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cream of tartar

(Encyclopedia)cream of tartar, white crystalline powder. Chemically it is potassium hydrogen tartrate, KC4H5O6, the acidic potassium salt of tartaric acid. It is used as the leavening agent in baking powders. An im...

interstellar matter

(Encyclopedia)interstellar matter, matter in a galaxy between the stars, known also as the interstellar medium. The interstellar gas, which constitutes about 99% of the interstellar matter, consists mostly of hyd...

photosynthesis

(Encyclopedia)photosynthesis fōˌtōsĭnˈthəsĭs [key], process in which green plants, algae, and cyanobacteria utilize the energy of sunlight to manufacture carbohydrates from carbon dioxide and water in the pr...

oxidation and reduction

(Encyclopedia)oxidation and reduction, complementary chemical reactions characterized by the loss or gain, respectively, of one or more electrons by an atom or molecule. Originally the term oxidation was used to re...

calorimetry

(Encyclopedia)calorimetry kălˌərĭmˈətrē [key], measurement of heat and the determination of heat capacity. Heat is evolved in exothermic processes and absorbed in endothermic processes; such processes includ...

iodoform

(Encyclopedia)iodoform īōˈdəfôrmˌ [key], CHI3, yellow crystalline solid that has a penetrating odor. It melts at 119℃ and is insoluble in water but soluble in ether or ethanol. Iodoform was formerly used as...

Landau, Lev Davidovich

(Encyclopedia)Landau, Lev Davidovich lyĕf dəvēˈdəvĭch ləndouˈ [key], 1908–68, Soviet physicist, b. Baku, Azerbaijan. A child prodigy in mathematics, he entered Baku Univ. at 14; at 21 he received a doctor...

Fitch, Val Logsdon

(Encyclopedia)Fitch, Val Logsdon, 1923–2015, American nuclear physicist, b. Merriman, Neb., Ph.D. Columbia, 1954. During World War II Fitch was drafted into the army and worked on the detonator for the atomic bom...

methyl

(Encyclopedia)methyl mĕthˈəl [key], CH3, organic free radical or alkyl group derived from methane by the removal of one hydrogen atom. ...

Ångström, Anders Jöns

(Encyclopedia)Ångström, Anders Jöns änˈdərs yöns ōngˈström [key], 1814–74, Swedish physicist. He was educated at the Univ. of Uppsala and in 1839 became a member of its faculty. He is particularly noted...