A systematic handbook of volumetric analysis, or, The quantitative estimation of chemical substances by measure, applied to liquids, solids, and gases / by Francis Sutton.

Date:
1886
Catalogue details

Licence: Public Domain Mark

Credit: A systematic handbook of volumetric analysis, or, The quantitative estimation of chemical substances by measure, applied to liquids, solids, and gases / by Francis Sutton. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    THE INSTRUMENTS AND APPARATUS. THE BALANCE. § 2. Strictly speaking, it is necessary to have two balances in order to carry out the volumetric system completely ; one to carry about a kilogram in each pan, and turn when loaded with about five milligrams. This instrument is used for graduating flasks, or for testing them, and for weighing large amounts of pure reagents for standard solutions. The second balance should be light and delicate, and to carry about fifty grams, and turn easily and quickly when loaded with one or two-tenths of a milligram. This instrument serves for weighing small quantities of substances to be tested, many of which are hygroscopic, and need to be weighed quickly and with great accuracy ; it also serves for testing the accuracy of pipettes and burettes. For all technical purposes, however, a moderate sized balance of medium delicacy is quite sufficient, especially if rather large quantities of substances are weighed and brought into solution— then further subdivided by means of measuring flasks and pipettes. The operator also requires, besides the balance and the graduated instruments, a few beakers, porcelain basins, flasks, funnels, stirring- rods, etc., as in gravimetric analysis; above all he must be practically familiar with proper methods of filtration, washing of precipitates, and the application of heat. VOLUMETRIC ANALYSIS WITHOUT WEIG-HTS. § 3. This is more a matter of curiosity than of value; but, nevertheless, one can imagine circumstances in which it might be useful. In carrying it out, it is necessary only to have (1) a correct balance, (2) a pure specimen of substance to use as a weight, (3) an accurate burette filled with the appropriate solution. It is not necessary that the strength of this should be known; but the state of concentration should be such as to permit the necessary reaction to occur under the most favourable circumstances. If a perfectly pure specimen of substance, say calcic carbonate, be put into one scale of the balance, and be counterpoised with an impure specimen of the same substance, and both titrated with the same acid, and the number of c.c. used for the pure substance bo called 100, the number of c.c. used for the impure substance will correspond to the percentage of pure calcic carbonate in the specimen examined. The application of the process is, of course, limited to the use of such substances as arc to be had pure, and whoso weight is not variable by exposure; but where even a pure substance of one kind