Question

One mole of an ideal monoatomic gas is initially at $300K$. Find the final temperature (in $K$) if $200J$ of heat are added at constant pressure.

Answer 1

At constant pressure process,
Heat supplied $\delta q=n{C}_p\Delta T$

$C_p=\frac{\gamma R}{\gamma -1}$ $\gamma =\frac{5}{3}$

Hence
$C_p=\frac{5}{2}R$

$\Delta T=T_2-T_1=\frac{\delta q}{n{C}_p}=\frac{200\times 2}{5R}=10K$

i.e. final temperature $=T_2=T_1+10=310K$