Reaction pathway diagrams display information about the energy changes during chemical reactions. Chemical energy Energy changes occur in chemical reactions as bonds are broken and new bonds formed.

the product of the reaction has a lower energy content than the donor molecule that preceded it in the pathway. At the same time, electron acceptor molecules capture some of the energy lost from ...

The reaction shown by the second diagram is more exothermic. There is a greater difference in energy between the reactants and products. The green arrow is longer.