Final answer:
In chemical reactions, potential energy changes as bonds break and form, absorbing energy when bonds break and releasing it when new bonds form.
Step-by-step explanation:
The form of energy that changes in chemical reactions due to bonds breaking and forming is potential energy. During these reactions, chemical bonds - which hold the atoms together in a molecule - are broken and new ones are formed. Chemical potential energy is the energy due to the electrical forces between electrons and nuclei in these bonds. Breaking chemical bonds absorbs energy, while forming new bonds releases energy. The amount of energy involved in these processes is measured in joules (or kilojoules).