Vapor 32505 220128925 2008-06-18T12:20:02Z 62.176.111.68 added BG link {{otheruses4|the chemical use|computer usage|Vaporware}} {{Unreferenced|date=July 2007}} [[Image:watervapor cup.jpg|thumb|right|Water condenses into visible droplets after evaporating from a cup of hot tea]] '''Vapor''' or '''vapour''' (see [[spelling differences]]) is the [[gas phase]] component of another state of matter (e.g. liquid or solid) which does not completely fill its container. It is distinguished from the pure [[gas phase]] by the presence of the same substance in another state of matter. Hence when a liquid has completely evaporated, it is said that the system has been completely transformed to the gas phase. == Properties == ''Vapor'' refers to a gas phase in a state of [[thermodynamic equilibrium|equilibrium]] with identical matter in a [[liquid]] or [[solid]] state below its [[boiling point]]. The term ''gas'' refers to a compressible fluid phase. Fixed gases are gases for which no liquid or solid can form at the temperature of the gas (such as air at typical ambient temperatures). A liquid or solid does not have to boil to release a vapor. The [[atmospheric boiling point]] of a liquid is the [[temperature]] at which the [[vapor pressure]] is equal to one [[atmosphere (unit)]]. <br />''See the article on [[vapor pressure]] for more information on this topic.'' [[Image:Binary Boiling Point Diagram.PNG|left|thumb|Liquid-Vapor Equilibrium]] Vapor is responsible for the familiar processes of [[cloud]] formation and [[condensation]]. It is commonly employed to carry out the physical processes of [[distillation]] and [[headspace extraction]] from a liquid sample prior to [[gas chromatography]]. The [[vapor pressure]] is the equilibrium pressure from a liquid or a solid at a specific temperature. The equilibrium vapor pressure of a liquid or solid is not affected by the amount of contact with the liquid or solid interface. The [[physical chemistry]] behind [[distillation]] is based on manipulating the [[Vapor-liquid equilibrium|equilibrium]] occurring between the liquid and vapor phases of a molecule in [[solution]]. For two-phase systems (e.g., two liquid phases), the vapor pressure of the system is the sum of the vapor pressures of the two liquids. In the absence of stronger inter-species attractions between like-like or like-unlike molecules, the vapor pressure follows [[Raoult's Law]], or the vapor pressure is equal to the sum of the product of the vapor pressure of the pure compound and its mole fraction in the mixture for all of the constituents. The constituent [[atom]]s or [[molecule]]s of a vapor possess vibrational, rotational, and translational motion. More information can be found under the entry of the [[Kinetic theory of gases]]. <br style="clear:both" /> == Examples == [[Image:Crepuscular Rays Beam through the Mist Blown from Takkakaw Falls.jpg|thumb|Water vapor is responsible for humidity]] *[[Perfume]]s contain chemicals that vaporize at different temperatures and at different rate in scent accords known as [[note (perfumery) | note]]s. *[[Fog]], [[mist]] and [[haar (fog)|haar]] are meteorological designations for visible near surface [[water]] vapor. ==Measuring vapor== Since it is in the gas phase, the amount of vapor present is quantified by the [[partial pressure]] of the gas. Also, vapors obey the [[barometric formula]] in a gravitational field just as conventional atmospheric gases do. == Vapors of flammable liquids == [[Flammable liquid]]s do not burn when ignited. It is the vapor cloud above the liquid that will burn if the vapor's concentration is between the lower [[explosive limit]] and upper explosive limit of the flammable liquid. ==See also== {{Wiktionarypar2|vapour|vapor}} *[[Evaporation]] *[[Water vapor]] *[[Dilution (equation)]] *[[Vapor pressure]] *[[Vapor Trail]] *[[Vaporizer]] *[[Gas phase]] *[[Henry's Law]] *[[Raoult's Law]] {{State of matter}} [[Category:Gases]] [[Category:Pressure]] [[Category:Chemical properties]] [[bg:Пара]] [[de:Dampf]] [[el:Ατμός]] [[es:Vapor]] [[hr:Para]] [[it:Vapore]] [[he:אד]] [[nl:Damp]] [[ja:蒸気]] [[uz:Bugʻ]] [[pt:Vapor]] [[simple:Vapor]] [[sl:para]] [[fi:Höyry]] [[sv:Ånga]] [[zh:蒸氣]]