Final answer:
Temperature does not appear in the formula for calculating the heat required to melt a substance because this energy is used to break intermolecular forces rather than increase the substance's temperature during a phase change.
Step-by-step explanation:
The reason temperature does not appear in the formula to calculate the heat (q) required to melt a given mass (m) of a substance from a solid to a liquid state is that during a phase change, the energy added to the substance is used to break the intermolecular forces that hold the molecules in a fixed position within the solid, rather than increasing the kinetic energy of the molecules, which would increase the temperature. The formula for heat required during a phase change is q = m × ΔH, where ΔH is the enthalpy change associated with the phase change (either fusion or vaporization), and does not involve a temperature change (ΔT).
Detailed exploration of heat transfer during phase changes illustrates that the process involves redistributing energy at the molecular level without changing the motion of the molecules that determine the temperature of the substance. When heat is added, it allows for the phase transition by overcoming attractive forces to change the substance from solid to liquid (melting) or liquid to gas (boiling). Conversely, when heat is removed, it allows molecules to recombine, going from gas to liquid (condensation) or liquid to solid (freezing).