# How many moles of a gas would occupy 157 L at 132 kPa and -16.8°C?

First convert the temperature to kelvin: $273.15 - 16.8 = 256$ $K$. The Ideal Gas Law says $P V = n R T$ (where $R = 8.314$ L kPa K^−1 mol^−1). Rearranging, $n = \frac{P V}{R T} = \frac{132 \cdot 157}{8.314 \cdot 256} = 9.74$ $m o l$.