Enthalpy changes definitions

enthalpy change of formation

△fH. Enthalpy change when 1 mole of a compound is formed from its elements in their standard states

enthalpy change of atomisation

△atH. Enthalpy change when 1 mole of gaseous atoms is formed from an element

first ionisation energy

energy needed to chane 1 mole of gaseous atoms into 1 mole of gaseous 1+ ions

second ionisation energy

the energy needed to change 1 mole of 1+ gaseous ions into 2+ gaseous ions

lattice enthalpy

△LEH. enethalpy change when 1 mole of a solid ionic compound is formed from its gaseous ionic ions

first electron affinity

energy needed to change 1 mole of gaseous atoms into 1 mole of gaseous 1- ions

second electron affinity

energy needed to change 1 mole of gaseous 1- ions into gaseous 2- ions

enthalpy chnage of hydration

△hydH. Enthalpy change when 1 mole of gaseous ions is dissolved in water. The stronger the more negative it is.

enthalpy change of solution

△solH. enthalpy change when 1 mole of solutes is dissovled in a solvent like water

average bond enthalpy

breaking one mole of bonds in gaseous molecules