How To Define Enthalpy Of Any Thermodynamic System?

Enthalpy is a property of the system. There is no a specific definition of enthalpy, but it can be defined by using an equation. Enthalpy is “summation of internal energy and product of pressure and volume.” So we can write it as H = U + PV. Now in this equation “U” is energy so as PV. Ultimately enthalpy is also energy, so its SI unit is JOULE.

Wikipedia gives information about enthalpy like this “Enthalpy is a measurement of energy in a thermodynamic system. It gives an idea about the total heat content of the system”. so ultimately as my.smartiee Pant says:

Enthalpy is state function means point function. It is a property of the thermodynamic system. It doesn’t depend on thermodynamic path. Even if we take hundreds of thousands of paths to reach particular state Enthalpy of the system remains same.

Þ     Values of the Specific Heat of AIR:

As we all know ratio of specific heat can be given as Cp/Cv = ɣ   and  Cp – Cv = R ( R is specific gas constant for air )

now u can derive equation of Cp, which will be like Cp = ɣR /(ɣ-1)   & Cv = R /(ɣ-1). in above equation if u put ɣ = 1.4 and R = 0.287 kJ/ kg.K.

By putting these values in above equation, we have Cp = 1.004 & Cv = 0.717 ( note that these values of specific heat are only valid for air and only valid when the value of specific heat ratio is 1.4. This ratio is for standard air )