Heat and Thermodynamics

4.5 Energy of Gas Molecules

We have proved that the temperature of a mass of gas is determined by the mean kinetic energy of the molecules. We now proceed to enquire about the nature of energy possessed by a molecule. In mechanics, we are familiar with the following types of energies:

1. The kinetic energy of translational motion: This is equal to 1/2 mc² where m is the mass of the molecule moving with velocity c.
2. The kinetic energy of rotation: This is equal to 1/2 Iw² where I is the moment of inertia of the molecule rotating with angular velocity w.
3. The vibrational energy: This is partly kinetic and partly potential. The average value of vibrational kinetic energy is equal to the average value of vibrational potential energy.
4. The energy of a ...