Question

calculate the number of molecules of methane which will occupy the same volume as 10 molecules of CO2 at STP?

Answer 1

One mole of a gas at STP occupies 22.4 l. Which means 6.022*10²³ molecules of any gas occupy same volume at STP.
Or equal number of molecules of any gas occupy same volume at STP.

So 10 molecules of methane will occupy same volume as 10 molecules of CO₂,$\frac{22.4\times 10}{6.022\times {10}^{23}}=37.19\times {10}^{-23}\mathrm{l}$