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ammonium nitrate

(Encyclopedia)ammonium nitrate, chemical compound, NH4NO3, that exists as colorless, rhombohedral crystals at room temperature but changes to monoclinic crystals when heated above 32℃. It is extremely soluble in ...

flame test

(Encyclopedia)flame test, test used in the identification of certain metals. It is based on the observation that light emitted by any element gives a unique spectrum when passed through a spectroscope. When a salt ...

isopropanol

(Encyclopedia)isopropanol, isopropyl alcohol, or 2-propanol īˌsəprōˈpənōl, īˌsəprōˈpĭl [key], (CH3)2CHOH, a colorless liquid that is miscible with water. It melts at −89℃ and boils at 82.3℃. It ...

electrolyte

(Encyclopedia)electrolyte ĭlĕkˈtrəlītˌ [key], electrical conductor in which current is carried by ions rather than by free electrons (as in a metal). Electrolytes include water solutions of acids, bases, or s...

pasteurization

(Encyclopedia)pasteurization păsˌcho͝orĭzāˈshən, –rīzāˈshən [key], partial sterilization of liquids such as milk, orange juice, wine, and beer, as well as cheese, to destroy disease-causing and other u...

purine

(Encyclopedia)CE5 Purines found in deoxyribonucleic acid (DNA) purine, type of organic base found in the nucleotides and nucleic acids of plant and animal tissue. The German chemist Emil Fischer did much of the...

Richards, Ann Willis

(Encyclopedia)Richards, Ann Willis, 1933–2006, American politician, b. Lakeview, Tex., as Dorothy Ann Willis. She began her career in politics in the early 1970s after having raised four children. A Democrat, she...

paraldehyde

(Encyclopedia)paraldehyde pârălˈdəhīdˌ [key], nervous system depressant similar to alcohol in its effects and used as a sedative. A colorless flammable liquid with a disagreeable odor, paraldehyde produces sl...

palmitin

(Encyclopedia)palmitin pălˈmətĭn [key], fat that is the triglyceride of palmitic acid, CH3(CH2)14CO2H, i.e., the tripalmitate ester of glycerol. It is a white crystalline solid at ordinary temperatures, insolub...

viscose process

(Encyclopedia)viscose process vĭsˈkōs [key], method widely used for the commercial preparation of rayon. Cellulose, prepared from either wood pulp or, less commonly, cotton linters, is treated with sodium hydrox...