What is the term for the temperature at which a substance changes from solid to liquid?

The temperature at which a substance transitions from a solid state to a liquid state is referred to as the melting point. This is the specific temperature at which the molecular structure of a solid breaks down sufficiently for it to flow as a liquid. At the melting point, the solid and liquid phases of a substance exist in equilibrium, allowing for the conversion between the two states.

In solid form, the particles are tightly packed in a structured arrangement. When the temperature rises to the melting point, the energy supplied to the substance increases the kinetic energy of the particles, eventually overcoming the forces that hold them together in the solid state. This transition is essential in various contexts, including understanding material properties, phase changes, and thermal dynamics.

Other terms provided in the choices refer to different processes. The freezing point is the temperature at which a liquid turns into a solid and is usually the same value as the melting point, but it describes the reverse process. The boiling point is the temperature at which a liquid turns into a gas, while the sublimation point relates to the direct transition from solid to gas without passing through the liquid phase. Thus, the choice of melting point accurately captures the process of solid to liquid transformation.