Question

A cylinder of compressed gas contains nitrogen and oxygen in the ratio $3:1$ by mole. If the cylinder is known to contain $2.5\times {10}^{4}g$ of oxygen, what is the total mass of the gas mixture?

Answer 1

Number of moles of oxygen in the cylinder
$=\frac{Massingram}{Molecularmassingram}=\frac{2.5\times {10}^4}{32}$
$=781.25$
Number of moles of $N_2=3\times 781.25=2343.75$
Mass of nitrogen in the cylinder $=2343.75\times 28$
$=65625g$
$=6.5625\times {10}^{4}g$
Total mass of the gas in the cylinder $=2.5\times {10}^4+6.5625\times {10}^4=9.0625\times {10}^{4}g$