What information does a reaction coordinate diagram typically convey?

A reaction coordinate diagram is a graphical representation that illustrates the energy changes that occur during a chemical reaction as reactants transition to products. This type of diagram typically features the reaction progress on the x-axis, which can be thought of as a map of the reaction pathway from reactants to products, and the potential energy on the y-axis.

As the reaction proceeds, the diagram shows how the energy of the system changes. This includes identifying energy barriers (activation energy), which are critical for understanding reaction rates and mechanisms. The diagram can highlight the energies of the reactants, the transition states (where the system has maximum energy), and the final products. Therefore, option C, which refers to the energy changes during a reaction, accurately captures the primary function of a reaction coordinate diagram.

In contrast, the other options focus on aspects that are not depicted in a reaction coordinate diagram. Temperature changes are not typically represented, nor are pH levels or specific products mentioned. While the concentration of products may influence the energy landscape, the types of products themselves are not directly illustrated in the diagram. Thus, understanding energy changes is central to analyzing chemical reactions, which is precisely what a reaction coordinate diagram conveys.