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Le Châtelier's principle

(Encyclopedia)Le Châtelier's principle, chemical principle that states that if a system in equilibrium is disturbed by changes in determining factors, such as temperature, pressure, and concentration of components...

entropy

(Encyclopedia)entropy ĕnˈtrəpē [key], quantity specifying the amount of disorder or randomness in a system bearing energy or information. Originally defined in thermodynamics in terms of heat and temperature, e...

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...

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 ...

X ray

(Encyclopedia)CE5 Typical X-ray composite spectrum (intensity as a function of frequency) X ray, invisible, highly penetrating electromagnetic radiation of much shorter wavelength (higher frequency) than visibl...

artificial intelligence

(Encyclopedia)artificial intelligence (AI), the use of computers to model the behavioral aspects of human reasoning and learning. Research in AI is concentrated in some half-dozen areas. In problem solving, one mus...

Johnston, Joseph Eggleston

(Encyclopedia)Johnston, Joseph Eggleston, 1807–91, Confederate general, b. Prince Edward co., Va., grad. West Point, 1829. He served against the Seminole in Florida and with distinction under Winfield Scott in th...

Brown v. Board of Education of Topeka, Kans.

(Encyclopedia)Brown v. Board of Education of Topeka, Kans., case decided by the U.S. Supreme Court in 1954. Linda Brown was denied admission to her local elementary school in Topeka because she was black. When, com...

lusterware

(Encyclopedia)lusterware, kind of pottery with an overglaze finish containing copper and silver or other materials that give the effect of iridescence. The process may have been invented and was certainly first pop...

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