Qualitative chemical analysis / by C. Remigius Fresnius.

  • Fresenius, C. Remigius, 1818-1897. Anleitung zur qualitativen chemischen Analyse. English
Date:
1872
Catalogue details

Licence: Public Domain Mark

Credit: Qualitative chemical analysis / by C. Remigius Fresnius. Source: Wellcome Collection.

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    OPERATION.?. §§ 1, 2.] The study of qualitative analysis is most properly divided into four principal parts—viz., 1. Chemical operations. 2. Reagents and their uses. 3. ReACTIONS, OR DEPORTMENT OF THE VARIOUS BODIES WITH REAGENTS. 4. SYSTEMATIC COURSE OF QUALITATIVE ANALYSIS. It will now be readily understood that the pursuit of Chemical analysis requires practical skill and ability as well as theoretical know- ledge; and that, consequently, a mere speculative study of that Science can be as little expected to lead to suecess as purely empirical experi- ments. To attain the desired end, tlieory and practice must be combined. SECTION I. OPERATIONS. § 1. The operations of analytical chemistry are essentially the same as tliose of synthetical chemistry, though modified to a certain extent to adapt thern to the different object in view, and to the small quantities operated upon in analytical investigations. The following are the principal operations in qualitative analysis. § 2. 1. Solution. The term solution, in its widest sense, denotes the perfect union of a body, no matter whether gaseous, liquid, or solid, with a fluid, resulting in a homogeneous liquid. However, where the substance dissolved is gaseous, the term absorption is more properly made use of; and the solution of one fluid in another is more generally called a mixture. The application of the term solution, in its usual and more restricted sense, is confined to the perfect union of a solid body with a fluid. A solution is the more readily effected the more minutely the body to be dissolved is divided. The fluid by means of which the solution is effected, is called the solvent. We call the solution Chemical, where the solvent enters into Chemical combination with the substance dissolved; simple, where no definite combination takes place. In a simple solution the dissolved body exists in the free state, and retains all its original properties, except tliose dependent on its form and cohesion; it separates unaltered when the solvent is withdrawn. Com- mon salt dissolved in water is a familiär instance of a simple solution. The salt in this case imparts its peculiar taste to the fluid. On evapo- rating the water, the salt is left behind in its original form. A simple solution is called saturatcd if the solvent has received as much as it can retain of the dissolved substance. But as fluids dissolve generally larger quantities of a substance the higher their temperature, the term satu- rated, as applied to simple Solutions, is only relative, and refers invariably
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