Enthalpies for Different Types of Reactions

Not every enthalpy change is a full reaction enthalpy — chemists also tabulate enthalpies for specific, standardised physical/chemical events so they can be combined via Hess's law:

• Standard Enthalpy of Combustion — burning one mole of a substance completely in oxygen.
• Enthalpy of Atomization — breaking one mole of a substance into free gaseous atoms.
• Bond Enthalpy — the energy to break one mole of a specific bond in the gas phase.
• Lattice Enthalpy — separating one mole of an ionic solid into its gaseous ions. …