Question #20b20

One mole of gas will have number of molecules $= 6.022 \times {10}^{23} \text{ molecules}$
Also standard molar volume of a gas at STP is $= 22.4 l$
Using above two relationships the occupied volume per molecule of gas at STP (which is not same as the volume of a molecule)$= \frac{22.4 \times {10}^{3}}{6.022 \times {10}^{23}} \approx 3.72 \times {10}^{-} 20 c {m}^{3}$