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molecular weight

(Encyclopedia)molecular weight, weight of a molecule of a substance expressed in atomic mass units (amu). The molecular weight may be calculated from the molecular formula of the substance; it is the sum of the ato...

fluorine

(Encyclopedia)fluorine flo͞oˈərēn, –rĭn [key], gaseous chemical element; symbol F; at. no. 9; at. wt. 18.9984; m.p. −219.6℃; b.p. −188.14℃; density 1.696 grams per liter at STP; valence −1. Fluorin...

valence, in chemistry

(Encyclopedia)valence, combining capacity of an atom expressed as the number of single bonds the atom can form or the number of electrons an element gives up or accepts when reacting to form a compound. Atoms are c...

Hertz, Gustav

(Encyclopedia)Hertz, Gustav go͝osˈtäf hĕrts [key], 1887–1975, German physicist. He is noted for his work on the atom, and he shared with James Franck the 1925 Nobel Prize in Physics for research (1914) on the...

acids and bases

(Encyclopedia)acids and bases, two related classes of chemicals; the members of each class have a number of common properties when dissolved in a solvent, usually water. Another theory that provides a very broad ...

hydrocyanic acid

(Encyclopedia)hydrocyanic acid hīˌdrōsīănˈĭk [key]: see hydrogen cyanide. ...

neutralization

(Encyclopedia)neutralization, chemical reaction, according to the Arrhenius theory of acids and bases, in which a water solution of acid is mixed with a water solution of base to form a salt and water; this reactio...

tracer

(Encyclopedia)tracer, an identifiable substance used to follow the course of a physical, chemical, or biological process. In chemistry the ideal tracer has the same chemical properties as the molecule it replaces a...

palladium, chemical element

(Encyclopedia)palladium [Gr. Pallas, goddess of wisdom], metallic chemical element; symbol Pd; at. no. 46; at. wt. 106.42; m.p. 1,554℃; b.p. 2,970℃; sp. gr. 12.02 at 20℃; valence +2, +3, or +4. Palladium is a...

carboxyl group

(Encyclopedia)carboxyl group kärbŏkˈsĭl [key], in chemistry, functional group that consists of a carbon atom joined to an oxygen atom by a double bond and to a hydroxyl group, OH, by a single bond. Carboxylic a...