# What is the molar mass of a gas if 8.482 grams of the gas will occupy 2.500 liters of space at STP?

Feb 10, 2016

Approx $70 - 80$ $g \cdot m o {l}^{-} 1$.

#### Explanation:

At STP $1$ mole of ideal gas occupies a volume of $22.41$ $L$.

We assume that the unknown gas behaves ideally, so that the molar quantity is $\frac{2.500 \cdot L}{22.41 \cdot L \cdot m o {l}^{-} 1}$ $=$ $0.1116$ $m o l$.

But this molar quantity has a mass of $8.482$ $g$.

So $\text{Molar mass}$ $=$ $\frac{8.482 \cdot g}{0.1116 \cdot m o l}$ $=$ $76.00$ $g \cdot m o {l}^{-} 1$.