Chemical affinity, attraction

For an analysis of the language of "matter," substance," and "body" in natural philosophy, chemistry, and natural history, see Mi Gyung Kim, "Layers of Chemical Language," 7180. Kim similarly analyzes the terms "attraction," "affinity," and "relationship" and "aggregation," "composition," and "constitution."... 

The binding constants of selected ligands of class A were determined to obtain their ranking with respect to their affinity to the protein and to select a chemically attractive compound for further detailed characterization of its mode of binding. The compound HUB093 was chosen by medicinal chemists as interesting. Using uniformly 13C-labeled... 

The attraction of coloring matter by charcoal is denominated mechanical, while the attraction of sulphuric acid by baryta is classed with chemical effects. But animal charcoal does not only attract coloring matter it aho decomposes metallic salts, and fixes their base by that same power of retention., Now it is known that chemical combinations and decompositions are produced by differences in intensity of one only chemical attractive force eollod affinity. It is evident that the same force is inherent in animal charcoal. This view is corroborated by the fact thot animal charcoal absorbs different compounds in different bnt determined quantities. Niepce has shown that iodine and chlorine gas ore condensed by the Inked portion of printed paper, while the white portion of the paper dees not retain any of the gases. Charcoal absorbs heat and light most readily.. It.Condenses... 

The attention of many chemists from about this time was devoted to ascertaining the laws and generalizations of chemical attraction or affinity. The first serious attempt to systematize the relative affinities between substances was that of Etienne Francois Geoffroy (1672-1721), Professor of Chemistry at the Jardin du Roi from 1712 to 1731. He presented a memoir to the Academy of Sciences at Paris in 1718, entitled Table of the different Connections rapports ) observed in Chemistry between different Substances. In this he lays down as his fundamental law Whenever two substances having some tendency to combine with each other are found combined and there enters a third which has more affinity with one of the two, it unites with that one, setting the other free. ... 

Stahls view of the cause of chemical reactions had a very respectable antiquity. He relied on the doctrine of affinities, which traditionally meant the chemical attraction of like for like. It was only later that affinity came to mean the chemical attraction of opposites, for example, of acids for alkalis or, in the nineteenth century, of electronegative for electropositive substances (see Chapter 7). Metals could form alloys, often regarded by chemists as mixts or compounds, by virtue of their shared metallic character. Metals could be dissolved in acids because acids and metals had something in common, some shared principle. That was far from apparent, and it was up to chemists to demonstrate that it was true. Chemists would use the methods and tools of analysis to identify the constituents of mixts. 

Newtonian attraction could not provide a comprehensive systematics of chemical operations. Fourcroy s fourth law was concerned with affinity among several bodies, or complicated affinity, which could not assume the mathematical form of attraction. Affinity, as an active metaphor, possessed greater heuristic and organizing power than attraction, in part because of its less-than-precise meaning. Chemical combination usually yielded a compound with a completely new set of properties, as his eighth law stipulated, not simply the properties of its principles. Seemingly innocuous, this law reveals mostly clearly Fourcroy s deep-seated conviction that affinity, not the principles, determined the composition of bodies. 

Affinity and heat constituted the most theoretical part of chemistry. In line with the pedagogical purpose of the new school, which was to train the students in basic methods or the art of teaching, Berthollet assumed an elementary knowledge of chemistry on the part of the students and sought to provide exact notions of theories which serve as the basis of all the development of teaching and lead their spirit to general ideas. These theories for chemistry comprised affinities and the principle of heat or caloric. Chemical attraction was the principle of all chemical phenomena or the immediate cause of dissolution, combination, and composition. If the molecules of bodies obeyed only this... 

In the second lecture,Berthollet took up the real action of affinities, and the causes that can modify their effects, or the anomalies of chemical attraction. He was well aware of the pre-revolutionary dis-... 

Berthollet s conception of caloric as a principle subject to chemical attraction or a fluid that interacted with other chemical bodies through its affinities encapsulated the Arsenal Group s vision of integrating heat as a part of chemical constitution. He shared this conception with the other authors of the Chemical Revolution. 

After a two-page discussion of the nature of chemical attraction, Berthollet moved on to the notion of chemical combination and constitution. The immediate effect of chemical affinity was always a combination, although it was modified by the quantity of the bodies under consideration. Berthollet did not abandon the sense of specificity assigned to each affinity ... 

Solid-phase extraction (SPE) is a procedure in which an analyte, contained in a liquid phase, comes in contact with a solid phase (sorbent particles in a column or disk) and is selectively attracted to the surface of that solid phase. All other materials not adsorbed by chemical attraction or affinity remain in the liquid phase and go to waste. A wash solution is then usually passed through the sorbent bed to remove any loosely adsorbed contaminants from the sample matrix, yet retain the analyte of interest on the solid phase. Einally, an eluting solvent (usually an organic solvent such as methanol or acetonitrile that may be modified with acid or base) is added to the sorbent bed. This solvent disrupts the attraction between the analyte and solid phase that cause desorption,... 

The force of chemical attraction, or affinity, is unequal in the case of different substances. Thus, the affinity between potassium and oxygen is more powerful than between gold and oxygen. 

It is obvious that, since chemical attraction operates between the particles of di rent bodies, and only when they are at infinitely small distances, the cohesion between the particles of two solid bodies respectively must impede chemical action by preventing the sufficiently close approximation and intermixture of the particles which have affinity for each other. Hence the solid form is most unfavourable to chemical action, although, in rare cases, the power of affinity is sufficient to overcome the obstacle. Thus, phosphorus and iodine, both in the solid form, act powerfully on one another. 

Every infinitely small phase of the mass of an element contains an infinitely small part of the chemical attractive force or affinity. If a neutral compound is composed from two elements then, provided both elements are in the same state in the two cases, the ratio of the masses is the same in the first case as in the second. ... 

Turkey red dyeing was introduced by John Wilson of Ainsworth in 1762, and bleaching was generally introduced into the Manchester district in 1763. Henry adopted the chemical theory the unequal powers of wool, silk, linen, and cotton for taking up and fixing dyes he regarded as due to different chemical attractions. Mordants have affinities for the fabric and the colour and... 

The dawn of the nineteenth century saw a drastic shift from the dominance of French chemistry to first English-, and, later, German-influenced chemistry. Lavoisier s dualistic views of chemical composition and his explanation of combustion and acidity were landmarks but hardly made chemistry an exact science. Chemistry remained in the nineteenth century basically qualitative in its nature. Despite the Newtonian dream of quantifying the forces of attraction between chemical substances and compiling a table of chemical affinity, no quantitative generalization emerged. It was Dalton s chemical atomic theory and the laws of chemical combination explained by it that made chemistry an exact science. 

Collectors ndFrothers. Collectors play a critical role ia flotation (41). These are heteropolar organic molecules characterized by a polar functional group that has a high affinity for the desired mineral, and a hydrocarbon group, usually a simple 2—18 carbon atom hydrocarbon chain, that imparts hydrophobicity to the minerals surface after the molecule has adsorbed. Most collectors are weak acids or bases or their salts, and are either ionic or neutral. The mode of iateraction between the functional group and the mineral surface may iavolve a chemical reaction, for example, chemisorption, or a physical iateraction such as electrostatic attraction. 

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