Chemists, Among Other Things

Delville, Edouard Chimiste departageur Ecole Normale des Sciences, Ghent 1864 Teacher at the Athenee Royal, Toumai 

Depuydt, Julien (1842-1919) Chimiste departageur Mechanical engineer, Ecole des Mines, Mons 1864 Chemist at the Societe Commerciale, Industrie et Maritime, Antwerp 

Francken, Victor (1842-1892) Chimiste departageur Engineer, Ecole des Mines, Department Arts et Manufactures, Liege 1862 Teaching assistant in the course on the analysis of industrial products. University of Liege 

Gaillard, M. Chimiste prive Chemist at a sugar factory in Tienen 

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Improving the duty meant using fuel more efficiently, but to rationalize that easy truth was the work of more than a century. Theoretically, it depended, among other things, on the recognition in 1758 by Adam Black—Watt s mentor at Glasgow—of a distinction between heat and temperature, and the recognition by nineteenth-centuiy chemists of an absolute zero of temperature. On the practical side... 

Example 14.4 shows, among other things, how effectively a buffer soaks up H+ or OH ions. That can be important Suppose you are carrying out a reaction whose rate is first-order in H+. If the pH increases from 5 to 7, perhaps by the absorption of traces of ammonia from the air, the rate will decrease by a factor of 100. A reaction that should have been complete in three hours will still be going on when you come back ten days later Small wonder that chemists frequently work with buffered solutions to avoid disasters of that type. 

Walter Kohn has been a great help to many scientists over many years, an expert consultant and helpmate and a fine, unobtrusive, even-handed host of good meetings in lovely places. We thank him. In recent years I have discussed with him (among other things), circulant orbitals, the monotonic density theorem, and the information theory point of view on what constitutes an atom in a molecule, the latter during a stolen few minutes in a Stockholm hotel in December of 1999 [6]. Walter may or may not like chemistry [7], and he claims not to have studied chemistry in the university. But what does one call a great teacher of chemical principles I would say, CHEMIST, full caps. 

The formula, which contains (among other things) an aromatic and an oligocyclic moiety, is so complicated that a chemist who is not an expert in nomenclature cannot determine the chemical name. The structural formula is C23H25O7 ... 

Geologists brave the awesome fury of volcanoes and earthquakes oceanographers plumb the hidden depths of the world. What do chemists do Well, they make paint, among other things. 

There are a number of commonly used reactions of this type and many are named after the chemists who discovered them. They differ, among other things, in the exact nature of the metallic component. One of the first to be developed extensively was the Stille coupling, which specifically involves the coupling of an arylstannane with an aryl halide or triflate under the action of palladium catalysis (Scheme 10.19). 

Our initial definition of acids and bases in Section 3.3 involved the formation of hydronium ions (for acids) or hydroxide ions (for bases). This definition is attributed to Svante Arrhenius, but it can be expanded to include nonaqueous solutions, among other things. Formulated independently in 1923 by two chemists, Johannes Bronsted in Denmark and Thomas Lowry in England, the Bronsted-Lowry definition does just that. According to this definition, a Bronsted-Lowry acid is a proton (H+) donor, and a base is a proton acceptor. 

Based upon many years of empirical evidence, chemists have developed a series of guiding principles that give us insight into chemical reactivity. Among other things, these principles allow us to quickly decide the shape of a reaction coordinate diagram, predict a product ratio, and determine how the stability of a molecule would affect its reactivity. Here we introduce these time honored tools of the physical organic chemist. 

Let us remember Coulson (1960, 174), again "Chemistry itself operates at a particular level of depth. At that depth certain concepts have significance and—if the word may be allowed—reality. To go deeper than this is to be led to physics and elaborate calculation. To go less deep is to be in a field akin to biology." Coulson did his utmost to convince chemists—and, perhaps, physicists— that in quantum chemistry, the role of theory was not something static, and it had a lot to do, among other things, with the demands of the community, of its decisions concerning the "appropriate depth" at which quantum chemistry will operate. 

FIGURE 20.15 Svante Arrhenius (1859-1927), a Swedish chemist who— among other things—came up with a simple relationship between the rate constant and the absolute temperature. 

To achieve these goals will require, among many other things, a dramatic increase in the interactions among chemists, engineers, biologists, and physicists. 

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