CHAPTER 1 • 5 MARKS

Concerns about Our Environment

Study atmospheric changes, greenhouse effect, ozone depletion, pollution and sustainable energy choices.

Topics in this chapter

  1. Atmosphere and its importance
  2. Greenhouse effect and global warming
  3. Ozone layer and its depletion
  4. Air pollutants and acid rain
  5. Conventional and non-conventional energy
  6. Environmental protection and sustainable development

Key learning points

✓ Greenhouse gases trap outgoing heat and raise Earth’s average temperature.

✓ Ozone in the stratosphere absorbs harmful ultraviolet radiation.

✓ Acid rain mainly results from oxides of sulphur and nitrogen.

✓ Renewable energy reduces dependence on exhaustible fossil fuels.

Important equations and relations

C + O₂ → CO₂S + O₂ → SO₂2SO₂ + O₂ → 2SO₃SO₃ + H₂O → H₂SO₄

Multiple-choice questions

1. Which gas is mainly associated with the greenhouse effect?
  1. Oxygen
  2. Carbon dioxide
  3. Hydrogen
  4. Helium

Answer: B — Carbon dioxide

2. The ozone layer mainly absorbs:
  1. Infrared rays
  2. Ultraviolet rays
  3. Radio waves
  4. Sound waves

Answer: B — Ultraviolet rays

3. Acid rain commonly contains:
  1. Sulphuric and nitric acids
  2. Hydrochloric acid only
  3. Acetic acid
  4. Carbonic acid only

Answer: A — Sulphuric and nitric acids

Very short-answer questions

  1. What is a greenhouse gas?
  2. Name one renewable source of energy.
  3. Which atmospheric layer contains most ozone?

Short-answer questions

  1. Explain how acid rain is formed.
  2. Differentiate between renewable and non-renewable energy sources.

Long-answer question

  1. Discuss major environmental concerns caused by human activities and suggest preventive measures.