the sum of the kinetic and potential energies of all particles in the system is called the
Internal energy From the standpoint of statistical mechanics, the internal energy is equal to the ensemble average of the sum of the microscopic kinetic and potential energies of the system.
Joule per mole 1 kJ·mol−1 is equal to 0.239 kcal·mol−1 or 1.04×10−2 eV per particle. At room temperature (25 °C, 77 °F, or 298.15 K) 1 kJ·mol−1 is equal to 0.4034    k B  T  {\displaystyle k_{B}T} .