Energy Change(∆H)
Chemical reactions take place with changes in energy. This energy change is symbolised as DH, the HEAT OF REACTION. ∆H is the DIFFERENCE between the energy of the products and the energy of the reactants. In the diagram above, the reactants have a higher energy than the products, and DH will therefore be a negative number.
Use of a Catalyst
The above Figure shows a difference in experimental results which may arise as the result of the availability of a catalyzed route which gives a product other than the thermodynamically most stable product of the reaction.
Activation Energy(Ea)
The smaller the activation energy, the faster the reaction takes place. The higher the activation energy, the slower the reaction occurs. At the peak of the curve, the molecule which has gained the activation energy has been converted to an activated complex. It is not a reactant, or a product, it could be either one.
