Question $2$

$()$

Air expands in a piston$-$cylinder system from a pressure of $2200$ kPa and a temperature of $520C,$ to a pressure of $120$ kPa $.$ Determine the change of specific entropy and the final temperature if:

$2\mathrm{.}1$ The process occurred isothermally,

$2\mathrm{.}2$ The process occurred polytropically $)=(1\mathrm{.}22,$

$2\mathrm{.}3$ Draw T$-$s$-$diagrams to illustrate the two processes.