# A 4.0 L sample of hydrogen gas at 700 mmHg would occupy what volume at 250 mmHg?

Jul 18, 2016

$\textcolor{\in \mathrm{di} g o}{\text{That sample of hydrogen would occupy a new volume of 11L}}$

#### Explanation:

We can calculate the answer using Boyle's Law which shows that there is an inverse relationship between pressure and volume as long as the temperature and number of moles remain constant.

The equation we use is:

$\textcolor{h o t \pi n k}{\text{Let's write down what we know and what we don't know based}}$
$\textcolor{h o t \pi n k}{\text{on the information given to us:}}$

The first volume has a value of $4.0$ L, the first pressure is $700 m m H g ,$ and the second pressure is $250 m m H g$. Our only unknown is the second volume.

All we have to do is rearrange the equation to solve for ${V}_{2}$

We do this by dividing both sides by ${P}_{2}$ to get ${V}_{2}$ by itself:
${V}_{2} = \frac{{P}_{1} \times {V}_{1}}{P} _ 2$

Now all we have to do is plug in the given values:
${V}_{2} = \left(700 \setminus \cancel{\text{mmHg" xx 4.0\"L")/(250cancel"mmHg}}\right)$ = $11 L$