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Edison, Thomas Alva

(Encyclopedia)Edison, Thomas Alva, 1847–1931, American inventor, b. Milan, Ohio. A genius in the practical application of scientific principles, Edison was one of the greatest and most productive inventors of his...

halogen

(Encyclopedia)halogen hălˈəjĕn [key] [Gr.,=salt-bearing], any of the chemically active elements found in Group 17 of the periodic table; the name applies especially to fluorine (symbol F), chlorine (Cl), bromin...

nitric oxide

(Encyclopedia)nitric oxide or nitrogen monoxide, a colorless gas formed by the combustion of nitrogen and oxygen as given by the reaction: energy + N2 + O2 → 2NO; m.p. −163.6℃; b.p. −151.8℃. Nitric oxide ...

smog

(Encyclopedia)smog smŏg [key] [smoke+fog], dense, visible air pollution. Smog is commonly of two types. The gray smog of older industrial cities like London and New York derives from the massive combustion of coal...

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 ...

methanol

(Encyclopedia)methanol, methyl alcohol, or wood alcohol, CH3OH, a colorless, flammable liquid that is miscible with water in all proportions. Methanol is a monohydric alcohol. It melts at −97.8℃ and boils at 6...

fallout

(Encyclopedia)fallout, minute particles of radioactive material produced by nuclear explosions (see atomic bomb; hydrogen bomb; Chernobyl) or by discharge from nuclear-power or atomic installations and scattered th...

alkyl group

(Encyclopedia)alkyl group ălˈkĭl [key], in chemistry, group of carbon and hydrogen atoms derived from an alkane molecule by removing one hydrogen atom (see radical). The name of the alkyl group is derived from t...

dry cleaning

(Encyclopedia)dry cleaning, process of cleaning fabrics without water. Special solvents and soaps are used so as not to harm fabrics and dyes that will not withstand the effects of ordinary soap and water. Dry clea...

electrode

(Encyclopedia)electrode, terminal through which electric current passes between metallic and nonmetallic parts of an electric circuit. In most familiar circuits current is carried by metallic conductors, but in som...