Question

A closed system contains $10kg$ of saturated liquid ammonia at ${10}^{o}C$. Heat addition required to convert the entire liqid into saturated vapour at a constnat pressure is $16.2MJ$. If the entropy of the saturated liquid is $o.88kJ/kgK$, the entropy (in $kJ/kgK$) of saturated vapour is

• A. 6.604

Answer 1

The correct option is A 6.604
Given, $m=10kg,T={10}^{o}C$
For closed system, $\delta Q=TdS$



$\therefore \delta Q=mT(s_g-s_f)$
$\therefore s_g=\frac{\delta Q}{mT}+s_f=\frac{16.2\times {10}^3}{10\times (273+10)}+0.88$
$=5.724+0.88$
$=6.604kJ/kgK$