Enthalpy change definitions

Enthalpy of formation (delta fH)

Enthalpy change when one mole of a substance is formed from its constituent elements with all substances in their standard states

Enthalpy of combustion

Enthalpy change when one mole of a substance undergoes complete combustion in oxygen with all substances in their standard state

First ionisation Enthalpy

Enthalpy change when each atom in one mole of gaseous atoms loses one electron to form one mole of gaseous +1 ions

Second ionisation Enthalpy

Enthalpy change when each atom in one mole of gaseous +1 ions loses one electron to form one mole of gaseous +2 ions

First electron affinity

Enthalpy change when each atom in one mole of gaseous atoms gains one electron to form one mole of gaseous -1 ions

Second electron affinity

Enthalpy change when each atom in one mole of gaseous -1 ions gains one electron to form one mole of gaseous -2 ions

Enthalpy of atomisation

Enthalpy change when one mole if gaseous atoms is produced from an element in its standard state

Bond dissociation Enthalpy

Enthalpy change when one mole of covalent bonds is broken in the gaseous state, averaged over a range of compounds

Lattice Enthalpy

Enthalpy change when one mole of a solid ionic compound is broken apart into its constituent ions in the gaseous phase

Enthalpy of vaporisation

Enthalpy change when one mole of a liquid is turned into a gas