Chemistry: Enthalpy Definitions Yr2

Δ_fH – Enthalpy change of formation

The enthalpy change when 1 mole of a compound is formed from it’s elements in their standard states under standard conditions.

Δ_latticeH – Lattice enthalpy of formation

The enthalpy change when 1 mole of a solid ionic compound is formed from it’s gaseous ions under standard conditions.

Δ_latticeH – Lattice enthalpy of dissociation

The enthalpy change when 1 mole of a solid ionic compound is dissociated into it’s gaseous ions under standard conditions.

Δ_atH – Enthalpy change of atomisation

The enthalpy change when 1 mole of gaseous atoms is made from an element in it’s standard state.

Δ_dissH – Enthalpy change of dissociation

The enthalpy change when 1 mole of bonds of the same type of molecule in the gaseous state is broken.

Δ_ie1H – Enthalpy change of 1^st ionisation

The enthalpy change when 1 mole of gaseous 1+ ions are made from 1 mole of gaseous atoms.

Δ_ea1H – 1^st electron affinity

The enthalpy change when 1 mole of gaseous 1- ions are made from 1 mole of gaseous atoms.

Δ_ea2H – 2^nd electron affinity

The enthalpy change when 1 mole of gaseous 2- ions are made from 1 mole of gaseous 1- ions.

Δ_ie2H – Enthalpy change of 2^nd ionisation

The enthalpy change when 1 mole of gaseous 2+ ions are made from 1 mole of gaseous 1+ ions.

Enthalpy Change of Solution

The enthalpy change when 1 mole of an ionic substance is dissolved in the minimum amount of solvent to ensure no further enthalpy change is observed upon further dilution.

Enthalpy of Hydration

The enthalpy change when 1 mole of aqueous ions is formed from 1 mole of gaseous ions.