Vapores

Vapors are the gaseous forms of substances that are liquids or solids at room temperature. They are produced by evaporation or sublimation and exist as a gas under certain conditions, making them distinct from substances that are gases by their nature. For example, water vapor is the gaseous form of water, while acetone vapor is the gas released from liquid acetone.

Key properties of vapors include vapor pressure, volatility, and their behavior during heating and cooling. Vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid or solid form; higher vapor pressures indicate a greater tendency to evaporate. Temperature and ambient pressure determine whether a substance is found as a vapor, liquid, or solid. Vapors diffuse and mix with air, and their concentration is influenced by enclosure, ventilation, and distance from the source.

Detection and measurement of vapors rely on specialized equipment and analytical methods. Common detection devices include photoionization detectors, electrochemical sensors, and infrared spectroscopy, while laboratories may use gas chromatography to identify and quantify individual vapor components. Concentrations are typically expressed in parts per million (ppm) or milligrams per cubic meter (mg/m3). Health and safety considerations depend on the substance: many vapors are toxic, irritating, flammable, or reactive. Proper ventilation, engineering controls, and personal protective equipment are used to manage exposure.

Applications and contexts for vapors span industry and environment. They are fundamental to distillation, solvent recovery, fragrance and flavor production, and aerosol technology. In the atmosphere, water vapor is a major component of weather and climate systems, while emissions of industrial vapors are subject to regulatory controls to protect air quality and worker safety.