# What is the volume at 0 °C and 1 atm of a mixture that contains 4.0 g of methane and 2.0 g of helium?

Apr 15, 2014

The volume of the sample is 16.8 L.

1. Convert the mass of each gas to litres
2. Use the molar volume of each gas at STP to calculate its volume.
Moles of CH₄ = 4.0 g CH₄ × $\left(1 \text{mol CH₄")/(16.04" g CH₄}\right)$ = 0.25 mol CH₄
Moles of He = 2.0 g He × $\left(1 \text{ mol He")/(4.003" g He}\right)$ = 0.50 mol He
Volume of CH₄ = 0.25 mol CH₄ × $\left(22.414 \text{ L CH₄")/(1" mol CH₄}\right)$ = 5.6 L
Volume of He = 0.50 mol He × × $\left(22.414 \text{ L He")/(1" mol He}\right)$ = 11.2 L