Help answering this question please

Question

If 20.3 mol of Ne gas occupies 151.7 L, how many mol of Ne would occupy 774.4 L under the same temperature and pressure? Record your answer in scientific notation using 3 significant figures.

Answer 1

This is a variation on the combined gas law. While we generally don't include the moles (n) we can because P ∝n.

So, P₁V₁/n₁T₁ = P₂V₂/n₂V₂

We're told that the P & T are constant, so they cancel and we can rearrange to solve for (isolate) n₂:

n₂ = n₁V₂/V₁. This gives an answer, to 3 sig figs, of 104 moles