what happens to a molecule

Question

describe what happens to the molecules of a substance when it is heated

Answer 1

Heat is a form of energy (thermal energy).

When molecules of a substance are heated, they increase their kinetic energy, and they move faster.  The thermal energy is transferred to the molecules.  As they move faster and become further and further apart from each other, they will eventually change phase, if enough heat is supplied.  A solid will become a liquid, and a liquid will become a vapor (gas).