# A container has a volume of 5 L and holds 2 mol of gas. If the container is expanded such that its new volume is 12 L, how many moles of gas must be injected into the container to maintain a constant temperature and pressure?

May 18, 2017

The number of moles is $= 2.8 m o l$

#### Explanation:

We apply Avogadro's Law (Temperature and Pressure constant)

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

The initial volume is $= 5 L$

The initial number of moles is $= 2 m o l$

The final volume is $= 12 L$

The final number of moles is

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

$= \frac{12}{5} \cdot 2 = 4.8 m o l$

The number of moles to be injected is

$= 4.8 - 2 = 2.8 m o l$