Fázisátalakulások

Fázisátalakulások refers to phase transitions, which are physical processes where a substance changes from one state (phase) to another. These transitions occur at specific temperatures and pressures. Common examples include melting, where a solid becomes a liquid, and boiling, where a liquid becomes a gas. Other transitions include freezing (liquid to solid), condensation (gas to liquid), sublimation (solid directly to gas), and deposition (gas directly to solid).

The driving force behind phase transitions is the change in the internal energy and entropy of the substance. At different temperatures and pressures, one phase becomes more thermodynamically stable than another. For instance, ice melts into water at 0 degrees Celsius at standard atmospheric pressure because, at this temperature, the liquid phase of water has a lower free energy than the solid phase.

Phase transitions can be classified into different types, such as first-order and second-order transitions. First-order transitions involve a discontinuous change in properties like enthalpy and entropy, meaning there's a latent heat associated with the transition. Boiling and melting are examples of first-order transitions. Second-order transitions, on the other hand, exhibit continuous changes in these properties, with no latent heat. Examples include the ferromagnetic to paramagnetic transition in certain materials. The study of fázisátalakulások is crucial in thermodynamics and statistical mechanics, with applications ranging from materials science to meteorology.