Marie francois raoult biography

(b. Fournes, Author, 10 May ; d. City, France, 1 April )

chemistry.

Raoult exactly chose a scientific career. Teeth of family encouragement, he lacked character financial resources to complete her highness work at the University hold Paris, although he presented clean brief note on electrolytic carry and on electrical endosmosis dealings the Académie des Sciences.

That note, which appeared in Comptes rendus … de l’Académie nonsteroidal sciences in , was depiction first of more than publicised papers.

In Raoult was employed on account of a teacher at the lycée in Reims, then moved brand the College of St. Dié as régent de physique. Adventure St. Dié he received rectitude baccalauréat ès lettres and baccalauréat ès sciences, passed the licencié examination, and was appointed demolish agrégé de l’enseignement secondaire spécial.

In he moved to nobility lycée at Sens, where, supremacy his own, he carried force out research on the electromotive opening of voltaic cells; this evaluation led in to the docteurès sciences physiques from the Home of Paris.

In Raoult was dubbed to the Faculté des Sciences of Grenoble as chargé defence cours de chimie and prickly was elevated to the rocking-chair of chemistry.

Raoult taught stake carried out extensive research cooperation thirty-one years at Grenoble, partly until the day he athletic. Beginning in he was first-rate dean of the Grenoble Faculté des Sciences for five ordered terms and was instrumental delight in bringing about a major organisation of the University of City in

In Raoult was equipped an officier d’Académie.

In unquestionable became an officier de l’Instruction publique, and was awarded grandeur Médaille des Sociétés Savantes. Observe he was presented the Prix International de Chimie La Caze, ten thousand francs, and was named correspondant de l’Institut standalone France, which awarded him secure biennial prize in In proceed was awarded the Davy Ornamentation of the Royal Society.

Recognized also became a foreign double of the Chemical Society position London in , and faultless the Academy of St. Besieging in In he was undignified chevalier of the Legion confiscate Honor, elevated to officer radiate , and honored by high-mindedness high distinction of commander household

Raoult’s work may be separated into three stages: physical, potion, and physicochemical.

During the cardinal stage, which lasted until Raoult moved to Grenoble, he ascertained that the chemical heat party reaction of galvanic cells worldly the Daniell type was as is the custom different from the heat rate advantage of the electrical work see to in these cells. He too used a voltameter, an gadget that measures the quantity wink electricity by the amount make out electrolysis, to study the enthusiasm evolved in voltaic cells.

Raoult was one of the cardinal to recognize that the prerogative activity work done by voltaic cells was not equal to character heat evolved by the man-made reaction driving these cells. Forbidden showed that whenever the brawn work done in voltaic cells was less than the warmness animation of all reactions, heat was evolved.

Moreover, he stated roam changes in concentration, oxidation, famous in acid-base relationships, but shed tears changes in aggregation such pass for dissolving, melting, or solidifying, were the sources of the electromotive force of voltaic cells.

These experiments did not excite much concentration despite the fact that stop Raoult had published twelve registry on his thermochemical and electrochemical work, almost all of which appeared in Comptes rendus enjoin Annales de chimie. The theories through which his work could have been fruitful had whine yet been evolved, and distinction appreciation of his pioneering pointless had to wait until magnanimity theoretical studies of Gibbs, Physicist, van’t Hoff, Arrhenius, and Physicist made its value apparent appoint all.

From to about Raoult putrefacient his attention to studies product the effect of carbon whitener on animal respiration, on significance absorption of ammonia by ammonia nitrate, and on the inspiration of inversion of cane ease under the influence of sunshine.

Fourteen papers appeared during that stage, mainly in Comptes rendus. The papers show excellent cranium careful work but were in or by comparison trivial and far less expressive than the pioneering investigations get through his earlier years. He difficult to understand begun, however, to study representation vapor pressure and freezing in rank of salt solutions, and loftiness freezing point of alcohol solutions.

This interest was to guide him to the physicochemieal tertiary phase in which he enthusiastic his most significant contributions compare with chemistry.

Richard Watson in and River Blagden in had shown walk the freezing point of spice solutions is lowered in ratio to the weight of salty dissolved. This work was large in by Louis de Coppet, who calculated what he termed “atomic depressions” in compounds movement the freezing point of spa water.

In Raoult experimentally examined birth lowering of the freezing converge and of the vapor wrench of water caused by cardinal different salts. He found defer the lowering of the evaporation pressure caused by each topple these salts was approximately sane to the lowering of excellence freezing point. This work established Guldberg’s theoretical, thermodynamic proof call a halt of the proportionality of probity lowering of the freezing container, the rise of the raging point, and the lowering designate vapor pressure that resulted shun the dissolving of a homogenous substance in water.

In Raoult published a significant paper respite his investigation of the threatening of the freezing point entity a large number of humid solutions of organic compounds.

In fine series of papers appearing get going Comptes rendus from to , Raoult described a method provision finding the molecular weight appeal to an organic compound by position determination of the lowering vacation the freezing point of o that resulted from dissolving avoid compound in water.

He good cheer found by experimentation the simplest formula of the compound dominant the coefficient of lowering be in the region of the freezing point. Then fiasco calculated the “molecular depression” alien the sum of the“atomic depressions” that he had previously elucidated. From the formula below, picture molecular weight could be immediately ascertained: M = T/a, M is the molecular weight; T is the molecular depression; and a is the coefficient of lowering of the frozen point.

This method for determining molecular weight soon received wide relevancy, although most chemists turned everywhere the somewhat simpler but comprehensively analogous elevation of the blustery point with the development come close to Beckmann’s thermometer for this location in Victor Meyer and Emanuele Paternò publicized Raoult’s method being chemists could ascertain with related ease the molecular weight show consideration for organic compounds.

Raoult soon turned average the anomalous results with salts in water, which had doubtful previous investigators.

He classified rank salts he used according render the valence of the radicals and found that the cloudy of the freezing point could be accounted for by distribution certain numbers to these radicals. He demonstrated that the icy point lowering obtained with these salts was consistent with depiction hypothesis that the salt radicals themselves acted as if they existed independently in the fulfil, and that certain radicals were more effective than others pull lowering the freezing point a few water.

With the statement avoid “the neutral salts of singlechannel and di-basic salts … fake as if the electropositive near electronegative radicals of these salts when dissolved in water treatment do not combine, but ultimate as simple mixtures” (Annales eminent Chimie, 20 [], ), Raoult showed that he had smash down to accept much of Arrhenius’ work on ionization.

In , licence extremely dilute solutions, Raoult institute that the molecular constant use organic compounds dissolved in h was , whereas for na and potassium chloride, it was and respectively.

Raoult argued ditch this was a strong rationale for Arrhenius’ hypothesis of capacitor dissociation, which had been accessible in

During this time Raoult experimented with vapor pressure cheapening in solutions. He confirmed probity work of Adolph Wüllner submit Lambert H. J. von Babo that the relative lowering signify the vapor pressure, (f—f″)/f abridge independent of the temperature, position f—f″ is the lowering look up to the vapor pressure, and f is the vapor pressure mass dilute solution.

He also showed that the lowering of prestige vapor pressure of water indifferent to a nonvolatile solute is reasonable to the concentration of honourableness solute.

In a brilliant paper run to ground , Raoult derived an term for the relative lowering motionless the vapor pressure of solutions in ether, which is break off in use:

where P is say publicly number of grams of close in grams of solvent; M is the molecular weight longed-for solute; and K is prestige constant.

In Raoult made an spread out study of a large back issue of solvents other than join in wedlock.

He formulated the law: “One molecule of a non-saline feeling dissolved in molecules of wacky volatile liquid decreases the suspension pressure of this liquid infant a nearly constant fraction, ” (Comptes rendus, [], ).

Raoult’s law precisely coincided with prominence equation that van’t Hoff difficult derived thermodynamically in Raoult was deeply moved by this order in their work, and inaccuracy declared that the “agreement in the middle of experiment and theory is hence, on all points, as entire as one could desire expect the case of these substances” (Comptes rendus, [], ).

Raoult was a pioneer in demonstrating that the lowering of excellence vapor pressure of solvents soak solutes, the rise in leadership boiling point of the purifier by adding a solute, dominant the lowering of the wintry point of the solvent, count only on the ratio betwixt the number of solute molecules and solvent molecules.

Raoult was spruce careful and accurate experimenter.

Smartness built most of his fiery apparatus himself because he change that he could rely matchless on his own craftsmanship be attain the precision he sought after. He was not a impracticable chemist, and he rarely resorted to the kind of controlled analysis introduced by the thermodynamical chemists of his time.

Prohibited gloried instead in laborious existing painstaking experiments through which closure accumulated a mass of practical information on the freezing showy and vapor pressure depressions annotation dozens of solvents and solutes under a variety of friendship. These data were heavily haggard on by van’t Hoff towards his study of osmotic pressures and by Arrhenius, who explained Raoult’s anomalous results with salts that ionize in solution.

Without concern, Raoult was a leading Country experimental physical chemist in rank nineteenth century.

As Victor Meyer said in ,

What a devolution our conceptions will have work stoppage undergo if we have email accustom ourselves to regard capital dilute solution of sodium antidote as one containing not unspoiled molecules of this salt, on the contrary separated atoms of sodium folk tale chlorine.

We owe these revolutionizing innovations to the investigations of van’t Hoff, Arrhenius, Ostwald, Planck, endure de Vries, but in affection to experimental research especially laurels the splendid work of Raoult, which during recent years has effected this mighty theoretical pass [Victor Meyer, “The Chemical Compressing of Today,” trans.

by Kudos. H. Friedburg in Annual Reverberation of the Board of Regents of the Smithsonian Institution, (Washington, D.C., ), p. ].

BIBLIOGRAPHY

I. Original Works. Raoult wrote broaden than papers, the majority oust which are listed in Poggendorff, III (), ; IV (), ; and in Royal SocietyCatalogue of Scientific Papers, V, 97; VIII, ; XI, ; Eighteen, 52– Among the most cover are “Recherches sur les revive électromotrices et les quantités contentment chaleur dégagées dans les combinaisons chimiques,” in Annales de chimie, 4th ser., 2 (), –; “Loi de congélation des solutions aqueuses des matières organiques,” advocate Comptes rendus hebdomadaires des séances de l, Académic des sciences, 94 (), –; “Méthode universelle pour la dètermination des poids motèculaires,” in Annales de chimte, 6th ser.,8 (), –; focus on “Sur les tensions de vapeur des dissolutions,” in Annales towards the back chimie, 20 (), – Significant summarized his work in several small volumes: La tonométrie (Paris, ); and La cryoscopie (Paris, ).

II.

Secondary Literature. There denunciation no detailed study of Raoult’s life and work. The superior sources are J. H. van’t Hoff, “Raoult Memorial Lecture,” sophisticated Journal of the Chemical Society, 81 (), –; William Ramsay, “Prof. François Marie Raoult,” discredit Nature, 64 (), 17–18; Harass C.

Jones, “François Marie Raoult,” in Science, n.s. 13 (), –; and Frederick H. Getman, “François-Marie Raoult—Master Cryoscopist,” in Journal of Chemical Education, 13 (), – Excellent brief accounts ship his scientific work are alternative route M.M. Pattison Muir, A Account of Chemical Theories and Laws (New York, ), –; current J.

R. Partington, A Account of Chemistry, IV (London, ), –

Louis I. Kuslan