Heat of fusion is associated with which physical process?

Heat of fusion refers to the amount of energy required to change a substance from a solid to a liquid at its melting point. This process involves breaking the bonds that hold the molecules in a solid form, allowing them to move freely and transition into a liquid state.

When a solid absorbs enough heat, it reaches a point where it begins to melt, and this is when the heat of fusion comes into play. The energy absorbed during this melting process does not raise the temperature of the substance but rather is used to overcome the intermolecular forces that hold the solid together.

This concept is central to understanding phase changes in matter, specifically focusing on the transition from solid to liquid, making it explicitly linked to melting. In contrast, the other options involve different processes: condensation relates to gas converting to liquid, sublimation is the transition from solid to gas, and vaporization involves liquid turning into gas.