$3($a$)\_$#$1$: A piston$-$cylinder assembly undergoes a polytropic expansion from $120lb\frac{f}{i}{n}^2,2\mathrm{.}75$

$f\frac{t^3}{l}b$ to $20lb\frac{f}{i}{n}^2$ with $n=1\mathrm{.}32.$ Determine the amount of heat transfer, $Bt\frac{u}{l}b,$ which occurs

during the process for the following substances. Also, sketch each process on a $p-q$ diagram and

indicate the work.

a$)$ Water $(163\mathrm{.}77$ Btu$/$lb $($out$))$

b$)$ Ammonia $(80\mathrm{.}64$ Btu$/$lb $($out$))$