Kilocalorie per mole

The kilocalorie per mole is a derived unit of energy per Avogadro’s number of particles. It is the quotient of a kilocalorie (1000 thermochemical gram calories) and a mole, mainly used in the United States.

In SI units, it is equal to 4.184 kJ/mol, or 6.9477×10⁻²¹ J per molecule. At room temperature (25 °C, 77 °F, or 298.15 K) it is equal to 1.688 $k_B T$ .

Physical quantities measured in kcal·mol⁻¹ are usually thermodynamical quantities; mostly free energies such as:

Heat of vaporization
Heat of fusion
Ionization energy