. Carnegie Institution of Washington publication. OF ZINC, CADMIUM, LEAD, COPPER, AND LITHIUM 67 then, a gram-atom of lead dissolved in a hundred gram-atoms of mercury must absorb about 540 joules or 130 calories on infinite dilution; and of this amount about two-thirds is absorbed when the amalgam is diluted with twice its bulk of mercury. With these figures are repeated also, in conveniently accessible form, the other results obtained in this monograph by the application of the equation of Helmholtz. TABLE 21.—Heat of Dilution of Amalgams Calculated from the Electrical Measurements. Metal. D
. Carnegie Institution of Washington publication. OF ZINC, CADMIUM, LEAD, COPPER, AND LITHIUM 67 then, a gram-atom of lead dissolved in a hundred gram-atoms of mercury must absorb about 540 joules or 130 calories on infinite dilution; and of this amount about two-thirds is absorbed when the amalgam is diluted with twice its bulk of mercury. With these figures are repeated also, in conveniently accessible form, the other results obtained in this monograph by the application of the equation of Helmholtz. TABLE 21.—Heat of Dilution of Amalgams Calculated from the Electrical Measurements. Metal. Designation Range of dilution Heat of dilution of solid per gram-atom metal . Joules. Gram calories. Thallium Cl-C2 i . 84 to o . 53 + 427 + Do C2-C3 o . 53 o . 23 + IO9 + Indium .... Ei-E2 + 677 + Do .... Gi-G2 — 4 — I . Tin Ji-j2 - 69 - Zinc MI-MS — 247 - 59-0 Cadmium. R&Fi-s - 6 — Lead PI-P2 I . 02 0 . 40 -338 - Do P2-P4 — 117 - Do Qi-Q3 — 77 - Because the heat capacity of the reacting system is essentially constant, these values are independent of the temperature, as far as our measure- ments were concerned. Their chief uncertainty depends upon the diffi- culty of measuring exactly the temperature coefficients of small electro- motive forces : but they are accurate enough to serve as a fairly close guide to the behavior of the respective amalgams. They are hardly close enough to serve as the basis for a search after an exact mathematical law governing the change of thermal effect with increasing dilution, although such a search would be an interesting aspect of yet more precise measure- ments. 'Cv. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Carnegie Institution of Wash
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