An ideal gas with Cp $=(7/2)$R and Cv $=(5/2)$R undergoes the following reversible

changes in a series of nonflow processes:

$($a$)$ From an initial state of $70\backslash$deg F and $15$ psia, it is compressed adiabatically to $75$ psia.

$($b$)$ It is then cooled to $70\backslash$deg F at a constant pressure of $75$ psia.

$($c$)$ Finally, the gas is expanded isothermally to its original state.

Calculate Q$,$ WEC, $\backslash$Delta U$,$ and $\backslash$Delta H for each of the three processes and for the entire cycle.

Next, calculate Q$,$ WEC, $\backslash$Delta U$,$ and $\backslash$Delta H for exactly the same changes in state that you

computed above for $($a$)($c$),$ but now assuming that each process is irreversible with

an efficiency of $75\%$ compared to reversible operation. Specifically, if the reversible

process produces $10$ BTU of work, the irreversible process should produce $0\mathrm{.}75(10)$

$=7\mathrm{.}5$ BTU, and if the reversible process requires BTU kJ of work, the irreversible

process should require $10/0\mathrm{.}75=13\mathrm{.}33$ BTU. Use the exact same initial and final

states you already computed $($this will require nonzero heat flow in part $($a$)).$