A gaseous compound is 30.4% nitrogen and 69.6% oxygen by mass. A 5.25-g sample of the gas occupies a volume of 1.00 L and exerts a pressure of 1.26 atm at -4.0°C. What is its molecular formula? (R = 0.08206 L • atm/K • mol)

Question

Quizplus · Accepted Answer

The molar mass of the gas is:(5.25 g) / (30.4% N) = 17.2 g/molThe empirical formula of the gas is:N: (17.2 g/mol) / (14.0 g/mol) = 1.23O: (17.2 g/mol) / (16.0 g/mol) = 1.08Multiplying by 2 to get whole numbers:N2O2The molecular formula is therefore N2O4.

A Gaseous Compound Is 30