The mass of nitrogen occupying a volume of 22.4.

Given:
V (N2) = 22.4 L
Vm = 22.4 l / mol

Find:
m (N2) -?

Solution:
1) Using the periodic system of D.I.Mendeleev, calculate the molar mass of nitrogen, which will be numerically equal to the relative molecular mass:
M (N2) = Mr (N2) = Ar (N) * 2 = 14 * 2 = 28 g / mol;
2) Calculate the amount of nitrogen substance (under normal conditions):
n (N2) = V (N2) / Vm = 22.4 / 22.4 = 1 mol;
3) Calculate the mass of nitrogen:
m (N2) = n (N2) * M (N2) = 1 * 28 = 28 g.

Answer: The mass of nitrogen is 28 g.