OCR AS CHEMISTRY UNIT 2, Enthalpy Key Terms

the heat energy transfered in a reaction at constant pressure (in KJmol-1)

the enthalpy change when amounts of reactants as shown in the reaction equation react together under standard conditions to give the products in their standard states.

the enthalpy change when one mole of a compound is formed from it's elements under standard conditions: the comound and the elements muct be in their standard states.

the enthalpy change when one mole of a substance in completely combusted under standard conditions. 

the average engery needed (+) to break one mole of a bond type in a gaseous state.

the total enthalpy change of a chemical reaction is independent of the route by which the reaction takes place, provided the initial and final conditions are the same.