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gasoline

(Encyclopedia)gasoline or petrol, light, volatile mixture of hydrocarbons for use in the internal-combustion engine and as an organic solvent, obtained primarily by fractional distillation and “cracking” of pet...

Krebs cycle

(Encyclopedia)Krebs cycle, series of chemical reactions carried out in the living cell; in most higher animals, including humans, it is essential for the oxidative metabolism of glucose and other simple sugars. The...

Kivu, lake, Congo and Rwanda

(Encyclopedia)Kivu, lake, 1,042 sq mi (2,699 sq km), 55 mi (89 km) long, on the Congo-Rwanda border, E central Africa; highest lake in Africa (4,788 ft/1,459 m). It is drained by the Ruzizi River, which flows S int...

white dwarf

(Encyclopedia)white dwarf, in astronomy, a type of star that is abnormally faint for its white-hot temperature (see mass-luminosity relation). Typically, a white dwarf star has the mass of the sun and the radius of...

Ogden, city, United States

(Encyclopedia)Ogden, city (1990 pop. 63,909), seat of Weber co., N Utah, at the confluence of the Ogden and Weber rivers; inc. 1851. Aerospace industries and Hill Air Force Base are the major employers. There is we...

Manabe, Syukuro

(Encyclopedia)Manabe, Syukuro, 1931– , Japanese climatologist and meteorologist, D.Sc. University of Tokyo, 1958. Manabe has been instrumental in the development of...

calcium carbonate

(Encyclopedia)calcium carbonate, CaCO3, white chemical compound that is the most common nonsiliceous mineral. It occurs in two crystal forms: calcite, which is hexagonal, and aragonite, which is rhombohedral. Calci...

biosphere

(Encyclopedia)biosphere, irregularly shaped envelope of the earth's air, water, and land encompassing the heights and depths at which living things exist. The biosphere is a closed and self-regulating system (see e...

Berthelot, Pierre Eugène Marcelin

(Encyclopedia)Berthelot, Pierre Eugène Marcelin pyĕr ûzhĕnˈ märsəlăNˈ bĕrtəlōˈ [key], 1827–1907, French chemist. He was professor at the École Supérieure de Pharmacie (1859) and at the Collège de ...

diffusion

(Encyclopedia)diffusion, in chemistry, the spontaneous migration of substances from regions where their concentration is high to regions where their concentration is low. Diffusion is important in many life process...