vapor pressure


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vapor pressure

n.
1. The pressure exerted by a vapor in equilibrium with its solid or liquid phase. At the vapor pressure, there is no net evaporation. Also called evaporation pressure.
2. The pressure exerted by water vapor in the atmosphere.

va′por pres`sure


n.
the pressure exerted by the molecules of a vapor.

vapor pressure

1. The pressure exerted by water vapor in the atmosphere.
2. The pressure exerted by a vapor on the solid or liquid phase with which it is in equilibrium. At pressures lower than the vapor pressure, atoms or molecules of the liquid or solid being vaporized can escape from the surface of the liquid or solid. At the vapor pressure, they cannot escape because the two phases are in equilibrium.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.vapor pressure - the pressure exerted by a vaporvapor pressure - the pressure exerted by a vapor; often understood to mean saturated vapor pressure (the vapor pressure of a vapor in contact with its liquid form)
force per unit area, pressure, pressure level - the force applied to a unit area of surface; measured in pascals (SI unit) or in dynes (cgs unit); "the compressed gas exerts an increased pressure"
References in periodicals archive ?
"Vapor pressure describes how a compound behaves when it transitions from a liquid to a gas," said Tara Lovestead, a NIST chemical engineer and the lead author of the study.
Nevertheless, it is important to note that increasing LSWT leads to higher vapor pressure gradients (Fig.
Secondly, the low boil point of methanol leads to high possibility of vapor lock by raising the vapor pressure of methanol-gasoline [12-17].
Representative bioblendstocks identified as meeting the screening criteria described above were blended into a gasoline blendstock or a gasoline surrogate and tested for vapor pressure (Reid Vapor Pressure [RVP] as DVPE [dry vapor pressure equivalent] by ASTM Method D5191), distillation curve (ASTM Method D86), oxidation stability (ASTM Method D525), as well as measurement of RON (D2699) and MON (D2700).
(12.) Anderson, V.F., Anderson, J.E., Wallington, T.J., Mueller, S.A., and Nielsen, O.J., "Vapor pressures of alcohol- gasoline blends", Energy and Fuels, 24:3647-3654, 2010.
The graphite in reaction zone (2), confined with silica melt at high temperature, has relatively high SiO vapor pressure; thus its conversion rate for coating formation would be rather fast when compared to the that of reaction zone (1).
The vapor pressure of methanol, ethanol and 2-butanol is significantly lower than the vapor pressure of the reference fuel.
However, the vapor pressure of R-404A exceeds those of R-407A and R-407F on average by 7 psi (48.3 kPa) at -20[degrees]F (-28.9[degrees]C) and nearly 12 psi (82.7 kPa) at 20[degrees]F (-6.7[degrees]C).
The collected low-volatile oil fraction used in vapor pressure measurement experiments constitutes about 60% by weight of the total oil of pyrolysis.
An absorbent article comprising a malodor control composition disposed therein, said malodor control composition comprising: at least one volatile aldehyde; an acid catalyst having a vapor pressure of about 0.01 to about 13 at 25[degrees]C.; and wherein said acid catalyst is 5-methyl thiophene carboxylic acid.
"Subcritical water" is water above 140[degrees]C and less than 374[degrees]Cata pressure of 0.36 MPa (i.e., saturated water vapor pressure at 140[degrees]C) or more.
Here E[T.sub.0] (mm [day.sup.-1]) is the reference ET; [R.sub.n] (MJ [m.sup.-2] [day.sup.-1]) is the net radiation at the crop surface; G (MJ [m.sup.-2] [day.sup.-1]) is soil heat flux density; [T.sub.a] ([degrees]C) is the mean daily air temperature at a height of 2 m; [e.sub.s] [u.sub.2] (m [s.sup.-1]) is the wind speed at a height of 2 m; [e.sub.s] (kPa) is saturation vapor pressure; [e.sub.a] (kPa) is actual vapor pressure; [e.sub.s] - [e.sub.a] (kPa) is vapor pressure deficit (VPD); [DELTA] (kPa [degrees][C.sup.-1]) is the slope of vapor pressure curve at the daily mean air temperature; and [gamma] (kPa [degrees][C.sup.-1]) is the psychrometric constant calculated as 0.665 x [10.sup.-3] P; in which P (kPa) is the atmospheric pressure.