The main components of air are nitrogen and oxygen. Normal air composition is: nitrogen (N2) accounts for about 78%, oxygen (O2) accounts for about 265,438+0%, rare gas accounts for about 0.939% (helium, neon, argon, krypton, xenon, radon), and carbon dioxide (CO2) accounts for about 0.0366.
There are other gases and impurities accounting for about 0.03%, such as ozone (O3), nitric oxide (NO), nitrogen dioxide (NO2), water vapor (H2O) and so on.
Gas use
Nitrogen is used as filling protective gas, liquid nitrogen can be used as refrigerant, and nitrogen is also one of the raw materials for synthetic ammonia industry. Living things need oxygen for aerobic respiration. Oxygen can be used as an accelerant and pure oxygen can be used for electric welding.
Rare gases can be used as protective gases, filling gases for colored lights and anti-aircraft lights. Carbon dioxide is the raw material of soda process in Hou Shi, and it is also the raw material of photosynthesis of green plants.
Carbon dioxide is also one of the main functions of fire extinguishers, and it is also a gas that can make limewater turbid. Its solid dry ice can also be used for artificial rainfall.