kJ/mol
kilojoule per mole
Molar energyexact by definition
The kilojoule per mole is the standard unit of chemical energy, exactly 1000 J/mol by decimal prefix. A covalent single bond runs 150 to 500 kJ/mol, a hydrogen bond about 20, and the combustion of methane releases 890 kJ/mol. It is the unit of every table of standard enthalpies of formation.
Watch out: Watch the sign convention. An exothermic reaction has a negative ΔH, because the system loses energy, even though the surroundings get hotter. A bond dissociation energy is positive because breaking a bond costs energy.
| 1 kJ/mol | 1 kJ/mol |
Solvers that use molar energy