Question

What is meant by internal energy?

Answer 1

• Internal energy (U) of a system is equal to the energy possessed by all its constituents namely atoms, ions and molecules.
• The energy of a molecule is equal to the sum of its translational energy (U_v), vibrational energy (U_b), rotational energy (U_e), bond energy (jh’ electronic energy and energy due to molecular interactions (U_i).
• U = U_t + U_v + U_r + U_b + U_e + U_i
• The total energy of all the molecules of the system is called internal energy.