A mixture of xenon and nitrogen gases, at a total pressure of 749 mm Hg, contains 16.8 grams of xenon and 5.54 grams of nitrogen. What is the partial pressure of each gas in the mixture?

Answer 1

Xe + N₂ ... P_total = 749 mm Hg

Question: partial pressure of each gas.

Partial pressure of a gas = mole fraction of that gas x total pressure (Raoults law)

moles Xe = 16.8 g x 1 mol Xe / 131 g = 0.128 moles Xe

moles N2 = 5.54 g N2 x 1 mol N2 / 28 g = 0.198 moles N2

Total moles of gas = 0.128 moles x 0.198 moles = 0.326 moles

Mole fraction Xe = 0.128/0.326 = 0.393

Mole fraction N2 = 0.198/0.326 = 0.607

Partial pressure of Xe = 0.393 x 749 mm Hg = 294 mm Hg

Partial pressure of N2 = 0.607 x 749 mm Hg = 455 mm Hg