If enough heat is supplied to convert a substance from a solid to a liquid, what force is overcome?

When a solid is heated and enough energy is supplied to convert it into a liquid, it is primarily the force of cohesion that is being overcome. Cohesion refers to the intermolecular forces that hold the molecules of the solid together. These forces must be broken for the molecules to move freely, which is characteristic of liquids.

As heat is added, the energy increases the vibrations of the molecules, allowing them to reach a point where they can transition from a rigid structure to a more fluid state. This transition is essential in phase changes, and when the cohesion forces are surpassed, the solid no longer maintains its shape and begins to flow as a liquid.

Understanding this concept is fundamental in thermodynamics and material science, as it illustrates how heat energy influences the state of matter by affecting intermolecular forces.