| van't Hoff's law | In stereochemistry, all optically active substances have one or more multivalent atoms united to four different atoms or radicals so as to form in space an unsymmetrical arrangement, the osmotic pressure exerted by any substance in very dilute solution is the same that it would exert if present as gas in the same volume as that of the solution; or, at constant temperature, the osmotic pressure of dilute solutions is proportional to the concentration (number of molecules) of the dissolved substance; i.e., the osmotic pressure, π, in dilute solutions is π = RTσci, where R is the universal gas constant, T is the absolute temperature, and ci is the molar concentration of solute i, the rate of chemical reactions increases between two-and three-fold for each 10캜 rise in temperature. (05 Mar 2000) |
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| Gay-Lussac's law | All gases expand equally on heating, namely, 1/273.16 of their volume at 0캜 for every degree Celsius. Synonym: Gay-Lussac's law. (05 Mar 2000) |
| Raoult's law | The vapor pressure of a solution of a nonvolatile nonelectrolyte is that of the pure solvent multiplied by the mole-fraction of the solvent in the solution. (05 Mar 2000) |
| Marey's law | The pulse rate varies inversely with the blood pressure; i.e., the pulse is slow when the pressure is high; an expression of baroreceptor reflex influences on heart rate. (05 Mar 2000) |
| Marfan's law | The healing of localised tuberculosis protects against subsequent development of pulmonary tuberculosis. (05 Mar 2000) |
| mariotte's law | <physics> See Boyle's law, under Law. Source: Websters Dictionary (01 Mar 1998) |
| reciprocity law | In two photochemical reactions, e.g., the darkening of a photographic plate or film, if the product of the intensity of illumination and the time of exposure are equal, the quantities of chemical material undergoing change will be equal; the retina for short periods of exposure obeys this law. Synonym: reciprocity law, Roscoe-Bunsen law. (05 Mar 2000) |
| Gerhardt-Semon law | <otolaryngology> An obsolete law formerly used to account for the position of an affected vocal cord or cords after injury to the recurrent laryngeal nerve or nerves. (05 Mar 2000) |
| mass law | <chemistry> This law states that the rate of a given chemical reaction is proportional to concentration of the reactants. (09 Oct 1997) |
| Pascal's law | Fluids at rest transmit pressure equally in every direction. (05 Mar 2000) |
| Virchow's law | There is no special or distinctive neoplastic cell, inasmuch as the component cells of neoplasms originate from preexisting forms. (05 Mar 2000) |
| Vogel's law | When a phenotype may be transmitted by various modes of mendelian inheritance, the dominant will have the least deleterious phenotype, the recessive the most, and the X-linked intermediate between the two. (05 Mar 2000) |
| Godelier's law | Tuberculosis of the peritoneum is always associated with tuberculosis of the pleura on one or both sides. (05 Mar 2000) |
| Meltzer's law | "all living functions are continually controlled by two opposite forces: augmentation or action on the one hand, and inhibition on the other." Synonym: law of contrary innervation. (05 Mar 2000) |
| Gompertz' law | The proportional relationship of mortality to age; after age 35-40, the increase in mortality with age tends to be logarithmic. (05 Mar 2000) |