$(5)$

$12\mathrm{.}38$ Moist air initially at $125C,4$ bar, and $50\%$ relative humidity is

contained in a $2\mathrm{.}5-m^3$ closed, rigid tank. The tank contents are cooled.

Determine the heat transfer, in kJ $,$ if the final temperature in the tank

is $($a$)110C,($b$)30C.$