# A container has a volume of 3 L and holds 2 mol of gas. If the container is expanded such that its new volume is 12 L, how many moles of gas must be injected into the container to maintain a constant temperature and pressure?

Aug 18, 2016

In the second situation, you expand (volume) 4 times ($\frac{12 L}{3 L} = 4$). The original mol was 2 and now you will need total 8 mol of gas.
Now you need to inject $8 - 2 = 6$ mol gas into your contained under new situation.