Nitrogen gas has a molar mass of about 28.0134 g/mol. Then we have a starting amount of
(42 g) / (28.0134 g/mol) ≈ 1.4993 mol
of N₂.
At standard temperature and pressure, one mole of an ideal gas occupies a volume of about 22.4 L. Then 42 g, or 1.4993 mol, of N₂ takes up
(1.4993 mol) × (22.4 L/mol) ≈ 33.6 L