Question

The diagram shows the potential energy changes for a reaction pathway.

Answer 1

1) To find the change in enthalpy, determine the difference between the potential energy of the products and the potential energy of the reactants. (on this diagram, C-A) To find the activation energy, find the difference between the potential energy of the reactants and the "peak" of the curve (on this diagram, B-A). For this diagram, both the enthalpy and activation energy are positive.

2) If the reaction was exothermic, enthalpy would be negative, and the potential energy of the reactants would be greater than the potential energy of the products.