Reactant A can participate in both of these reactions:1) A + B  C + D   Grxn = –15.6 kJ2) A + E  F + G    Grxn = –20.5 kJReaction 1 has a much higher rate than Reaction 2 under the same reaction conditions. Explain this observation in terms of activation energy.

The activation energy is the amount of energy required to initiate a certain reaction. The activation energy may considered as an "energy barrier" that has to be overcome in order for a reaction to begin. If a reaction has a lower activation energy, then it will occur more easily and at a faster rate than a reaction with a higher activation energy. Therefore, the reason that reaction 1 is faster than reaction 2 is because it has a lower activation energy than reaction 2.