Chemistry Pressure

Question

At a certain temperature, a mixture of 2 gases, 11.2 g of oxygen and 104.75 of krypton exert a total pressure of 4.25 atm. What is the partial pressure of each gas in mm Hg?

Answer 1

The partial pressure exerted by each gas is proportional to the mole fraction of each gas.

moles of O2 = 11.2 g O2 x 1 mole/32 g = 0.35 moles

moles Kr = 104.75 g x 1 mol/83.8 g = 1.25 moles

Total moles = 1.25 + 0.35 = 1.60 moles

mole fraction O2 = 0.35/1.60 = 0.219

mole fraction Kr = 1.25/1.60 = 0.781

Partial pressure O2 = 0.219 x 4.25 atm = 0.931 atm

Partial pressure Kr = 0.781 x 4.25 atm = 3.32 atm