Chapter 1.2, Problem 14P

Calculate the mass of a mole of dry air, which is a mixture of ${\text{N}}_{\text{2}}\left(\text{78\% by volume}\right){\text{, O}}_{\text{2}}\left(\text{21\%}\right)\text{,}$ and $\text{argon }\left(\text{1\%}\right)\text{.}$