Chapter 8, Problem 8RQ

Interpretation Introduction

Interpretation: The molar mass of the gas for the unknown molecular formula has to be determined.

Concept Introduction:

One method to determine the molar mass is from its measured density.

Other method to determine the molar mass is using Graham’s law of effusion.

Graham’s law of effusion states that the relative rates of effusion of two gases at the same temperature and pressure are given by the inverse ratio of the square roots of the masses of the gas particles.

Graham’s law of effusion can be given as,

$\frac{\text{Rate}\text{of}\text{effusion}\text{for}\text{gas}\text{1}}{\text{Rate}\text{of}\text{effusion}\text{for}\text{gas}\text{2}}\text{=}\frac{\sqrt{{\text{M}}_{\text{2}}}}{\sqrt{{\text{M}}_{\text{1}}}}$

Where ${\text{M}}_{\text{1}}$ and ${\text{M}}_{\text{2}}$ are molar masses.