Kiehumislämpö

Kiehumislämpö, also known as the heat of vaporization, is the amount of energy required to convert a substance from a liquid state to a gaseous state at a constant temperature and pressure. This energy is absorbed by the substance during the phase transition, overcoming the intermolecular forces that hold the liquid molecules together. Conversely, when a gas condenses into a liquid at the same temperature and pressure, an equal amount of energy, known as the condensation heat, is released.

The magnitude of the kiehumislämpö is dependent on the specific substance and its intermolecular forces. Substances with stronger intermolecular forces, such as hydrogen bonding, generally have higher kiehumislämpö values because more energy is needed to break these bonds. For example, water has a relatively high kiehumislämpö compared to many other common liquids.

The kiehumislämpö is typically expressed in units of energy per unit mass, such as joules per kilogram (J/kg) or kilojoules per mole (kJ/mol). This property is crucial in various scientific and industrial applications, including distillation, evaporation, and refrigeration systems, where controlling phase changes is essential. Understanding kiehumislämpö helps in designing and optimizing processes that involve heating or cooling and phase transitions.