A certain sample of gas has a volume of  $0.2$ litre measured at 1 atm pressure and $0°\mathrm{C}$. At the same pressure but $273°\mathrm{C},$its volume will be:  

. Since pressure is the same, it is Charle' s law

                        $\begin{array}{l}{\text{V}}_1=0.2\mathrm{L}, {\mathrm{T}}_1=0+273=273\mathrm{K};\\ v_2=? {\text{T}}_2=273+273= 546\mathrm{K}.\\ \frac{\mathrm{V}1}{{\mathrm{T}}_1}=\frac{{\mathrm{V}}_2}{{\mathrm{T}}_2}; {\mathrm{V}}_2=\frac{{\mathrm{V}}_1}{{\mathrm{T}}_1}\times {\mathrm{T}}_2\\ {\mathrm{V}}_2=\frac{0.2\mathrm{L}\times 546\mathrm{K}}{273\mathrm{K}}=0.4\mathrm{L}\end{array}$