Kopp, Ober das Bildnis Alexanders d.
Text by Valckenaer, 1739, Schafer, 1822; Kopp, De Ammonii.
Kopp contributed the general theoretical part, Kolbe the organic, and Buff and Zamminer the physico-chemical.
Kopp, begun in 1842, on the molecular volumes, the volume occupied by one gramme molecular weight of a substance, of liquids measured at their boiling-point under atmospheric pressure, brought to light a series of additive relations which, in the case of carbon compounds, render it possible to predict, in some measure, the cornposition of the substance.
By the indirect method Kopp derived the following atomic volumes: C. 0.
Recent researches have shown that the law originally proposed by Kopp - " That the specific volume of a liquid compound (molecular volume) at its boiling-point is equal to the sum of the specific volumes of its constituents (atomic volumes), and that every element has a definite atomic value in its compounds " - is by no means exact, for isomers have different specific volumes, and the volume for an increment of CH 2 in different homologous series is by no means constant; for example, the difference among the esters of the fatty acids is about 57, whereas for the aliphatic aldehydes it is 49.
Theoretical considerations as to how far Kopp was justified in choosing the boiling-points under atmospheric pressure as being comparable states for different substances now claim our attention.
The results of Berzelius were greatly extended by Hermann Kopp, who recognized that carbon, boron and silicon were exceptions to the law.
Kopp systematized the earlier observations, and, having made many others, he was able to show that the molecular heat was an additive property, i.e.
Hoefer, Histoire de la chimie (2nd ed., 1866-1869); Hermann Kopp, Geschichte der Chemie (1869), Entwickelung der Chemie in d.
Kopp. The following are his most important separate publications, many of which were translated into English and French almost as soon as they appeared: Anleitung zur Analyse der organischen Korper (1837); Die Chemie in ihrer Anwendung auf Agrikultur and Physiologic (1840); Die Thier-Chemie oder die organische Chemie in ihrer Anwendung auf Physiologie and Pathologie (1842); Handbuch der organischen Chemie mit Rficksicht auf Pharmazie (1843); Chemische Briefe (1844); Chemische Untersuchungen fiber das Fleisch and seine Zubereitung zum Nahrungsmittel (1847); Die Grundsdtze der Agrikultur-Chemie (1855); Ober Theorie and Praxis in der Landwirthschaft (1856); Naturwissenschaftliche Briefe fiber die moderne Landwirthschaft (1859).
HERMANN FRANZ MORITZ KOPP (1817-1892), German chemist, was born on the 30th of October 1817 at Hanau, where his father, Johann Heinrich Kopp (1777-1858), a physician, was professor of chemistry, physics and natural history at the Lyceum.
Kopp devoted himself especially to physico-chemical inquiries, and in the history of chemical theory his name is associated with several of the most important correlations of the physical properties of substances with their chemical constitution.
In addition to these and other laborious researches, Kopp was a prolific writer.
He must not be confused with Emil Kopp (1817-1875), who, born at Warselnheim, Alsace, became in 1847 professor of toxicology and chemistry at the Ecole superieure de Pharmacie at Strasburg, in 1849 professor of physics and chemistry at Lausanne, in 1852 chemist to a Turkey-red factory near Manchester, in 1868 professor of technology at Turin, and finally, in 1871, professor of technical chemistry at the Polytechnic of Zurich, where he died in 1875.
The stereometer of Say, which was greatly improved by Regnault and further modified by Kopp, permits an accurate determination of the volume of a given mass of any such substance.
Kopp (1826), and in full by C. E.
Kopp (Urkunden zur Geschichte d.
Kopp) to a colourless oil; and boils at 223° (H.
Kopp in 1844 and B.