Question

If `2 L` of a gas at room temperature exerts a pressure of `72 kPa` on its container, what pressure will the gas exert if the container's volume changes to `7 L`?

Answer 1

The new pressure is `21 kPa`

Explanation:

Let's begin by identifying our known and unknown variables.

The first volume we have is `2` L, the first pressure is `72kPa` and the second volume is `7`. Our only unknown is the second pressure.

The answer can be ascertained by using Boyle's Law:

All we have to do is rearrange the equation to solve for the final pressure.

We do this by dividing both sides by `V_2` to get `P_2` by itself like this:
`P_2=(P_1xxV_1)/V_2`

Plug in your given values to get your final pressure:

`P_2=(72\kPa xx 2\ cancel"L")/(7\cancel"L")` = `21kPa`