(N/A) If the amount of substance is specified in terms of moles $\mu$,instead of mass $m$ in $kg$,we can define heat capacity per mole of the substance by:
$C = \frac{1}{\mu} \frac{\Delta Q}{\Delta T}$
where $C$ is known as the molar specific heat capacity of the substance. $C$ depends on the nature of the substance and its temperature.
The $SI$ unit of molar specific heat capacity is $J \cdot mol^{-1} \cdot K^{-1}$.
We can define molar specific heat for gases in two ways:
$(i)$ Molar specific heat at constant pressure $(C_P)$: If the gas is held under constant pressure during the heat transfer,the molar specific heat capacity is called the molar specific heat capacity at constant pressure,denoted by $C_P$.
$(ii)$ Molar specific heat at constant volume $(C_V)$: If the volume of the gas is maintained constant during the heat transfer,the corresponding molar specific heat capacity is called the molar specific heat capacity at constant volume,denoted by $C_V$.