Enthalpy defentions 3.1.8

Enthalpy of formation ΔH⦵f

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

Enthalpy of combustion ΔH⦵c

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

E.g. H2 + ½ O2 → H2O

Ionisation enthalpy ΔH^⦵i

Enthalpy change when one mole of gaseous atoms loses one electron per atom to produce one mole of 1+ ions

E.g. Mg(g) → Mg+(g) + e-

Electron affinity ΔH^⦵ea

Enthalpy change when one mole of gaseous atoms gains one electron per atom to produce one mole of 1- ions

E.g. O(g) + e- → O-(g)

Enthalpy of atomisation ΔH^⦵a

Enthalpy change when one mole of gaseous atoms is produced from an element in its normal state

E.g. ½ I2(s) → I-(g)

Hydration enthalpy ΔH^⦵_hyd

Enthalpy change when one mole of gaseous atoms become hydrated (dissolved in water)

E.g. Mg2(g)+ +aq → Mg2+(aq)

Enthalpy of solution ΔH⦵sol

Enthalpy change when one mole of ionic solid dissolves in an amount of water large enough so that the dissolved are well separated and do not interact with each other

E.g. MgCl2(s) + aq → Mg2+ (aq) + 2Cl-(aq)

Bond dissociation enthalpy ΔH⦵dis

Enthalpy change when one mole of covalent bonds is broken in the gaseous state

E.g. I2(g) → 2I(g)

Lattice enthalpy of formation ΔH^⦵L

Enthalpy change when one mole of solid ionic compound is formed from its constituent ions in the gas phase

E.g. Mg2+(g) + 2Cl-(g) → MgCl2(s)

Lattice enthalpy of dissociation ΔH^⦵L

Enthalpy change when one mole of solid ionic compound is broken up into its constituent ions in the gas phase

E.g. MgCl2(s) → Mg2+(g) + 2Cl-(g)

Enthalpy of vaporisation ΔH^⦵vap

Enthalpy change when one mole of atoms is converted to the gaseous state

E.g. Mg(s) → Mg(g)