Summary:
- Heat is energy that is transferred from one object or substance to another because of a difference in temperature between them.
- Heat always flows from an object at a higher temperature to an object a lower temperature (see Figure below) The flow of heat will continue until the two objects are at the same temperature.
- When chemical reactions occur, some chemical bonds are broken, while new chemical bonds form.
- As a result of the rearrangement of atoms, the total chemical potential energy of the system either increases or decreases.