vapeurs

Vapeurs, in the sense of vapors, refer to the gaseous phase that forms when a liquid or solid transitions to a gas. In physics and chemistry, vapors are typically associated with substances that are not normally gases at room temperature, such as liquids or solids that evaporate or sublime. The concept is closely linked to vapor pressure, which is the pressure exerted by a vapor in equilibrium with its condensed phase at a given temperature. Vapor pressure increases with temperature and is a measure of volatility.

Vapors form through processes such as evaporation, boiling, and sublimation. Evaporation occurs at the surface of a liquid below its boiling point, while boiling involves the rapid formation of vapor bubbles within the liquid. Sublimation describes a solid turning directly into a gas. Vapors can be humid, containing water vapor, or consist of volatile organic compounds and other substances released from materials or reactions. In atmospheric science, water vapor is a key component of humidity and participates in cloud formation through condensation when air cools to the dew point.

Common examples include water vapor, ethanol vapor, and acetone vapor. More specialized vapors arise in industrial contexts as process gases or solvents, which may be flammable or toxic and require appropriate containment and monitoring. Detection and characterization of vapors rely on techniques such as infrared spectroscopy, gas chromatography, and various sensors that measure concentration, humidity, and volatile content.

In everyday language, vapeurs can describe steam from cooking or moist air. In popular culture, the term is sometimes associated with vaping devices, whose exhaled product is an aerosol—tiny liquid droplets—rather than a pure vapor gas.