Chemistry
Answer
"Air is a mixture." This statement is supported by following three evidences:
- The composition of air is not fixed. It varies from place to place and from time to time.
- The components of air retain their individual properties.
- No energy exchange occurs when the components of air are mixed with each other.
Related Questions
Answer the questions put against each of the following constituents of air:
(a) Nitrogen : Explain its significance for plants and animals.
(b) Oxygen : What is the percentage proportion of oxygen in air? Why is oxygen called active air?
(c) Carbon dioxide : "Although carbon dioxide plays no role in respiration, all life would come to an end if there is no carbon dioxide in air." Support this statement with relevant facts.
(d) Water vapour : Explain its role in modifying the earth's climate.
Define the following terms:
(a) Pollutants
(b) Acid rain
(c) Global warming
(d) Smog
What is air pollution? What are the harmful effects of sulphur dioxide, nitrogen dioxide and hydrogen sulphide present in the air?
(a) What are the causes of air pollution?
(b) Suggest five measures to prevent air pollution.