There is roughly 350 grams of nitrogen, N2, in the atmosphere for every 100 grams of oxygen, O2. Determine the approximate mole fraction of oxygen and nitrogen in Earth's atmosphere.

Answer 1

Moles N2 = 350 g x 1 mol/28 g = 12.5 mols N2

moles O2 = 100 g x 1 mol/32 g = 3.125 mols O2

Total moles = 12.5 + 3.125 = 15.625 mols

Mole fraction N2 = 12.5/15.625 = 0.80

Mole fraction O2 = 3.125/15.625 = 0.20