Melting is the change in which energy is transferred from the surroundings to the substance.

Explanation:
- When a substance undergoes melting, it changes from a solid state to a liquid state.
- During this process, energy is required to break the intermolecular forces holding the particles together in the solid state.
- The energy is absorbed from the surroundings in order to provide the particles with enough energy to overcome these forces and transition into the liquid state.
- This energy is called the heat of fusion or the latent heat of fusion.
- The heat of fusion represents the amount of energy required to melt a specific amount of substance at its melting point.
- Once the substance has melted and reached its melting point, it can absorb additional heat energy from the surroundings without a further increase in temperature.
- This is because the energy is being used to break the intermolecular forces rather than increasing the kinetic energy of the particles.
- As a result, the temperature of the substance remains constant during the melting process until all the solid has been converted into liquid.
- The amount of energy absorbed during melting depends on the specific substance and its mass.
- Different substances have different heat of fusion values, which are typically given in units of J/g or J/mol.
- For example, water has a heat of fusion of 334 J/g, which means that 334 Joules of energy are required to melt 1 gram of ice at 0 degrees Celsius.
- In summary, melting is a process in which energy is transferred from the surroundings to the substance to break the intermolecular forces and convert the substance from a solid to a liquid state.