# A container has a volume of 6 L and holds 5 mol of gas. If the container is compressed such that its new volume is 12 L, how many moles of gas must be released to maintain a constant temperature and pressure?

Aug 8, 2018

As the question is written, the number of moles can only be added is $= 5 m o l$

#### Explanation:

$\text{Volume"/"Number of moles"= " Constant}$

At constant temperature and pressure

${V}_{1} / {n}_{1} = {V}_{2} / {n}_{2}$

The initial volume is $= 6 L$

The initial number of moles is ${n}_{1} = 5 m o l$

The final volume is ${V}_{2} = 12 L$

This is not a compression, it's an expansion

The final number of moles is

${n}_{2} = {V}_{2} / {V}_{1} \cdot {n}_{1} = \frac{12}{6} \cdot 5 = 10 m o l$

The number of moles to be added is

$= {n}_{2} - {n}_{1} = 10 - 5 = 5 m o l$