RAOULT, F.-M. (FRANCOIS MARIE). - DISCOVERY OF RAOULT'S LAWS.

Loi générale de congélation des dissolvants, Mémoire de... (Extrait par l'auteur). (+) Loi générale des tensions de vapeur des dissolvants. (2 Papers).

(Paris, Gauthier-Villars), 1882. 4to. No wrappers. In: "Comptes Rendus Hebdomadaires des Séances de L'Academie des Sciences", Tome 95, No 22 a. Tome 104 No 21 (entire issues offered). Pp. 1017-1076 and pp. 1387-1462. Raoult's papers: pp. 1030-33 (tome 95) and pp. 1430-1433 (tome 104).

First appearance of Raoult's two importent papers in which described a method for finding the molecular weight of an organic compound by the determination of the lowering of the freezing point of water that resulted from dissolving that compound in water and the law governing the relation between solutes and vapor pressure.

"Then in 1882, F.-M. Raoult published his results on the effects of nondissociating organic solutes, from which he deduced a general law controlling the lowering of freezing points (the first paper offered). Four years later he extended this work to show the effect of solutes on vapor pressure (the second paper offered). Having established the effect of nondissociating compounds, he was in position to show that salts produced an eeffect which, though anomalous, could nevertheless be explained by the supposition that a dissolved molecule broke up into other molecules. This work was of great value in supplying a new method for determining molecular weights, since the depression of freezing point and vapor pressure (as well a the related rise in boiling point later discovered) are proportional to the moleculat concentrations ofthe solutions; it was of equal value in supporting the ideas of van't Hoff on osmotic pressure. With the announcement of the dissociation theory of Arrhenius, the anomalies were explained and the full significance of the generalizations of Raoult was recognized. Raoult published the formulations of his laws in the "Comptes Rendus" for 1882 and 1887 (the papers offered)" (Leicester a. Klickstein "A Source Book in Chemistry", pp. 471 ff).

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