# A container has a volume of #3 L# and holds #2 mol# of gas. If the container is expanded such that its new volume is #8 L#, how many moles of gas must be injected into the container to maintain a constant temperature and pressure?

##### 2 Answers

The number of moles to be injected is

#### Explanation:

Apply Avogadro's Law

At constant temperature and pressure

The initial volume is

The initial number of moles is

The final volume is

The final number of moles is

The number of moles to be injected is

#### Explanation:

Assume the gas is ideal

Let

Now, from ideal gas equation,

Let

Now, from ideal gas equation,

Dividing (2) by (1) as follows

Thus,