Why a gas has two principle specific heat capicities? What is the significance of Cp-Cv & Cp/Cv where symbols have usual meaning.

                                                                                                                               

Gas has two specific heat capacities because it has two variables pressure and volume sensitive. These are significant in case of gas. We can assume one of them is fixed when we supply heat.

If volume of the gas is constant and heat is supplied. Then we define specific heat is called specific heat at constant volume (C_V).

Similarly at constant pressure specific heat capacity is defined as (C_P).

Significance of (C_P – C_V) and (C_P / C_V).

C_P – C_P  = R, 

R = Gas constant.

For any gas (C_P – C_V) is fixed that is gas constant.

Ration of the C_P/C_V gives the some constant value.

It determines the type of gas like monatomic, diatomic etc.