Question

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?

Answer 1

As the question is written, the number of moles can only be added is `=5mol`

Explanation:

Apply Avogadro's Law

`"Volume"/"Number of moles"= " Constant"`

At constant temperature and pressure

`V_1/n_1=V_2/n_2`

The initial volume is `=6L`

The initial number of moles is `n_1=5mol`

The final volume is `V_2=12L`

This is not a compression, it's an expansion

The final number of moles is

`n_2=V_2/V_1*n_1=12/6*5=10mol`

The number of moles to be added is

`=n_2-n_1=10-5=5mol`