Final answer:
On a heating curve, the Heat of Vaporization represents the phase change from a liquid to a gas, occurring at a constant temperature while the substance absorbs heat.
Step-by-step explanation:
The phase change that can occur on a heating curve during the Heat of Vaporization is the transition from a liquid to a gas. When a substance reaches its boiling point, the temperature remains constant as the heat energy is used to break the intermolecular forces and turn the liquid into vapor. This process is endothermic, meaning heat is absorbed during this phase change. The energy required for this transformation is known as the enthalpy of vaporization (∆Hvap).
On a typical heating curve for water, as the temperature rises, the substance passes through different stages such as heating of solid ice, melting at 0 °C, heating of liquid water, boiling at 100 °C (where vaporization occurs), and finally the heating of water vapor. The portion of the heating curve where the temperature remains flat while the phase change occurs represents the Heat of Vaporization.