Enthalpy

•It is defined as the heat content of a system or total energy in the system.

•The unit for enthalpy is Joule (J).

•The total enthalpy, H, of a system cannot be measured directly.

•Thus, change in enthalpy, ΔH, is a more useful quantity than its absolute value.

•The change in enthalpy is also known as the heat of reaction.

                                 Heat of reaction = Enthalpy change, ΔH

•The difference between the enthalpy of the products and the enthalpy of the reactants of a particular reaction. 

                                          ΔH = ΣH products – ΣH reactants

•The technique used to measure the enthalpy of the reaction, ΔH is called calorimetry. 

•There are 2 types of reaction 

          • Endothermic reaction 

          • Exothermic reaction