What is internal energy change when $62 \mathrm{~J}$ of work is done on the system and $128 \mathrm{~J}$ of…
What is internal energy change when $62 \mathrm{~J}$ of work is done on the system and $128 \mathrm{~J}$ of heat is transferred to surrounding?
-62 J
-190 J
-128 J
-66 J
Solution
Work done on the system $=+62 \mathrm{~J}$
Heat released to the surrounding $=-128 \mathrm{~J}$
From first law of thermodynamics,
$\begin{aligned}
& \Delta \mathrm{U}=\mathrm{q}+\mathrm{W} \\
& =-128+62 \\
& =-66 \mathrm{~J}
\end{aligned}$