What is the molecular weight of air?


Air is a combination of a few gasses, where the two most prevailing parts in dry air are 21 vol% oxygen and 78 vol% nitrogen, Argon: 0.934% and Carbon dioxide: 0.03%

Since both of these components are diatomic in air – O2 and N2, the molar mass of gasses are given by

The nuclear/atomic loads are:

Nitrogen: 14.0067 x 2 = 28.0134 g/mol (recall it is N2)
Oxygen: 15.9994 x 2 = 31.9988 g/mol (recall it is 02)
Argon: 39.948 g/mol
Carbon dioxide: 44.01 g/mol

Weight of each gas by knowing the rate

Nitrogen: (78.084/100) x 28.0134 = 21.8739 g/mol
Oxygen: (20.946/100) x 31.9988 = 6.7025 g/mol
Argon: (0.934/100) x 39.948 = 0.373 g/mol
Carbon dioxide: (0.03/100) x 44.01 = 0.013203 g/mol

Add every one of the qualities we get,

21.8739 + 6.7025 + 0.373 + 0.013203 = 28.96 g/mol. This is the atomic load of the air.

Final Answer: Hence, the molecular weight of air is 28.96 g/mol.