| 释义 |
ammonia|əˈməʊnɪə|
[a. mod.L. ammonia, invented by Bergman, in 1782, as a name for the gas obtained from sal ammoniac: see next.]
1. A colourless gas with pungent smell and strong alkaline reaction, chemically a compound of three equivalents of hydrogen with one of nitrogen, NH3, which at a pressure of 6½ atmospheres, at 50° Fahr., is condensed to a colourless liquid. Called also spirit of hartshorn, in allusion to one of its early sources, the dry distillation of nitrogenous matter, as the hoofs and horns of animals; and volatile or animal alkali, in contradistinction to the ‘fixed’ alkalis, potash or ‘vegetable’ alkali, and soda or ‘mineral’ alkali.
1799A. Aikin Syllabus Lect. Chem. 7 Ammonia, or Volatile Alkali. 1801Hatchett in Phil. Trans. XCII. 50 Ammonia formed a yellow flocculent precipitate. 1810Dalton Syst. Chem. Philos. ii. v. §6. 415 It has been long known to chemists as an important element, and under various names,..namely, volatile alkali, hartshorn, spirit of sal ammoniac, etc., but authors at present generally distinguish it by the name of ammonia. 1822J. Flint Lett. fr. Amer. 62 A chemical manufactory in which ammonia, copperas..and various acids, are prepared. 1855Bain Senses & Int. ii. ii. §1 In smelling salts, ammonia is the substance given forth.
2. pop. ammonia, or specifically liquid ammonia: a solution of ammonia in water, being the form in which it is commercially used.
c1850J. Griffin in Ure Dict. Arts I. 140 To judge at a glance of the money value of any given sample of ammonia. 1863Watts Dict. Chem. (1872) I. 184 Solution of ammonia, Aqueous ammonia, or simply Ammonia, Spirits of hartshorn.
3. Chem. Extended to a large series of compounds, analogous to ammonia, in which one or more of the three hydrogen atoms of NH3 are replaced by a basic metal or radical (amines), or by the oxygenized radical of an acid (amides), or by both at once (alkalamides).
1863Watts Dict. Chem. (1872) I. 169 Ammonias in which 1 or more atoms of hydrogen are replaced by an acid-radicle. 1869Roscoe Elem. Chem. xxix. 312 Each alcohol also forms a series of compound ammonias.
4. Comb. in which ammonia stands chiefly in attrib. relation, as ammonia gas, ammonia compounds, ammonia process, ammonia solution, ammonia substitution compound, ammonia works, etc. Also ammonia alum, ammonia amalgam, ammonia carbonate, ammonia salts, etc., in which ammonium is now used in more systematic nomenclature. ammonia-meter, an instrument for measuring the percentage of ammonia in an aqueous solution.
1873Fownes Chem. 156 Ammonia gas is colourless. 1879Athenæum 30 Aug. 277/3 The ‘ammonia process’—which has been developed by M. Ernest Solvay, of Brussels. 1864Reader 9 April 464 The pale reddish amethystine colour of ammonia-iron-alum. 1849M. Somerville Connex. Phys. Sc. xxiv. 227 Paper prepared with the ammonia-citrate of iron. 1875Ure Dict. Arts I. 140 Mr. J. J. Griffin has constructed a useful instrument called an Ammonia-meter. |