Professor Dr. G. Jägers Monatsblatt : Zeitschrift für Gesundheitspflege u. Lebenslehre: Professor Dr. G. Jägers Monatsblatt : Zeitschrift für Gesundheitspflege u. Lebenslehre

Jaeger, Gustav

Professor Dr. G. Jägers Monatsblatt : Zeitschrift für Gesundheitspflege u. Lebenslehre (Jg. 1888, Bd. 7, H. 1/12)

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Persistenter Identifier:: 1580125921904

Titel:: Professor Dr. G. Jägers Monatsblatt : Zeitschrift für Gesundheitspflege u. Lebenslehre

Erscheinungsort:: Stuttgart

Erscheinungsverlauf:: 18XX

Strukturtyp:: Zeitschrift

Sammlung:: Zeitschriften

Lizenz:: https://creativecommons.org/publicdomain/mark/1.0/deed.de

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Persistenter Identifier:: 1580125921904_1888

Titel:: Professor Dr. G. Jägers Monatsblatt : Zeitschrift für Gesundheitspflege u. Lebenslehre

Autor:: Jaeger, Gustav

Jahrgang/Band:: Jg. 1888, Bd. 7, H. 1/12

Erscheinungsjahr:: 1888

Sprache:: deutsch

Strukturtyp:: Band

Standort:: Universitätsbibliothek Stuttgart

Signatur:: XIX/218.4-7,1888

Lizenz:: https://creativecommons.org/publicdomain/mark/1.0/deed.de

Sammlung:: Zeitschriften

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N+ I Electrolytic Determination of Copper. { Curmicat News, Dec. 9, 1881. 5. § h. I te 0'0322 0'0324 0°0346 00283 00088 0°0088 0'0094 0'00771 0'0054 0'00435 0°0074 00054 0'0006 0'0005 0'00082 0'0006 146 17'6 11°46 12°42 - Carbonic acid .. .. .. 0'0273 0'0316 0'0350 003.44 quivalent tocarbon .., 00744 Q'00862 0'00954 0°00938 ater... .. .. .. 00094 0°'0108 0'0089g 0°0094 Equivalent to hydrogen .. _ 0'00104 000120 0°00100 0'00104 Ratio of carbon to hydrogen 7°15 718 9°54 go Copper .. .. .. 09683 0°g68y Total .. .. .. .. 0'97884 0'g7912 be y nised as such by dissolving in dilute sulphuric acid and applying appropriate tests, In the presence of the organic acid the formation of peroxide of lead on the positive pole is hindered, and in its absence it is very difficult to precipitate the whole of the copper from the solution, In order to obtain sufficient material for analysis, to ascertain the cause of the excess in weight, the precipita- tion of the copper was made on a piece of platinum foil, On attempting to strip the deposit from the foil I found that it was extremely brittle, and scaled off easily,—so brittle, indeed, that it could be reduced to an impalpable powder in an agate mortar with very little trouble. This agrees exactly with the description of the allotropic copper of M. P. Schutzenberger, which was published in Comptes Rendus (vol. Ixxxvi,, part 2). M. Schutzenberger obtained the material he describes by the electrolysis of a 10 per cent solution of the neutral acetate of copper, He found that the produét contained from 5 to I0 per cent of sub- oxide of copper. In the material which I prepared from the nitric and citric acid solution I did not find any sub- oxide of copper; on the other hand, both carbon and hydrogen have been detected and estimated. These latter were determined by combustion of the finely divided sample in oxygen ; the method used to estimate the sub. oxide of copper was that of Hampe.* However oxygen is present, though, as this test shows, not as cuprous oxide. The results of the analyses of several samples, prepared at different times, are given above. The determinations were all made on the amount of t grm. The results which are bracketed are from duplicate analyses. These samples were all prepared from the nitric and citric acid solution. a, b, and ¢, d were pre- pared simultaneously, the solution of b containing a little more citric acid than that of a, and ¢ d more than either. The samples ¢, f, &, and hk were heated to about 100° C. lor fifteen minutes before being introdued into the com. bustion-tube, and the samples c, d, ¢, and f were the same. The results given under 2 are low, probably due to im- perfect oxidation. It will be seen that there is a deficiency of 0'02116 2nd 002088 respectively in the total of the duplicate analyses ¢ and d. The precaution was taken in one case of passing the products of the combustion over a red-hot layer of oxide of copper, to make sure that no hydrecarbon was distilled out by the gradually increasing heat, and so es- caped oxidation. The results in this case, however, differed in no material manner from those already obtained. We must therefore conclude that this deficiency must consist either of oxygen or nitrogen, or of a mixture of oth, I have already mentioned that there is no oxygen in the form of cuprous oxide present, so that it must, if present, be combined in some other form. The following synthetical experiments seemed to indicate that nitrogen was also an essential constituent. These experiments were conducted as follows :—Solu- tions were prepared of nitrate and of sulphate of copper; to these solutions were added respectively citric acid, tar- taric acid, and alcohol. All three of the solutions of the nitrate furnished the brittle deposit, while all three of the sulphate solutions gave a tough deposit of apparently or. dinary efectrotype ccpper. The amount of copper was determined in 10008 grms. of the precipitate from the sulphate solution containing alcohol, and found tobe 0'9gogI, * Zeitschrift fir Analytische Chemie, 1878, p. 127 This difference is probably due to impurities in the copper, which was prepared in the first place from the commercial sulphate, which contained lead and other impurities. During the ele@rolysis of the nitrate solutions contain- ng citric acid, a very strong odour of hydrocyanic acid was perceptible. If an insufficient amount of organic matter be added the precipitated copper obtained is not brittle, but it aevertheless contains carbon and hydrogen, and gives a otal result less than 100 per cent, This is due to admix- ure of ordinary copper. It is not possible to divide such 1 precipitate sufficiently finely to ensure perfe& oxidation. The amount of nitrogen present in the nitric-citric pre- tipitated copper, was determined by heating the finely sulverised sample in a vacuum and colle&ting the gases evolved. The produd@s thus obtained were hydrogen, carbonic acid, and nitrogen. Although in this case it was srobable that an excess of oxygen would be present, yet the analytical results showed the absence of that gas in any appreciable quantity. The volumes given are those of the dry gas at 0° C. and 760 m.m, 1 grm. heated In vacuo. Gas obtained .. .. .. 9°95 C.c. CO, absorbed by KOH... 472 Gas not CO, .. .. .. 5°23 Oxygen added... .. .. 777» 13°00 ,, Volume after explosion... 744 ,, Loss—Water .. .. .. 556 ,, No CO, formed: Hydro- gen ov ov ou. .. 3X Residue : Nitrogen., .. 152 These residues, treated with moist phosphorus to absorb *oxygen, and then with KOH, did not change, proving the absence of oxygen. The circumstances of formation were such as to pre- clude the existence of hydrogen, therefore these resi- dues must be nitrogen, The percentage results in the foregoing three cases are respectively for nitrogen—o-191, 0'221, 0199 ; and in the two last for carbon—o'7g2, 0736. The ratio of 8 seing 3'6 and 3°7. One sample of the produ&, made with tartaric acid, weighing 2 grms., was also analysed for nitrogen, and t c.c. of dry nitrogen at 0° C. and 760 m.m. obtained. It s difficult, when working on such small quantities of gas, :0 obtain very accurate results, Some of the allotropic copper prepared from the che- nically pure acetate, according to M. Schutzenberger's lirections, and which therefore could not contain nitrogen, and also some prepared from an acetate of copper cone :aining nitrate of soda, were compared and analysed. The material thus obtained was apparently the same in soth cases, and differed considerably in some of its pro- perties from the nitric-citric acid solution precipitate, In appearance, brittleness, and composition there was no :ssential difference, but it was very unstable and liable to oxidise ; in fad, it was not possible to preserve it of con-

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