Determination of the Atomic Weight of Cadmium and the Preparation of Certain of Its Sub-CompoundsJones, Harry C. (Harry Clary)
Science
Determination of the Atomic Weight of Cadmium and the Preparation of Certain of Its Sub-Compounds
Jones, Harry C. (Harry Clary)
Atomic weights; Cadmium; Thesis (Ph. D.)
The weighing of the oxalate was made in the weighing glasses in which
it was dried. Two of these glasses had been previously tared against
each other, using the lighter as the tare and adding fragments of
glass to it until the difference in weight was a small fraction of
a milligram. The oxalate having been dried to constant weight, was
weighed. It was then poured as carefully and completely as possible
from the weighing glass into the crucible and the glass again weighed
against its tare. The difference in the two weights gave the amount of
oxalate. The glass and its tare were dried and reweighed to determine
if the few milligrams of oxalate adhering to the walls of the glass
had absorbed any moisture during the transfer of the oxalate. In one
experiment a slight difference was detected when a second drying and
weighing were made.
The weight of the cadmium oxalate as obtained from the balance was
corrected for the difference in specific gravity between the cadmium
oxalate and the weights.
The Results.
At. Wt. At. Wt. At. Wt. At. Wt.
Cd. Cd. Cd. Cd.
(O=16) (O=16) (O=15.96) (O=15.96)
(C=12.001) (C=12.003) (C=11.971) (C=11.973)
CdC₂O₄ CdO
I 1.53937 .98526 112.026 112.033 111.746 111.753
II 1.77483 1.13582 111.981 111.988 111.701 111.708
III 1.70211 1.08949 112.049 112.056 111.769 111.776
IV 1.70238 1.08967 112.051 112.058 111.771 111.778
V 1.74447 1.11651 112.019 112.026 111.739 111.746
------- ------- ------- -------
Mean, 112.025 112.032 111.745 111.752
Maximum, 112.051 112.058 111.771 111.778
Minimum, 111.981 111.988 111.701 111.708
Difference, .070 .070 .070 .070
The values assigned to carbon in the last two columns were found thus--
When O = 16, C = 12.001, when O = 15.96, C = 11.971.
” O = 16, C = 12.003, ” O = 15.96, C = 11.973.
Calculating the atomic weight directly from all the oxalate used and
oxide found it would give:
At. Wt. Cd. At. Wt. Cd. At. Wt. Cd. At. Wt. Cd.
(O = 16) (O = 16) (O = 15.96) (O = 15.96)
(C = 12.001) (C = 12.003) (C = 11.971) (C = 11.973)
112.025. 112.032. 111.745. 111.752.
There seems about equal evidence for the two values assigned to carbon
when oxygen = 16. The value of cadmium as given by this method is
therefore 112.025 or 112.032.
As will be seen at a glance this figure agrees much more closely with
that of Lenssen than with that of Partridge.
Lenssen Partridge My work
112.043. 111.816. 112.025 or
112.032.
Public-domain text, read in full here on John Shaqi.
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