# If 4 moles of gas are added to a container that already holds 1 mole of gas, what happens to the pressure inside the container due to the change in the amount of gas?

Sep 12, 2016

The pressure increases fivefold.

#### Explanation:

At constant volume, and constant temperature, pressure is proportional to the number of molecules, and thus to the number of moles.

We can see this immediately from the Ideal Gas equation:

i.e. ${P}_{1}$ $=$ $\frac{n \times R \times T}{V}$

${P}_{2}$ $=$ $\frac{\left(n + 4 n\right) \times R \times T}{V}$ $=$ $5 {P}_{1}$