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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...

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...

ammonia

(Encyclopedia)ammonia, chemical compound, NH3, colorless gas that is about one half as dense as air at ordinary temperatures and pressures. It has a characteristic pungent, penetrating odor. Ammonia forms a minute ...

deuterium

(Encyclopedia)deuterium do͞otērˈēəm [key], isotope of hydrogen with mass no. 2. The deuterium nucleus, called a deuteron, contains one proton and one neutron. Deuterium is also called heavy hydrogen, and water...

Central Utah project

(Encyclopedia)Central Utah project, N central Utah; begun 1959 near Vernal, Utah, by the U.S. Bureau of Reclamation in conjunction with the Colorado River storage project. Water, collected from streams in the Uinta...

Sevan

(Encyclopedia)Sevan syĭvänˈ [key], lake, c.540 sq mi (1,400 sq km), NE Armenia, at an altitude of 6,280 ft (1,914 m); it is 324 ft (99 m) deep. The largest lake of the Caucasus, it is fed by some 30 streams, but...

Central Valley project

(Encyclopedia)Central Valley project, central Calif., long-term general scheme for the utilization of the water of the Sacramento River basin in the north for the benefit of the farmlands of the San Joaquin Valley ...