Vaporizing

Vaporizing is the process by which a substance changes from a liquid or a solid into a gaseous state. In everyday use, vaporization often means the liquid-to-gas transition, but sublimation—solid to gas—also falls under the broad idea of vaporization. The transition requires energy input and depends on temperature and pressure.

Two common modes are evaporation and boiling. Evaporation occurs at the surface of a liquid and can happen at temperatures below the liquid’s boiling point; it is generally a slow, surface-driven process. Boiling occurs when the vapor pressure of the liquid equals the surrounding pressure, leading to the formation of vapor bubbles within the liquid and rapid phase change.

Vaporization is influenced by several factors. Temperature and ambient pressure are primary determinants: higher temperatures and lower pressures increase the rate of vaporization. The rate also depends on heat transfer to the liquid, surface area, turbulence, and the presence of dissolved substances or impurities, which can alter vapor pressure.

Vaporization has widespread applications. Distillation uses controlled vaporization and subsequent condensation to separate components. Drying and evaporative concentration remove water or other solvents from solutions. In nature, evaporation is a key part of the water cycle, moving moisture from bodies of water into the atmosphere. Substances with appreciable vapor pressures at room temperature can form vapors that contribute to atmospheric phenomena or hazard if inhaled or ignited; safety measures in industrial contexts address vapors’ flammability and toxicity.

Terminology notes: a vapor is the gaseous phase of a substance that is usually liquid or solid at room temperature; a gas is a state with no distinct phase boundary at given conditions.