Fázisváltoztatás

Fázisváltoztatás, in physics and chemistry, refers to the transition of a substance from one state of matter to another. These transitions are driven by changes in temperature and pressure. The most common phase changes include melting (solid to liquid), freezing (liquid to solid), vaporization or boiling (liquid to gas), condensation (gas to liquid), sublimation (solid to gas), and deposition (gas to solid).

During a phase change, the substance absorbs or releases energy, known as latent heat, without a change in temperature. For example, when ice melts into water at 0 degrees Celsius, it absorbs latent heat of fusion. Similarly, when water boils into steam at 100 degrees Celsius, it absorbs latent heat of vaporization. The reverse processes, freezing and condensation, release equivalent amounts of latent heat.

The specific conditions under which a phase change occurs are defined by the substance's phase diagram, which plots pressure against temperature. Triple points represent the unique temperature and pressure where all three phases—solid, liquid, and gas—can coexist in equilibrium. Critical points mark the temperature and pressure above which a distinct liquid and gas phase no longer exist, and the substance exists as a supercritical fluid. Understanding phase changes is crucial in various scientific and engineering applications, from weather forecasting to material science.