From this value, and assuming that air contains only molecular nitrogen and molecular oxygen gases, calculate the mass percent of N2 and of O2 in air.

60% and 52%

Explanation:

At Standard temperature and volume (STP)

Volume of gas = 22.4L

Density = mass/volume

⇒ 1.186 =

= 26.566g

Molar mass of O2 = 16g/mole

Molar mass of N2 = 14g/mol

% mass of O2 = 16/26.566 × 100

= 60.23 %

% mass of N2 = 14/26.566 × 100

= 52.70 %

(Check: totl composition of gas is 100% i.e 60 + 52 %)