vacuum. If Cl = 35.42 (Turner) the value follows. (Phil. Trans., 123, 1833, 536.) F. PENNY: 107.97 (0 = 16). Penny made six experiments on the conversion of silver into nitrate. The silver was dissolved in cold nitric acid, the solution evaporated, and the nitrate fused all in one flask and with precautions against loss by spiriting. He found 100 Ag=157.441 nitrate; extreme difference, 0.028. In five experiments the nitrate from the preceding determinations was converted into chloride, by means of chlorhydric acid, in the same flask, dried, fused, and weighed. Penny could detect no decomposition in fusion. He found 100 Ag 132.8372 chloride; extreme difference, 0.01. In two experiments silver was dissolved in nitric acid, precipitated with chlorhydric acid, evaporated and fused, giving 132.830 and 132.838. The mean of all seven experiments is 132.836. Penny takes 132.837. From the relations of the chlorides, chlorates, and nitrates of potassium and sodium, Penny had determined the difference between the atomic weights of a chloride and a nitrate at 26.565. This gives the molecular weight of argentic chloride at 143.424 and Ag 107.97. The silver used, as well as the water and the acids, were carefully tested for impurities and a minute amount of solid residue in the twice distilled water and in the acids was allowed for. The weighings were all reduced to vacuum. (Phil. Trans., 129, 1839, 27.) = = 16); 675 (0= 100). C. MARIGNAC: 108 (0 Silver was dissolved in nitric acid and precipitated with chlorhydric acid. One experiment, reduced to vacuum, gave 100 silver 132.74 chloride, which Marignac considered confirmatory of Berzelius' value, 132.75. He therefore adopted the latter number. 100 potassic chloride were found to produce 192.26 argentic chloride, in two experiments, the difference between which was 0.01. By analysis, by means of heat, of potassic chlorate, Marignac had found the molecular weight of the chloride 932.14, these relations give the molecular weight of argentic chloride at 1792.13 and the atomic weight of silver at 1350. The potassic chloride was prepared by heating the chlorate and cooling the resulting chloride over sulphuric acid. (Liebig's Ann., 44, 1842, 23.) = C. MARIGNAC: 107.922 (0 = 16); 674.505 (O=100). Marignac redetermined the relation between silver and potassic chloride by Pelouze's method. He found 100 Ag 69.062 KCl in six experiments, the extreme difference between which was 0.018. In five experiments he found 100 KCl = 192.348 Ag; extreme difference 0.04. He also redetermined the composition of argentic chloride. The silver was dissolved in a long-necked flask and the fumes passed into a second flask containing water. Solution being effected, the water from the second flask was added to the contents of the first, and the whole precipitated with HCl. The chloride was washed, dried, melted and weighed in the same flask. The result was 100 Ag: 132.84 chloride; extreme difference 0.019. Combination of these data with Marignac's old value for the molecular weight of KCl, 932.14, gives Ag = 1349.01. All weighings reduced to vacuum. Berzelius revised the result by throwing out one experiment and by rejecting the correction for vacuum. He thus got Ag=1349.66. (Berzelius' Jahresbericht, 24, 58; 25, 31; Bibl. Univ. de Genève, 46, 1842, 350.) = In opposition to Prout's hypothesis, Marignac cites his analyses of argentic acetate, in which the escaping gases were forced to pass over porous silver. They gave in three experiments 64.664 silver from 100 acetate; extreme difference 0.005. If C-75, this gives Ag=1349.6. He also found 100 Ag= 157.455 nitrate. [If N = 87.5, this gives Ag 1348.88.] He also found 100 Ag= 49.556 ammonium chloride. (Liebig's Ann., 59, 284; Bibl. Univ. de Genève, 1846.) = LIEBIG and REDTENBACHER; STRECKER: 107.903 (0 = 16); 674.395 (0 = 100). Strecker recalculated Liebig and Redtenbacher's analyses of argentic acetate, tartrate, racemate and malate by the method of least squares, and from the difference in the atomic composition of these salts. He obtained for Ag the value 1348.79. Vide Carbon. (Liebig's Ann., 59, 1846, 280.) E. J. MAUMENÉ: 108.026 (0 = 16); 675.16 (0= 100). In four experiments argentic oxalate was mixed with sand in a flask and decomposed by heat in a current of air. The products of decomposition were passed over cupric oxide, and through drying tubes and potash tubes. In five experiments the acetate was treated in the same way, but not mixed with sand. The mean result was Ag = 1350.32; extreme difference 0.77. Maumené found it very difficult to purify the oxalate, which showed traces of nitric acid after 100 washings. (Annal. de Chim. et de Phys., (3,) 18, 1846, 41.) J. S. STAS: 107.93 (O = 16). Thirteen syntheses of argentic iodide, performed by bringing hydroiodic acid in contact with argentic sulphate or nitrate, gave 100 Ag= 117.5343 iodine. Three analyses of argentic iodate, performed by decomposition by heat in a current of nitrogen or by reduction of the salt, while in suspension, by a current of sulphurous_anhydride, gave AgI= 234.779. Hence Ag=107.928. Four syntheses of the bromide, performed by bringing hydrobromic acid in contact with argentic sulphate, gave 100 Ag= 74.0805 Br. Two analyses of argentic bromate, by reduction while in suspension with sulphurous anhydride, gave Ag Br= 187.87. Hence, Ag= 107.921. 107.921. Seven syntheses of argentic chloride, three of them by combustion of silver in chlorine, three by precipitation with HCl, and one by precipitation with ammonium chloride, gave 100 Ag= 32.8445 Cl. Stas adopts the number 32.85 on the supposition that no excess of chlorine was possible. The chloride was fused. Two analyses of the chlorate, accomplished by heat or by evaporation with chlorhydric acid, gave Ag Cl = 143.395. Hence Ag 107.937. Five syntheses of the sulphide, performed by heating silver in a current of sulphur vapor, or of hydrogen sulphide, gave 100 Ag=114.8522 argentic sulphide. Six analyses of the sulphate by reduction in a current of hydrogen, showed that 100 sulphate contained 69.203 silver, hence Ag=107.920, [107.926? vide Sulphur.] From analysis of potassium chlorate, Stas had determined the molecular weight of KCl at 74.59. By twenty-four determinations he found 100 Ag= 69.103 KCl, hence Ag=107.943. The silver was prepared either by Levol's method or by decomposing an ammoniacal solution of argentic nitrate with a mixture of ammonium sulphite and a copper salt. The metal was heated to the boiling point until the sodium line disappeared and the metallic fumes were a pale blue. To test its purity, it was compared with distilled silver. See Stas's determinations of Cl, Br, I, S, = and K. All weighings reduced to vacuum. (Stas, Untersuch. über Chem. Prop., Leipzig, 1867.) SODIUM. The specific heat of sodium has been determined by Regnault and indicates an atomic weight of about 23. (GmelinKraut, l. c.) H. DAVY; F. H. WOLLASTON: 23.28 (0= 16); 145.5 (0 = 100). Davy found that 134 Cl combine with 88 Na to form sodium chloride. If Cl=441, the value follows. (Phil. Trans., 104, 1814, 20.) J. J. BERZELIUS: 23.164 (0 = 16). Berzelius found that 100 Na Cl= 244.6 Ag Cl. [If Ag Cl=143.387, (Stas,) the value follows.] (Poggend. Ann., 8, 1826, 189.) F. PENNY: 23.046 (0 = 16). Penny made four experiments on the conversion of the chlorate into the chloride by means of HCl. A known weight of the salt was dissolved in a flask in the acid and evaporated, dried and weighed without removal. The sodium chloride was not fused. The mean result was that 100 chlorate equals 54.930 chloride; extreme difference, 0.02. This relation gives the molecular weight of the chloride at 58.5. Penny had found the atomic weight of Cl = 35.454; hence the value for Na. [If Cl=35.457 (Stas,) Na= 23.043. Stas himself found 23.043.] The sodium chlorate was prepared by precipitating potassium chlorate with sodium bitartrate, and purifying the sodium chlorate by recrystallization. The weighings are for vacuum. (Phil. Trans., 129, 1839, 25.) J. PELOUZE: 22.97 (O= 16); 143.59 (O=100). A known weight of perfectly pure silver was dissolved in nitric acid, and brought in contact with a known and slightly excessive weight of sodium chloride, and the excess titrated with decimal silver solution. The mean result of three experiments was that 100 Ag=51.141 Na Cl; extreme difference, 0.033. The value follows for Ag= 1349.01; Cl=443.2. The sodium chloride was prepared either from sodium sulphate and barium chloride, or from sodium carbonate and chlorhydric acid, or from a very pure rock salt. It was repeatedly recrystallized and was dried at 200° or melted. (Paris Comptes Rend., 20, 1845, 1047.) J. DUMAS: 23.011 (0 = 16). Determined from the mean of seven experiments on the titration of sodium chloride with argentic nitrate; extreme difference, 0.09. Ag=108; Cl=35.5 [Dumas gives the mean as 23.014 instead of 23.0114.] For five experiments Na Cl recrystallized ten times and melted was employed. For two experiments (giving an average of 23.036) the residue from the incineration of the acetate was used to prepare Na Cl, which was recrystallized four times and melted. (Annal. de Chim. et de Phys., (3,) 55, 1859, 129.) J. S. STAS: 23.043 (0.= 16). = = According to the mean of 10 determinations 100 Ag= 54.2078 Na Cl; extreme difference 0.0033. The sodium chloride was found to contain a minute quantity of silicic acid which reduces the result from Na 23.049 to 23.045 for Ag=107.93; Cl=35.457. According to the mean of five determinations 100 Na Cl 145.4526 sodium nitrate; extreme difference 0.025. If N = 14.044 this gives Na= 23.045. The lowest determination gives Na = 23.042. The sodium chloride was purified by recrystallization and in part by conversion into sodium chloroplatinate. The weighings are for vacuum. (Stas, Untersuch. über Chem. Prop., Leipzig, 1867.) STRONTIUM. Regnault determined the specific heat of strontium chloride. It corresponds to an atomic weight of about 87.5. (Gmelin-Kraut, l. c.) |