nitrogen oxides from exhaust fumes of automobiles

3. Lightening during thunderstorm

ii. List four human activities which contribute to air pollution.

Answer.

I. Incomplete burning of fossil fuels ( coal, petroleum and ntural fas) from motor vehicles, factories and powe plants.

2. Incineration

3. CFCs used for cleaning circuit, as refrigerants in fridges, air conditioner etc, as propellants in aerosol sprays ( air fresher, hairspray, deodorants, spray paints).

4. Photocopier machines, television, microwave and other electrical equipments.

iii. What is the importance of stratospheric ozone?

Answer. Stratosphere contains maximum amount of ozone gas (about 10 ppm) also known as ozone layer. Prsrsnce of ozone asaves us from harmful effects of ultra voilet radiation coming directly from sun. Ozone layer also protects the living things on earth from ultra voilet radiation from sun.

iv. What is the role of automobile in air pollution?

Answer. Nearly half of air pollution is result of burning of fossil fuels such coal, petroleum and natural gas from cars 🚗 and other vehicles. Burning of fossil fuels releases carbon monoxide (CO), nitrogen oxides (NO, NO2), and sulphur oxides ( SO2, SO3).

v. Define atmosphere.

Answer. The envelope of gases and water vapors surrounding the planet earth is called atmosphere.

Question 3: Explain temperature variations in stratosphere and troposphere..

Answer. Troposphere starts from earth surface and extends upto 12 km high. On earth surface, average temperature is 17 oC. As altitude increases in troposphere, temperature decreases from 17 oC to -55 oC. That means for every 1km increase in altitude, air gets 6.5 oC cooler.

The stratosphere extends from 12 to 50 km above earth 🌎 surface. In this layer, as altitude increases, temperature also increases, from -55oC to -5oC.. Here temperature increases because ozone absorb ultra voilet radiation and converts it into heat.

Question 4: List the components of stratosphere and troposphere.

Answer. Troposphere contains most of the mass (75 -80%) of atmosphere. This layer of atmosphere mainly contains nitrogen gas, oxygen gas, water vapours and many other gases. Nearly all dust particles and water 💧 vapour are there. All weather occur in this layer. We all live in this layer of atmosphere.

Stratosphere also composed of mainly nitrogen and oxygen gases. This layer also contains water vapors and blanket of ozone layer that protects us from harmful radiation.

Question 5: Describe sources of air pollution.

Question 6: Describe acidic rain and its effects.

Question 7: Describe ozone depletion and its effects.

Question 8; Describe global warming.

Question 9: Differentiate between troposphere and stratosphere.

Question 10: Explain ozone formation.

Question 11: Why global warming is often referred to as green house effect?

Question 12: There is scientific evidence that CFCs contribute to the depletion of ozone, why?

Question 13: Sulphur dioxide is a common pollutant from burning coal. State two effects caused by this pollutant.

Think Tank 🤔

Question 14: Dibenzothiophene (C12H8S) is common Sulphur containing compound of coal.It is responsible for acid rain. Elaborate this statement.

Question 15; There have been attempts to remove sulphur from coal before it is burned. Illustrate

Question 16: Examin the option there are some ways to reduce pollution caused by cars.

Question 17: Certain human activities are responsible for a significant increase in greenhouse effect, argue.

Question 18: As a global citizen, how can you play a part to reduce the pollution at a personal level? Argue.

Question 19: Compare and contrast between stratosphere and troposphere.

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