An ebullioscope is an instrument for measuring the boiling point of a liquid. The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid This can be used for determining the alcoholic strength of a mixture, or for determining the molecular weight of a non-volatile solute based on the boiling-point elevation. Boiling-point elevation describes the phenomenon that the Boiling point of a Liquid (a Solvent) will be higher when another compound is added meaning that
The first ebullioscope was invented in 1838 by Brossard-Vidal, and was used for measuring alcoholic content. The advantage of this method was that the boiling point is relatively insensitive to other components such as sugars. Older alcoholimeters were based on measuring the density, which is more sensitive to the presence of other solutes. Alcoholometer is a special type of Hydrometer which is used for determining the Alcoholic strength of liquids [1][2]
A later version was built by the French chemist François-Marie Raoult, but the difficulty to determine the exact temperature was overcome by the invention of the Beckmann thermometer by Ernst Otto Beckmann in 1887. François-Marie Raoult ( May 10, 1830 - April 1, 1901) was a French chemist who conducted research into the behavior of solutions A Beckmann thermometer is a device used to measure small differences of temperature but not absolute temperature values Ernst Otto Beckmann ( July 4, 1853 &ndash July 13, 1923) was a German chemist who is remembered for his invention of the Beckmann differential This improvement made the ebullioscope a standard apparatus to determine the molecular weight of substances by its characteristic boiling-point elevation. The molecular mass (abbreviated m of a substance, more commonly referred to as molecular weight and abbreviated as MW, is the Mass of one
References
- ^ P. Doré. Leçons de chimie élémentaire appliquées aux arts industriels, 1857, 323-325.
- ^ William Crookes, The Chemical News and Journal of Physical Science, 1874, 30.
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