Energetics

• Standard Enthalpy Change of a Reaction

  The enthalpy change which accompanies a reaction in the molar quantities shown in the balanced equation, under standard conditions.
• Enthalpy Change of Combustion

  Enthalpy change when one mole of a compound is completely burnt in oxygen, under standard conditions.
• Enthalpy of Neutralisation

  Enthalpy change when an acid reacts with an alkali to form one mol of water, under standard conditions.
• Enthalpy of Formation

  Enthalpy change when one mol of a compound is formed from its constituent elements in their standard states, under standard conditions.
• Lattice Enthalpy

  Enthalpy change when one mol of an ionic compound is formed from its constituent gaseous ions, under standard conditions.
• Enthalpy of Atomisation

  Enthalpy change when one mol of gaseous atoms are formed from its element in its standard state, under standard conditions.
• 1st Ionisation Energy

  Energy required to remove one mol of electrons from one mol of gaseous atoms to form one mol of gaseous 1+ ions.
• 2nd Ionisation Energy

  Energy required to remove one mol of electrons from one mol of gaseous 1+ ions to form one mol of gaseous 2+ ions.
• 1st Electron Affinity

  Energy released when one mol of gaseous atoms gains one mol of electrons to form one mol of gaseous 1- ions.
• 2nd Electron Affinity

  Energy required when one mol of gaseous 1- ions gains one mol of electrons to form one mol of gaseous 2- ions.
• Enthalpy of Solution

  Enthalpy change when one mol of a solute completely dissolves in H2O, under standard conditions.
• Enthalpy of Hydration

  Enthalpy change when one mol of gaseous ions dissolves in H2O to form one mol of aqueous ions.
• Bond enthalpy: the energy required to break a covalent bond in a molecule