Describe the composition of atmosphere.
Atmosphere is a mixture of many discrete gases, water vapours, and dust particles.
i. Gases: Nitrogen (78%), Oxygen (21%) are the two major gases. The remaining 1% is composed of a number of gases like hydrogen-argon, ozone, helium, carbon dioxide, etc. oxygen is the most vital gas for sustaining life.
The various gases present in the atmosphere are as:
Constituent | Formula | Percentage by Volume |
|
Nitrogen |
N2 |
78.08 |
|
Oxygen |
O2 |
20.95 |
|
Argon |
Ar |
0.93 |
|
Carbon dioxide |
CO2 |
0.036 |
|
Neon |
Ne |
0.002 |
|
Helium |
He |
0.0005 |
|
Krypton |
Kr |
0.001 |
|
Xenon |
Xe |
0.00009 |
|
Hydrogen |
H2 |
0.00005 |
ii. Water Vapour: The amount of water vapour varies from place to place and time to time. It represents 2% of the air by volume. It is mostly found in the lower layers.
iii. Dust Particles: These are also found in the atmosphere in different sizes. The major sources of dust particle are deserts, lakes and dry rivers etc. These are found in the lower layers of the atmosphere. These are responsible for the formation of clouds, fog and smog.
