# A container has a volume of 4 L and holds 5 mol of gas. If the container is compressed such that its new volume is 3 L, how many moles of gas must be released to maintain a constant temperature and pressure?

##### 1 Answer
May 27, 2018

$1.25$ moles of gas

#### Explanation:

At constant pressure, we can use Avogadro's law, which states that,

$V \propto n$ or ${V}_{1} / {n}_{1} = {V}_{2} / {n}_{2}$

So, we get:

$\frac{4 \setminus \text{L")/(5 \ "mol")=(3 \ "L}}{n} _ 2$

n_2=(5 \ "mol")/(4color(red)cancelcolor(black)"L")*3color(red)cancelcolor(black)"L"

$= 3.75 \setminus \text{L}$

So, the number of moles that have to be released is:

$5 \setminus \text{mol"-3.75 \ "mol}$

$= 1.25 \setminus \text{mol}$