Question

At ordinary temperatures, the molecules of a diatomic gas have only translational and rotational kinetic energies. At high temperatures, they may also have vibrational energy. As a result of this compared to lower temperatures, a diatomic gas at higher temperatures will have-

• A. lower molar heat capacity
• B. higher molar heat capacity
• C. lower isothermal compressibility
• D. higher isothermal compressibility

Answer 1

The correct option is B higher molar heat capacity

Vibrational energy involves additional degrees of freedom. Thus the degrees of freedom for a diatomic gas increases at higher temperatures.

Molar heat capacity is proportional to the number of degrees of freedom of the gas.

Thus the molar heat capacity also increases for a diatomic gas at higher temperatures.