François Marie Raoult

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François Marie Raoult

François Marie Raoult (born May 10, 1830 in Fournes-en-Weppes , Département Nord , † April 1, 1901 in Grenoble ) was a French physicist and chemist .


After a stay at the high school in Reims in 1853 and various intermediate stations, he became professor of chemistry in Sens lycee in 1862, where he wrote a thesis on electromotive force, for which he received his doctorate in Paris the following year . In 1867 he was responsible for teaching chemistry in Grenoble and three years later he was given the chair of chemistry , which he held until his death on April 1, 1901. Raoult's earliest research dealt with physical issues, especially with the appearance of the galvanic cell. Later he devoted himself to more purely chemical questions.

His name is best known for working on solutions, to which he devoted the last two decades of his life. His first work dealt with the lowering of the freezing point of liquids by the presence of other substances. Further studies and experiments with different solvents besides water like benzene and acetic acid led him to a simple relationship between the molecular weight of the substances and the freezing point of the solvent and that if a molecule of a substance can be dissolved in a molecule of any solvent, the temperature of the freezing point of the latter was lowered by 0.63 ° C.

Another connection he worked on was the reduction of the vapor pressure of a solvent by dissolving a substance, which is proportional to the molar mass of the solute, at least when it dilutes the solution. These two generalizations not only provided a new method for determining the molar mass of substances, but were also used by Jacobus Henricus van 't Hoff , Wilhelm Ostwald, and other chemists to support the hypothesis of electrolytic dissociation in solution. Raoult's law , named after him, describes the vapor pressure of ideal mixtures.



  • Morachevskii, AG: Francois Marie Raoult (To 175th Anniversary of His Birthday) . In: Russian Journal of Applied Chemistry . 78, No. 5, 2005, pp. 856-858. doi : 10.1007 / s11167-005-0409-6 .
  • Wisniak, Jaime: François-Marie Raoult: Past and Modern Look . In: The Chemical Educator . 6, No. 1, 2001, pp. 41-49. doi : 10.1007 / s00897000432a .
  • Getman, Frederick H .: Francois-Marie Raoult, Master Cryoscopist . In: Journal of Chemical Education . 13, 1936, pp. 153-155. doi : 10.1021 / ed013p153 .
  • Raoult, François Marie . In: Encyclopædia Britannica . 11th edition. tape 22 : Poll - Reeves . London 1911, p. 898 (English, full text [ Wikisource ]).

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