Question

three oxides of nitrogen N2O,NO2,N2O3 are mixed in a molar ratio of 3:2:1.find the average molar mass of gaseous mixture.

Answer 1

The molar ratio of gases N₂O, NO₂ and N₂O₃ are 3:2:1 respectively.
In a 100% mixture of gas,
the amount of N₂O will be 50.0%, of NO₂ will be 33.33% and of N₂O₃ will be 16.67% according to their molar ratios.
Now average molar mass of gaseous mixture =
$\frac{\mathrm{Molar}\mathrm{mass}\mathrm{of}{\mathrm{N}}_2\mathrm{O}\times \mathrm{percentage}\mathrm{of}{\mathrm{N}}_2\mathrm{O}+\mathrm{Molar}\mathrm{mass}\mathrm{of}{\mathrm{NO}}_2\times \mathrm{percentage}\mathrm{of}{\mathrm{NO}}_2+\mathrm{Molar}\mathrm{mass}\mathrm{of}{\mathrm{N}}_2{\mathrm{O}}_3\times \mathrm{percentage}\mathrm{of}{\mathrm{N}}_2{\mathrm{O}}_3}{100}$

$\mathrm{Average}\mathrm{molar}\mathrm{mass}\mathrm{of}\mathrm{gaseous}\mathrm{mixture}=\frac{44.013\times 50.0+46\times 33.33+76.01\times 16.67}{100}=50.01\mathrm{g}/\mathrm{mol}$