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charcoal

(Encyclopedia)charcoal, substance obtained by partial burning or carbonization (destructive distillation) of organic material. It is largely pure carbon. The entry of air during the carbonization process is control...

ozone layer

(Encyclopedia)ozone layer or ozonosphere, region of the stratosphere containing relatively high concentrations of ozone, located at altitudes of 12–30 mi (19–48 km) above the earth's surface. Ozone in the ozone...

iodine

(Encyclopedia)iodine īˈədīn, –dĭn [key] [Gr.,=violet], nonmetallic chemical element; symbol I; at. no. 53; at. wt. 126.90447; m.p. 113.5℃; b.p. 184.35℃; sp. gr. 4.93 at 20℃; valence −1, +1, +3, +5, o...

respiration

(Encyclopedia)CE5 Respiratory system respiration, process by which an organism exchanges gases with its environment. The term now refers to the overall process by which oxygen is abstracted from air and is tran...

battery, electric

(Encyclopedia)CE5 Lead storage cell: At the lead-dioxide electrode, electrons from the circuit combine with lead dioxide and sulfuric acid to form lead sulfate and water. At the spongy-lead electrode, lead react...

Sanger, Frederick

(Encyclopedia)Sanger, Frederick săngˈər [key], 1918–2013, British biochemist, grad. Cambridge (B.A., 1939; Ph.D., 1943). He continued his research at Cambridge after 1943. He won the 1958 Nobel Prize in Chemis...

citron

(Encyclopedia)citron sĭtˈrən [key], name for a tree (Citrus medica) of the family Rutaceae (orange family), and for its fruit, the earliest of the citrus fruits to be introduced to Europe from Asia. The small ev...

ethylene

(Encyclopedia)ethylene ĕthˈēn [key], H2C=CH2, a gaseous unsaturated hydrocarbon. It is the simplest alkene. Ethylene is colorless, has a faint odor, and has a slightly sweet taste; it melts at −169.4℃ and bo...

tung oil

(Encyclopedia)tung oil, oil obtained from the seeds of a tropical tree, the tung tree (Aleurites fordii) of the spurge family, and from seeds of some related species, all from Indomalesia or W Pacifica. It is known...

valine

(Encyclopedia)CE5 valine vălˈēn [key], organic compound, one of the 22 α-amino acids commonly found in animal proteins. Only the l-stereoisomer appears in mammalian protein. It is one of several essential am...