What happens to the particles in matter when hear energy is added to them

There are two possible situations.
1) If a phase change is not occurring, then the heat added contributes to increased translational energy of the particles. What that means is the particles move/vibrate faster.
2) If a phase change is occurring, then the heat added contributes to the breaking of bonds or intermolecular forces (depending on the chemical nature of the matter you're dealing with).

Answercreating graphs and performing calculations;

D. h2o + h2o > h3o + oh- confirmed.