Problem Two $[25(10-15)]$

$\frac{w_{\text{B}\text{e}\text{e}}}{}=w_{c}ct=$ Hact

A gas at $T_1=400K$ and $P_1=15$ bar is expanded through an adiabatic, steady$-$state turbine to $P_2=$

$8$ bar and $T_2=300K.$ Given for the gas:

$H_1^R=-500J*mol{e}^{-1}$;$,S_1^R=-5J*T^{-1}*mol{e}^{-1}$;$,H_2^R=0$;$S_2^R=0$;$,C_p^{ig}=30J*mol{e}^{-1}.$

a$)$ Find the actual work delivered by the turbine, $(W_a).$ Hint: neglecting kinetic and potential

energy, the first law reduces to $W=H$ for

b$)$ If the turbine were reversible in addition to being adiabatic $($i$.$e$.,$ isentropic$),$ what would be the

delivered work $(W_{isen}),$ and hence what is the turbine efficiency $()?$ Hint: find first the exit

temperature $(T_2)$ that would be obtained if the turbine were isentropic$?$