It is desired to increase the volume of 800 cmଷ  of a gas by 20% keeping the pressure constant. To what temperature should the gas be heated, if the initial temperature is 22°C

Given data is;

Initial, temperature, ${\mathrm{T}}_1=22+273=295\mathrm{k}$

Initial volume ${\mathrm{V}}_1=800 {\mathrm{cm}}^3$

Final volume, ${\mathrm{V}}_2={\mathrm{V}}_1+20\% \mathrm{of} {\mathrm{V}}_1$

${\mathrm{V}}_2=800+\frac{800\times 20}{100}=960 {\mathrm{cm}}^3$

According to Charles’s law,

$\frac{{\mathrm{V}}_1}{{\mathrm{T}}_1}=\frac{V_2}{T_2}=\frac{800}{295}=\frac{960}{T_2}$

$\Rightarrow {\mathrm{T}}_2=\frac{960\times 295}{800}=354\mathrm{K}$

Final temperature in °C = 354  −273

${\mathrm{T}}_2=81°\mathrm{C}$