(a) Calculate the mass of nitrogen present in a volume of $3000 \mathrm{~cm}^{3}$ if the gas is at $22.0^{\circ} \mathrm{C}$ and the absolute pressure of $2.00 \times 10^{-13}$ atm is a partial vacuum easily obtained in laboratories.
(b) What is the density (in $\mathrm{kg} / \mathrm{m}^{3}$ ) of the $\mathrm{N}_{2}$ ?