Use R=8.3 J/mol-K wherever required.

Use $\mathrm{R}=8.3 \mathrm{~J} / \mathrm{mol}-\mathrm{K}$ wherever required.

Find the number of molecules in $1 \mathrm{~cm}^{3}$ of an ideal gas at $0^{\circ} \mathrm{C}$ and at a pressure of $10^{-5} \mathrm{~mm}$ of mercury.