The diagram shows the potential energy changes for a reaction pathway. A curved lined graph is shown. The y axis of the graph has the title Potential Energy. The x axis of the graph has the title Reaction Pathway. The graph curve begins at a higher level and ends at a slightly lower level. A vertical line labeled A, starting from the x axis till the beginning of the graph line is shown. A vertical line labeled B, starting from the x axis till the uppermost hump in the graph curve is shown. Another vertical line labeled C is shown from starting from the x axis till the point where the graph curve ends. Part 1: Does the diagram illustrate an endothermic or an exothermic reaction? Give reasons in support of your answer. Part 2: Describe how you can determine the total change in enthalpy and activation energy from the diagram and if each is positive or negative.