[tex]V=5\ l\\ V_m=22,42\ l/mol \\ \nu=\frac{m}{M}=\frac{V}{V_m} \\ \Rightarrow m=\frac{M \cdot V}{V_m} \\ M=1 \ g/mol \\ \Rightarrow m=\frac{1\ g/mol \cdot 5\ l}{2,42 \ l/mol}=2,066\ g \\ \rho=\frac{m}{V}=\frac{2,066\ g}{5\ l} \\ \Rightarrow \boxed{\rho=0,413\ g/dm^3}[/tex]
