# A student collects a sample of gas and finds that 1.01 g of the gas will fill a container with a volume of 0.225 L at STP. What is the molar mass of the gas?

Jan 23, 2016

$M M = 101 \frac{g}{m o l}$

#### Explanation:

At STP, we know that the molar volume of a gas is $22.42 \frac{L}{m o l}$, therefore, now we can calculate the number of mole of the gas from its volume $V = 0.225 L$ at STP.

$\implies n = 0.225 \cancel{L} \times \frac{1 m o l}{22.42 \cancel{L}} = 0.01 m o l$

From the number of mole and the mass of the sample ($m = 1.01 g$) we can find the molar mass of the gas:

$n = \frac{m}{M M} \implies M M = \frac{m}{n} = \frac{1.01 g}{0.01 m o l} = 101 \frac{g}{m o l}$