Internal energy (U) is defined so that changes in internal energy (U) are equal to the heat absorbed or released by a process running at constant volume. While changes in internal energy can be measur [..]

The energy of a system exclusive of its kinetic energy of mass motion and its potential energy arising from external forces. The internal energy of a system of molecules is the sum of their translatio [..]

Internal energy (U) is the total energy of a closed system. Internal energy is the sum of potential energy of the system and the system's kinetic energy. The change in internal energy (ΔU) of [..]

The sum of the potential energies of the molecular interactions and the kinetic energies of the molecular motions of all the particles of the system. The total energy of a thermodynamic system.

Total potential and kinetic energy of the molecules and atomic particles of a substance.

Sum of all the potential energy and all the kinetic energy of all the molecules of an object

The internal energy of a system is the sum of the energy of all the particles in the system, measured by reference to the centre of mass of the system. For a perfect gas (a good approximation for the [..]

the total of all possible kinds of energy present in a substance or substances.