Molar gas volume

The value $24\,\text{dm}^3\text{/mol}$ applies at RTP. Do not use it if the question supplies a different molar gas volume or different conditions.

Match the units to the molar gas volume: divide a volume in $\text{cm}^3$ by 1000 before using $24\,\text{dm}^3\,\text{mol}^{-1}$.

Convert $\text{cm}^3$ to $\text{dm}^3$ by dividing by 1000 before using the molar gas volume.