# What's the volume in litres of 0.5mol of oxygen at STP?

$\text{11.2 L}$
$1$ mol of any gas at STP occupies $22.4$ litres of volume.
$0.5$ mol of oxygen gas will occupy
$0.5 \cancel{\text{mol" × "22.4 L"/(1 cancel"mol") = 11.2\ "L}}$