What does specific latent heat of vaporisation measure?

The specific latent heat of vaporisation specifically measures the energy required to convert 1 kilogram of a substance from liquid to gas without changing its temperature. This process occurs at the substance's boiling point and involves breaking the intermolecular forces that hold the molecules closely together in the liquid state.

This concept is important in understanding phase changes in materials, where energy is absorbed in the process of vaporisation. For example, when water is boiled, energy is added to it, allowing it to transition from a liquid to a gaseous state (steam) while maintaining a constant temperature during the phase change.

Understanding this principle is crucial for various applications in physics, engineering, and real-world scenarios such as cooking and weather phenomena. It also distinguishes latent heat of vaporisation from latent heat of fusion, which is the energy required to change a substance from solid to liquid at its melting point. This clarity helps in recognizing the specific physical transitions that various forms of energy facilitate.