A mixture of carbon dioxide and an unknown gas was allowed to effuse from a container. The carbon dioxide took 1.25 times as long to escape as the unknown gas. Which one could be the unknown gas?

Question

Quizplus · Accepted Answer

According to Graham's law of effusion, the rate of effusion is inversely proportional to the square root of the molar mass of the gas. Since CO2 took 1.25 times as long to effuse, the unknown gas must have a lower molar mass than CO2. CO (carbon monoxide) has a molar mass of 28 g/mol, which is less than CO2's molar mass of 44 g/mol, making it a plausible candidate.

A Mixture of Carbon Dioxide and an Unknown Gas Was