Exercise 7 | Properties of Gases

A gaseous mixture contains 35.0 bar of H2 (g), 32.3 bar of N2 (g) and 41.2 bar of Ar (g).

Calculate the mole fraction of each of these gases.

According to the Dalton’s law:

Ptot = PH2 + PN2 + PAr


Ideal gas equation:

PV = nRT

⇒ n = PVRT

 

By definition: mole fraction of 1 = x1 = n1ntot


mole fraction of H2:

xH2 = nH2ntot = PH2 VRT x RTPtot V = PH2 / Ptot

xH2 = 35.035.0 + 32.3 + 41.2 = 0.323


mole fraction of N2:

xN2 = nN2 / ntot = PN2 / Ptot

xN2 = 0.298


mole fraction of Ar:

xAr = nAr / ntot = PAr / Ptot

xAr = 0.380