EXAMPLE PROBLEM $3$

Air is compressed from an initial state of $1$ bar and $250C$ to a final

state of $5$ bar and $250C$ by three different mechanically reversible

processes in a closed system:

$($a$)$ heating at constant volume followed by cooling at constant

pressure

$($b$)$ isothermal compression

$($c$)$ adiabatic compression followed by cooling at constant volume

Assume air to be an ideal gas with the constant heat capacities,

$CV=(\frac{5}{2})R$ and $Cp=(\frac{7}{2})R.$ Calculate the work required, heat

transferred, and the changes in internal energy and enthalpy of the air

for each process.