Medical Dictionary

Raoult's law

noun Ra·oult's law \rä-ˈülz-\

Medical Definition of Raoult's law

  1. :  a law in physical chemistry: the fraction by which the vapor pressure of a liquid is lowered when a small amount of a substance that is nonvolatile, not capable of being dissociated, and usually not a high polymer is dissolved in it is equal to the ratio of the number of moles of the solute to the total number of moles of all components of the solution

Biographical Note for raoult's law




(1830–1901), French chemist. Raoult is known for developing the theory of solutions. He discovered about 1886 that the freezing point of an aqueous solution is lowered in proportion to the amount of nonelectrolyte dissolved. He recognized that the effect of the amount of solute dissolved on the solvent's freezing point was due to a change in the vapor pressure of the solvent brought about by the presence of the solute. This recognition led to the formulation of Raoult's law. The law made possible the determining of molecular weights of dissolved substances.

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