Question

A mixture of 40.0 g of oxygen and 40.0 g of helium has a total pressure of 0.900 atm. Calculate partial pressure of each gas.

Answer 1

No. of moles of O₂ = \(\frac{\text {Given}\,\text{mass}}{\text {Mol.}\,\text {mass}}=\frac {40}{32} =1.25\,mol\)

No. of moles of He = \(\frac {40}{4} =10\,mol\)

Mole fraction of O₂ = \(\frac {1.25}{1.25 + 10}=\frac {1.25}{11.25} =\frac {1}9{}\)

Partial pressure of oxygen = 1/9 x 0.9 atm

= 0.1 atm