Exercise 7 | Properties of Gases

According to the Dalton’s law:

P_tot = P_H2 + P_N2 + P_Ar


Ideal gas equation:

PV = nRT

⇒ n = $\frac{\mathrm{PV}}{\mathrm{RT}}$

By definition: mole fraction of 1 = x₁ = $\frac{{\mathrm{n}}_1}{{\mathrm{n}}_{\mathrm{tot}}}$

mole fraction of H₂:

x_H2 = $\frac{{\mathrm{n}}_{\mathrm{H}2}}{{\mathrm{n}}_{\mathrm{tot}}}$ = $\frac{{\mathrm{P}}_{\mathrm{H}2} \mathrm{V}}{\mathrm{RT}}$ x $\frac{\mathrm{RT}}{{\mathrm{P}}_{\mathrm{tot}} \mathrm{V}}$ = P_H2 / P_tot

x_H2 = $\frac{35.0}{35.0 + 32.3 + 41.2}$ = 0.323

mole fraction of N₂:

x_N2 = n_N2 / n_tot = P_N2 / P_tot

x_N2 = 0.298

mole fraction of Ar:

x_Ar = n_Ar / n_tot = P_Ar / P_tot

x_Ar = 0.380