Question

1. if you start with a substance as a solid, what will happen to the molecules as you add thermal energy (heat)?

Explanation:

When heat is added to a solid substance, the thermal energy causes the molecules to gain kinetic energy. As a result, the molecules vibrate more vigorously around their fixed positions in the solid - state lattice. Eventually, if enough heat is added, the intermolecular forces are overcome and the solid may change state to a liquid (melting).

Answer:

The molecules will vibrate more vigorously. As more heat is added, the solid may eventually melt and the molecules will be able to move more freely.