Evaluation of the entropy integral for an ideal gas

Since both Cp and R are constant for an ideal gas and Z = 1, integrating equation (16.39) produces 

This is the same result as would have been found by combining the equations pv = / .T and pv = constant, as we would expect. 

Integrating the enthalpy differential between starting and end conditions gives  

The final enthalpy following a frictionally resisted expansion is given by  

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