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This is illustrated in the vapor pressure chart (see right) that shows graphs of the vapor pressures versus temperatures for a variety of liquids. [7] At the normal boiling point of a liquid, the vapor pressure is equal to the standard atmospheric pressure defined as 1 atmosphere, [1] 760 Torr, 101.325 kPa, or 14.69595 psi.
Raoult's law (/ ˈ r ɑː uː l z / law) is a relation of physical chemistry, with implications in thermodynamics.Proposed by French chemist François-Marie Raoult in 1887, [1] [2] it states that the partial pressure of each component of an ideal mixture of liquids is equal to the vapor pressure of the pure component (liquid or solid) multiplied by its mole fraction in the mixture.
The vapor pressure of water is the pressure exerted by molecules of water vapor in gaseous form (whether pure or in a mixture with other gases such as air). The saturation vapor pressure is the pressure at which water vapor is in thermodynamic equilibrium with its condensed state .
Isotherms of an ideal gas for different temperatures. The curved lines are rectangular hyperbolae of the form y = a/x. They represent the relationship between pressure (on the vertical axis) and volume (on the horizontal axis) for an ideal gas at different temperatures: lines that are farther away from the origin (that is, lines that are nearer to the top right-hand corner of the diagram ...
David R. Lide (ed), CRC Handbook of Chemistry and Physics, 84th Edition.CRC Press. Boca Raton, Florida, 2003; Section 6, Fluid Properties; Vapor Pressure Uncertainties of several degrees should generally be assumed.
where p* is the vapor pressure of the pure component. At first sight, Raoult's law appears to be a special case of Henry's law, where H v px = p *. This is true for pairs of closely related substances, such as benzene and toluene , which obey Raoult's law over the entire composition range: such mixtures are called ideal mixtures.
The definition of a w is where p is the partial water vapor pressure in equilibrium with the solution, and p* is the (partial) vapor pressure of pure water at the same temperature. An alternate definition can be a w ≡ l w x w {\displaystyle a_{w}\equiv l_{w}x_{w}} where l w is the activity coefficient of water and x w is the mole fraction of ...
Vapor pressure is a measurement of how readily a condensed phase forms a vapor at a given temperature. A substance enclosed in a sealed vessel initially at vacuum (no air inside) will quickly fill any empty space with vapor. After the system reaches equilibrium and the rate of evaporation matches the rate of condensation, the vapor pressure can ...