#### Answer

The molar volume of gas at STP is 22.4 L.

#### Work Step by Step

Using ideal gas law, the volume occupied by 1 mol of gas at 0°C and 1 atm can be calculated.
At standard temperature and pressure, the volume occupied by 1 mol of gas is called molar volume of an ideal gas.
According to ideal gas law,
PV=nRT.
$V = \frac{nRT}{P}$
$V = \frac{1 mol \times .0821 \frac{L atm}{Kmol} \times 273 K}{1 atm}$
Solve using a calculator
$V = 22.4$
Therefore the molar volume of gas at STP is 22.4 L.