One mole of a gas occupies 22.4 lit at N.T.P. Calculate the difference between two molar specific heats of the gas. J = 4200 J/kcal. 

(1) V = 22.4 litre = 22.4 × 10^–3 m³ , J = 4200 J/kcal

by ideal gas equation for one mole of a gas,

$$\begin{gathered} R=\frac{PV}{T}=\frac{1.013\times {10}^5\times 22.4\times {10}^{-3}}{273} \\ {C}_p-C_v=\frac{R}{J}=\frac{1.013\times {10}^5\times 22.4}{273\times 4200}=1.979 Kcal/kmol K \end{gathered}$$