What is the Ea for the exothermic reaction A)332.6 kJ B)-85.1 kJ C)251.0 kJ D) -251.0 kJ

Option C. 251 kJ

Explanation:

The activation energy (Ea) of a given reaction is the minimum energy that must be overcomed for reactant to proceed to product.

The activation energy (Ea) can be obtained from an energy profile diagram by simply calculating the difference between the energy of the activation complex (i.e the peak) and the energy of the reactant.

Thus, we can obtain the activation energy for the reaction above as follow:

Activation complex = 332.6 kJ

Energy of reactant = 81.6 kJ

Activation energy =?

Activation energy = Activation complex – Energy of reactant

Activation energy = 332.6 – 81.6

Activation energy = 251 kJ

Therefore, the activation energy of the reaction is 251 kJ