🤓 Based on our data, we think this question is relevant for Professor Nathanson's class at UW-MADISON.

A gas of unknown molecular mass was allowed to effuse through a small opening under constant-pressure conditions. It required 115 s for 1.0 L of the gas to effuse. Under identical experimental conditions it required 31 s for 1.0 L of O_{2} gas to effuse.

Calculate the molar mass of the unknown gas. (Remember that the faster the rate of effusion, the shorter the time required for effusion of 1.0 L; that is, rate and time are inversely proportional.)

We use **Graham's Law of Effusion** to solve this problem:

Where **M is the Molar mass. **

We do not have the given rates so we would have to modify the equation to fit the given values.

Now the rate is si given as below:

Effusion