Ethylene gas at $250C$ and $38$ bar expands isentropically in an expander to $1\mathrm{.}20$bar $.$ Determine;

The temperature of the expanded gas," $525K$

The work produced,"?

If the efficiency of the expander is $0\mathrm{.}75,$ what would be the temperature of the expanded gas? $"$

For ethylene: $T_c=282\mathrm{.}3K,P_s=50.$bar $,=0\mathrm{.}087$ and for simplicty, take $C_F=55\frac{J}{\text{M}\text{o}\text{l}\text{.}k}.$