The relative / density for helium of a gas mixture of nitrogen and sulfur dioxide SO2 is 15.

The relative / density for helium of a gas mixture of nitrogen and sulfur dioxide SO2 is 15. Determine the volume and mass fraction of nitrogen in the mixture.

N2, SO2 – mixture; D (He) = 15;

D (for helium) = M (substance) / M (helium);

Mr (He) = 4;

M (mixture) = 15 * 4 = 60 g;

In total, we have 1 mol of gases in the mixture: N2 (Mr = 28) x mol;

SO2 (Mr = 64) 1-x mol.

28 x + 64 * (1 – x) = 60;

28 x + 64 – 64 x = 60;

36 x = 4;

x = 0.11 mol N2 (11%);

m (N2) = 0.11 * 28 = 3 g;

ω (N2) = (3/60) * 100% = 5%.