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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    anrl charcoal to bright redness, and pnssing a stream of drj' Clilorhie over it.] B and F. [Boron fluoride BF3 = 6». A colorless gas, irritating, fuming. Water dissolves 700 times its volunie, producing a i'uining liquid of sp. gr. 1.77. The elements of water make it into BjOs.fiHF, really the character of the solution. Prep, of BF3. By igniting a mixture of calcium fluoride with boracic anhychide. sCaF^ + 4B2O3 = 3Ca2B02+ 2BF3. When BF3, dissolved in niucli'water, fluo- boric acid HF.BFj, is obtained with free bor;icie acid. (BF^ + f.OHj = :(B()2H,0I-L) + 6(HF,BF3). Boion made from potas- SICM BoROFLUOEiDE KF,I3F3, by heating with K.] Xin. Silicon Si = 28. Tetrad element, never native. Discovered by Berzelius in 1823. Combined with oxygen, silicon forms silica or silicic an- hydride, one of the most abundant minerals. Like boron, two distinct modifications of silicon are known, a. Amorphous silicon. BriDwn powder, insoluble in, and denser than, water. A non- conductor of electricity. Soils the fingers. Intact in nitric or sulphuric acids : readily removed as gaseous Silicon fluoride by Hydrogen fluoride. Burns brilliantly wlien heated in air Prej). by heating Potassium with Potassium silico-fluoride: ^(KFjSiF^ 4- 4K0 = loKF + Si2. h. Crystalline silicon. Sti el-grey, metalline, and' a conductor of electiicitv. Sp. gr. 2.49, Not attacked when fused with NO2OK or C10,'0K. Heated in Ch, into SiCl^; in a stream of CIH into Silicon-chloroform SiHClj and hydrogen. Prep, by heating in a red-hot crucible a mixture of jjotas^ium silico-fluoride, sodium and granulated zinc: Ihe liljerated Si dissolves in the zinc. Tlie latter is removed by CIH. Compounds. Si and H. [Silicon hydride SiH^ = 32. Coloiless gas, which only takes fire spontaneously in air when free H is present. Passed through a red-hot tube, it is decomposed into Si and 2H„. Impure it is obtained from mngnc slum silicideimd CIH ; always accompanied by free H.] Si ami 0. Silicic anhydride or Silica SiOj = 60. In two modifications, crystalline and amorphous. As rock-crystal, in G-sided, transveisely striated prisms, ter- minated by 6-sidod pyi-amids. Sp. gr. 2.69. Insoluble in water, and in all acids, except hydrogen fluoride, which volatilizes the silicon as fluoride Amelhyst. cairngorm, agate, flint, carnelian, onyx, chalcedony, are varieties more or less pure of quartz, or silica. Opal contains about 10 per cent, of water. Fusible in oxy- hydrog, n. Amorphous silica is a fine, white, tasteless powder, obtainable from either of the hydrogen silicates by a gentle heat. When once heateil to redness, FIl is its only solvent, by de- composition. Coiniwsition of the hydrates of silica doubtful. OH2,3SiO.,, and 0H2,4Si02. Silicates. Clay, felspar, mica, &c.,