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acids and bases

(Encyclopedia)acids and bases, two related classes of chemicals; the members of each class have a number of common properties when dissolved in a solvent, usually water. Another theory that provides a very broad ...

deliquescence

(Encyclopedia)deliquescence dĕlˌəkwĕsˈəns [key], conversion of a solid substance into a liquid as a result of absorption of water vapor from the air. Since impurities in a solid lower its melting point, the a...

eutrophication

(Encyclopedia)eutrophication yo͞otrōˌfĭkāˈshən [key], aging of a lake by biological enrichment of its water. In a young lake the water is cold and clear, supporting little life. With time, streams draining i...

hydrogen fluoride

(Encyclopedia)hydrogen fluoride, chemical compound, HF, a colorless, fuming liquid or colorless gas that boils at 19.54℃. It is miscible with water and is soluble in benzene, toluene, and concentrated sulfuric ac...

fluoridation

(Encyclopedia)fluoridation flo͝orˌĭdāˈshən [key], process of adding a fluoride to the water supply of a community to preserve the teeth of the inhabitants. Tooth enamel ordinarily contains small amounts of fl...

Fermat, Pierre de

(Encyclopedia)Fermat, Pierre de pyĕr də fĕrmäˈ [key], 1601–65, French mathematician. A magistrate whose avocation was mathematics, Fermat is known as a founder of modern number theory and probability theory....

Philo

(Encyclopedia)Philo jo͞odēˈəs [key] [Lat.,=Philo the Jew], c.20 b.c.–c.a.d. 50, Alexandrian Jewish philosopher. His writings have had an enormous influence on both Jewish and Christian thought, and particular...

Witte, Count Sergei Yulyevich

(Encyclopedia)Witte, Count Sergei Yulyevich syĭrgāˈ yo͞oˈlyĭvĭch vĭtˈə [key], 1849–1915, Russian premier. A railway administrator, he became minister of communications (1892) and minister of finance (18...

Reinhardt, Max

(Encyclopedia)Reinhardt, Max, 1873–1943, Austrian theatrical producer and director, originally named Max Goldmann. After acting under Otto Brahm at the Deutsches Theater in Berlin, he managed (1902–5) his own t...

oxide

(Encyclopedia)oxide, chemical compound containing oxygen and one other chemical element. Oxides are widely and abundantly distributed in nature. Water is the oxide of hydrogen. Silicon dioxide is the major componen...