Notes for students in chemistry : being a syllabus of chemistry compiled mainly from the manuals of Fownes-Watts, Miller, Wurz, and Schorlemmer / by Albert James Bernays.

  • Albert Bernays
Date:
1878
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Licence: Public Domain Mark

Credit: Notes for students in chemistry : being a syllabus of chemistry compiled mainly from the manuals of Fownes-Watts, Miller, Wurz, and Schorlemmer / by Albert James Bernays. Source: Wellcome Collection.

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    the oblique rhombic prism; selenite, augite, spheiie :—and fhe oblique rhombic octahedron; felspar, nelenit.e, &c.—VI. The doubly oblique or anorthic system. All the axes of unequal length and all cros.s obliquely. Includes: the doubly oblique prism ; axinite, blue vitriol, &c.:—and the doubly oblique octa- hedron ; albite, axinite.] When a body crystallizes in two irreconcilable forms, it is said to be DiMORPHors; when in three, TRnionpuoi s. Pulveru- lent bodies, without any regular form, are called amorphous. Crystallized bodies, with similarity in form and analogy of composition, are called isomorphous. E.g. KCl. KI. KF. K(CN). The metals combine together to form alloys : they are not so well-defined as those of the metals with 0, S, Se, CI, Br, I, F, &c. Tlie melting-point is often below that of the constituent metals. Alloys of mercury called amalgams. Metals of the alkalies. Symbol. At. weight. Sp. gr. Potassium . . K = 39-1 • . 0.865 Sodium . Na = 23. . • 0-972 Lithium . . L 7 • . 0.593 Caesium . Cs = 133 Rubidium . . Rb = 85.4 . . 1.520 (Ammonium) . H,N = 18 I. Group. Metals of the alkalies. They displace one atom of H from the H of the hydi-oxyl, or the H of the acids: hence monovalent. Their basic oxides and hydroxides are very soluble in water, and strongly alkaline to test-paper. Their carbonates are also soluble and alkaline. I. Potassium or Kalium K = 39.1. =78.2. Discovered by Davy in 1807. Never native. Brillmntly- white metal, volatile at a red-heat, with green vapor. Sp. gr. 0.865. Melts 62°,5 C. Oxydizes so rapidly that it must be kept imder naphtha, or hermetically sealed Decomposes 0H„, the H burning with rose-colored flame in air, and dissolves as hydroxide KOH. Absorbs CO, and yields potassium rhodizonate C504H„(OK)„,OH.,. Frcp. 1. By electrolysis of moist KOH : Kj at the zincode. 2. By strongly heating CO(OK)j with C, - 3C0-f K„. 3. By heating KOH to whiteness wnth iron- filings. 4KOH -1- 3Fe = Fe.O^ + 2H. + 2K„. Only one basic oxide. Three oxides. K„0. K,0„. K^O^. 1. Potassoxide K.,0 = 94.2. White, deliquescent caustic. Fuses at red-heat. By