Question

A container has a volume of `3 L` and holds `18 mol` of gas. If the container is expanded such that its new volume is `6 L`, how many moles of gas must be injected into the container to maintain a constant temperature and pressure?

Answer 1

`36 "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(purple)("Knowns:"`
`v_1`= 3 L
`v_2`= 6 L
`n_1`= 18 mol

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

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

`n_2=(v_2xxn_1)/v_1`

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

`n_2=(6cancelLxx18mol)/(3\cancel"L")` = `36 mol`