Studied by 0 people
Enthalpy of formation (ΔfH°)
Enthalpy change when one mole of a substance is formed from its constituent elements with all substances in their standard states.
Exothermic (-ve) for most substances.
Enthalpy of combustion (ΔcH°)
Enthalpy change when one mole of a substance undergoes complete combustion in oxygen with all substances in standard states.
Exothermic (-ve).
Enthalpy of neutralisation (ΔneutH°)
Enthalpy change when 1 mole of water is formed in a reaction between an acid and alkali under standard conditions.
Exothermic (-ve).
Ionisation enthalpy (ΔiH°) First ionisation energy
Enthalpy change when each atom in one mole of gaseous atoms loses one electron to form one mole of gaseous 1+ ions.
Endothermic (+ve).
Ionisation enthalpy (ΔiH°) Second ionisation energy
Enthalpy change when each ion in one mole of gaseous 1+ ions loses one electron to form one mole of gaseous 2+ ions.
Endothermic (+ve).
Electron affinity (ΔeaH°) 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.
Exothermic (-ve) for many non-metals.
Electron affinity (ΔeaH°) Second electron affinity
Enthalpy change when each ion in one mole of gaseous 1− ions gains one electron to form one mole of gaseous 2− ions.
Endothermic (+ve) (as adding -ve electron to -ve ion).
Enthalpy of atomisation (ΔatH°)
Enthalpy change when one mole of gaseous atoms is produced from an element in its standard state. Endothermic (+ve).
Hydration enthalpy (ΔhydH°)
Enthalpy change when one mole of gaseous ions becomes hydrated (dissolved in water). Exothermic (-ve).
Enthalpy of solution (ΔsolH°)
Enthalpy change when one mole of an ionic solid dissolves in an amount of water large enough so that the dissolved ions are well separated and do not interact with each other. Varies.
Bond dissociation enthalpy (ΔdissH°)
Enthalpy change when one mole of covalent bonds is broken in the gaseous state. Endothermic (+ve).
Lattice enthalpy of formation (ΔLEF°)
Enthalpy change when one mole of a solid ionic compound is formed from its constituent ions in the gas phase. Exothermic (-ve).
Lattice enthalpy of dissociation (ΔLEDH°)
Enthalpy change when one mole of a solid ionic compound is broken up into its constituent ions in the gas phase. Endothermic (+ve).
Enthalpy of vaporisation (ΔvapH°)
Enthalpy change when one mole of a liquid is turned into a gas. Endothermic (+ve).
Enthalpy of fusion (ΔfusH°)
Enthalpy change when one mole of a solid is turned into a liquid.
Endothermic (+ve).
