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Sonora

(Encyclopedia)Sonora sōnōˈrä [key], state (1990 pop. 1,823,606), 70,484 sq mi (182,554 sq km), NW Mexico, on the Gulf of California, S of Arizona. Hermosillo is the capital. Sonora is mostly mountainous, with v...

promethium

(Encyclopedia)promethium prōmēˈthēəm [key], artificially produced radioactive chemical element; symbol Pm; at. no. 61; mass no. of most stable isotope 145; m.p. 1,042℃; b.p. 3,000℃ (estimated); sp. gr. unk...

calcium

(Encyclopedia)calcium kălˈsēəm [key] [Lat.,=lime], metallic chemical element; symbol Ca; at. no. 20; at. wt. 40.078; m.p. about 839℃; b.p. 1,484℃; sp. gr. 1.55 at 20℃; valence +2. Calcium is a malleable, ...

phosphorus

(Encyclopedia)phosphorus fŏsˈfərəs [key] [Gr.,=light-bearing], nonmetallic chemical element; symbol P; at. no. 15; at. wt. 30.97376; m.p. 44.1℃; b.p. about 280℃; sp. gr. 1.82 at 20℃; valence −3, +3, or ...

catalyst

(Encyclopedia)catalyst, substance that can cause a change in the rate of a chemical reaction without itself being consumed in the reaction; the changing of the reaction rate by use of a catalyst is called catalysis...

cold fusion

(Encyclopedia)cold fusion or low-temperature fusion, nuclear fusion of deuterium, an isotope of hydrogen, at or relatively near room temperature. Fusion, the reaction involved in the release of the destructive ener...

coin

(Encyclopedia)coin, piece of metal, usually a disk of gold, silver, nickel, bronze, copper, aluminum, or a combination of such metals, stamped by authority of a government as a guarantee of its real or exchange val...

Greenville

(Encyclopedia)Greenville. 1 City (2020 pop. 29,670, seat of Washington co., W Miss., on Lake Ferguson, a deepwater harbor adjoining the Mississippi River; inc. ...

flame

(Encyclopedia)flame, phenomenon associated with the chemical reaction of a gas that has been heated above its kindling temperature with some other gas, usually atmospheric oxygen (see combustion). The heat and ligh...

meteor

(Encyclopedia)meteor, appearance of a small particle flying through space that interacts with the earth's upper atmosphere. While still outside the atmosphere, the particle is known as a meteoroid. Countless meteor...