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Ponca City

(Encyclopedia)Ponca City, city (1990 pop. 26,359), Kay co., N Okla., on the Arkansas River; founded 1893 with the opening of the Cherokee Strip, inc. 1899. It is a trade, processing, and shipping hub in a grain, li...

hydrate

(Encyclopedia)hydrate hīˈdrāt [key], chemical compound that contains water. A common hydrate is the familiar blue vitriol, a crystalline form of cupric sulfate. Chemically, it is cupric sulfate pentahydrate, CuS...

microphone

(Encyclopedia)microphone, device for converting sound into electrical energy, used in radio broadcasting, recording, and sound amplifying systems. Its basic component is a diaphragm that responds to the pressure or...

inorganic chemistry

(Encyclopedia)inorganic chemistry, the study of all the elements and their compounds with the exception of carbon and its compounds, which fall under the category of organic chemistry. Inorganic chemistry investiga...

Lynen, Feodor

(Encyclopedia)Lynen, Feodor fāōˈdôr lēˈnən [key], 1911–79, German biochemist, grad. Univ. of Munich (Ph.D. 1937). He began teaching at the Max Planck Institute for Cell Chemistry in Munich in 1947. His res...

silicon

(Encyclopedia)silicon, nonmetallic chemical element; symbol Si; at. no. 14; interval in which at. wt. ranges 28.084–28.086; m.p. 1,410℃; b.p. 2,355℃; sp. gr. 2.33 at 25℃; valence usually +4. Silicon is the ...

fire fighting

(Encyclopedia)fire fighting, the use of strategy, personnel, and apparatus to extinguish, to confine, or to escape from fire. Ancient Rome is known to have had a fire department consisting by the 1st cent. of app...

Kekulé von Stradonitz, Friedrich August

(Encyclopedia)Kekulé von Stradonitz, Friedrich August frēˈdrĭkh ouˈgo͝ost kāˈko͞olā fən shträˈdōnĭts [key], 1829–96, German organic chemist. He was professor at Ghent (1858–65) and at Bonn from 1...

leaven

(Encyclopedia)leaven lĕvˈən [key], agent used to raise bread or other flour foods. Physical leavens include water vapor, which is released as steam at high temperatures (as in popovers), and air, which is incorp...

Le Bel, Joseph Achille

(Encyclopedia)Le Bel, Joseph Achille zhôsĕfˈ äshēlˈ ləbĕl [key], 1847–1930, French chemist. He was educated at the École polytechnique and carried out much of his research in his own private laboratory. ...

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