Question

One mole of a diatomic ideal gas is cooled from 200oC to 50oC. Determine the change in the translational kinetic energy and the change in the internal energy of the gas

Answer 1

The change in the translational kinetic energy:

$$\Delta K=\frac{3}{2}nR(T_2-T_1)$$

$$\Delta K=\frac{3}{2}(1)(8.31)(50-200)=-1870\ J$$

The change in the internal energy of the gas:

$$\Delta U=\frac{5}{2}nR(T_2-T_1)$$

$$\Delta U=\frac{5}{2}(1)(8.31)(50-200)=-3120\ J$$