Enthalpy changes

• Enthalpy change definition

  Heat energy transferred in a reaction at a constant pressure
• Standard enthalpy of combustion

  Enthalpy Change when one mole is completely burned in oxygen under standard conditions
• Standard enthalpy of formation

  Enthalpy change when one mole of a compound is formed from its elements in their standard states under standard conditions
• Enthalpy Change of atomisation of a compound

  Enthalpy change when 1 mole of a compound in its standard state is converted to gaseous atoms
• Enthalpy change of atomisation of an element

  Enthalpy change when 1 mole of an element in its standard state is converted to gaseous atoms
• First ionisation energy

  Enthalpy change when 1 mole of gaseous 1+ ions is formed from 1 mole of gaseous atoms
• Second ionisation energy

  Enthalpy change when 1 mole of gaseous 2+ ions is formed from 1 mole of gaseous 1+ ions
• First electron affinity

  Enthalpy change when 1 mole of 1- gaseous ions is formed from 1 mole of gaseous atoms
• Second electron affinity

  enthalpy change when 1 mole of gaseous 2- ions is formed from 1 mole of gaseous 1- ions
• Enthalpy of hydration

  Enthalpy change when 1 mole of aqueous ions is formed from 1 mole of gaseous ions
• Bond dissociation enthalpy

  enthalpy change when 1 mole of a covalent bond is broken under standard conditions in the gaseous state
• Enthalpy of solution

  Enthalpy change when 1 mole of solute is dissolved in enough solvent that no further enthalpy change occurs on further dilution
• Lattice enthalpy of formation

  Enthalpy change when 1 mole of a solid ionic compound is formed from gaseous ions under standard conditions
• Lattice enthalpy of dissociation

  Enthalpy change when 1 mole of a solid ionic compound is separated into its gaseous ions under standard conditions