For a gas having molar mass $M$, express specific heat at constant pressure in terms of heat capacity ratio.
My attempt:
using $ C_p - C_V = R $ and
$ \dfrac{C_p}{C_V} = \gamma $
$ C_p = \dfrac{R \gamma }{ \gamma - 1} $
But answer is $ C_p = \dfrac{R \gamma }{ M(\gamma - 1)} $
But from where this $M$ is coming from? Isn't specific heat independent of $M$?