This graph shows the energy involved in a reaction involving two molecules. Describe what is happening or what the state of the reaction is at A, B, C, and D. Then tell if this is an exothermic or an endothermic reaction.

If the graph shows that the energy increases as the reaction proceeds, this means that the state of the reaction of the compounds A, B, C and D is exothermic because the system releases heat to the surroundings, thus, resulting to the increase in energy involved in the reaction.