Question

A container has a volume of `4 L` and holds `3 mol` of gas. If the container is expanded such that its new volume is `36 L`, how many moles of gas must be injected into the container to maintain a constant temperature and pressure?

Answer 1

`27` moles

Explanation:

Let's use Avogadro's law:

`v_1/n_1 = v_2/n_2`

The number 1 represents the initial conditions and the number 2 represents the final conditions.

• Identify your known and unknown variables:

`color(red)("Knowns:"`
`v_1`= 4 L
`v_2`= 3L
`n_1`= 36 mol

`color(blue) ("Unknowns:"`
`n_2`

• Rearrange the equation to solve for the final number of moles:

`n_2=(v_2xxn_1)/v_1`

• Plug in your given values to obtain the final number of moles:

`n_2=(36cancelLxx3mol)/(4\cancel"L")` = `27 mol`