Question

Describe the composition of the atmosphere and mention the uses of its constituent gases.

Answer 1

Atmosphere is the layer of air that surrounds the Earth. The molecules of the gases are held close to the surface by the gravitational pull of the Earth. The atmosphere comprises the following components:

1. Gases
i) Nitrogen,which is the most abundant gas in the atmosphere and constitutes 78% of the air.
ii) Oxygen constitutes 21% of the air.
iii) Ozone, Hydrogen, Argon and Helium constitute 1% of the air.

2. Water vapour

3. Dust particles

The uses of the above mentioned constituent gases are as follows:

i) Nitrogen: It is used to make fertilisers and dyes. It is also used as a refrigerant as well as to store food.
ii) Oxygen: All living organisms use oxygen for breathing and hence, it is important for the survival of all life forms on Earth.
iii) Carbon dioxide: It is used by plants for producing energy through photosynthesis.
iii) Hydrogen helps in the formation of water.
iv) Ozone protects the Earth from the harmful ultraviolet rays of the Sun.
v) Argon is used for arc welding.
vi) Helium is used as a light weight aircraft fuel.