5.1 enthalpy change

Enthalpy of reaction

The enthalpy change when the amounts of reactants shown in the stoichiometric equation react to form the products, with all species in their standard states

Can be exothermic or endothermic

Enthalpy of formation

The enthalpy change when one mole of a compound is formed from its elements in their standard states

• Can be both exothermic and endothermic

Enthalpy of combustion

• The enthalpy change when one mole of a substance, in its standard state, is burnt in excess oxygen

• It is an exothermic change

Enthalpy of neutralisation

• The enthalpy change when one mole of water is formed by reacting an acid and an alkali

• It is an exothermic change

Ionisation enthalpy

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

Electron affinity

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

Enthalpy of atomisation

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

Hydration enthalpy

Enthalpy change when one mole of gaseous ions dissolves in sufficient water to form an infinite dilution

Enthalpy change of solution

Enthalpy change when one mole of an ionic solid dissolved in enough water to form a very dilute solution under standard conditions

Lattice enthalpy of formation

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

Lattice enthalpy of dissociation

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

Enthalpy of vaporisation

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