Question

A 10.0-liter flask contains 1.013 grams of oxygen and .572 grams of carbon dioxide at 180C. What are the partial pressures of oxygen and carbon dioxide? What is the total pressure? What is the mole fraction of oxygen in the mixture?

Answer 1

P tot = 0.1065 atm

The mole fraction of oxygen in the mixture : 0.709

Further explanation

Given

10 L flask

1.013 g O₂

572 g CO₂

T = 18 °C = 291 K

Required

P O₂ and P CO₂

Solution

Dalton Law's of partila pressure

P tot = P₁ + P₂ + ..Pₙ

From ideal gas Law :

`\tt P_(O_2)=((1.013)/(32)* 0.082* 291 )/(10)\\\\P_(O_2)=0.0755~atm`

`\tt P_(CO_2)=((0.572)/(44)* 0.082* 291)/(10)\\\\P_(CO_2)=0.031~atm`

P tot = P O₂ + P CO₂

P tot = 0.0755 + 0.031

P tot = 0.1065 atm

The mole fraction of O₂ :

`\tt P_(O_2)=X_(O_2)* P_(tot)\\\\X_(O_2)=(P_(O_2))/(P_(tot))\\\\X_(O_2)=(0.0755~atm)/(0.1065~atm)\\\\X_(O_2)=0.709`