Question

A chamber containing 6 moles of O2 and 8 moles of H2 is placed in a container with a small leak in it. A small amount of escaping gas is collected in a container and found to have a total pressure of 4.8x10^-3 torr. What is the pressure of oxygen in the container?

Answer 1

This is a Graham's Law problem in effusion. The rate at which the gas escapes is inversely proportional to the square root of the molar mass, hence the heaviery O2 will escape slower, and the gas collected in the container will be enriched in H2.