Which gas below has the largest number of moles at STP?

a.) 22.4L Ne

b.) 20L Ar

c.) 2.24L Xe

d.) They all have the same number of moles.

a.) 22.4 L Ne.

Explanation:

It is known that every 1.0 mol of any gas occupies 22.4 L.

For the options:

22.4 L Ne:

It represents 1.0 mol of Ne.

20 L Ar:

using cross multiplication:

1.0 mol occupies → 22.4 L.

? mol occupies → 20 L.

The no. of moles of (20 L) Ar = (1.0 mol) (20 L) / (22.4 L) = 0.8929 mol.

2.24 L Xe:

using cross multiplication:

1.0 mol occupies → 22.4 L.

? mol occupies → 2.24 L.

The no. of moles of (2.24 L) Xe = (1.0 mol) (2.24 L) / (22.4 L) = 0.1 mol.

So, the gas that has the largest number of moles at STP is: a.) 22.4 L Ne.