Question

The temperature of 5 moles of a gas is changed from ${100}^{\circ }C$ to ${120}^{\circ }C$ at a constant volume. The change in internal energy is 80 J. Find the heat capacity of the gas at constant volume.

Answer 1

Here, $n=5moles$
$\Delta T=120-100={20}^{\circ }C$
$\Delta U=80J$
We know that, $\Delta U=n{C}_v\Delta T$
$\Rightarrow 80=5\times C_v\times 20$
$\Rightarrow C_v=\frac{4}{5}J/molK$