Chemical Affinity

Also found in: Dictionary, Thesaurus, Medical, Legal, Wikipedia.

chemical affinity

[′kem·i·kəl ə′fin·əd·ē]
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Chemical Affinity


a term used to describe the capacity of a substance to react with another substance or to describe the degree of resistance of the resulting compound to decompose into the initial components.

At various times, attempts were made to evaluate chemical affinity in terms of various reaction parameters. In the mid-19th century, the quantity of heat released in the course of a reaction came to be used as the measure of affinity. However, the existence of spontaneous endothermic reactions indicated the restricted applicability of this approach. In 1883, J. van’t Hoff proved, on the basis of the second law of thermodynamics, that the course of a spontaneous reaction is determined by the reaction’s maximum useful work rather than its thermal effect. At the same time, he derived an equation that quantitatively expressed the maximum useful work as a function of the concentrations of the substances taking part in the reaction and the direction of the reaction as a function of the ratios of these concentrations.

At present, attention is being focused not on the maximum work but rather on changes in the Gibbs free energy ΔG for reactions proceeding at constant temperature and pressure or in the Helmholtz free energy ΔA for reactions proceeding at constant temperature and volume. In this case, the concept of chemical affinity is no longer applicable.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
From the EDS results, it was observed that Pd, Cu, and Ni metals with high chemical affinity were mutually diffused during the Cu-reflow heat treatment.
From this study, it is suggested that chemical affinity between phenolic resins and organically modified MMT is a very important factor in preparing NR-LSN as well as ER-LSN.
Berthollet's ideas on chemical affinity, equilibrium, and the effects of mass changes on chemical reactions were presented in his two books printed at the beginning of the 19th century.
These polymers show a certain chemical affinity for the original molecule and can be used to fabricate sensors.
Silicone elastomers inherently have a high degree of surface tack and a tendency for blocking (sticking to themselves by virtue of chemical affinity), which may cause problems in applications in which they come in contact with each other or other surfaces.
Manganese, having comparatively weak chemical affinity to interstitial elements, can not, in contrast to lanthanum and other rare-earth metals, refine chrome matrix of these impurities.
"Many EPDM materials have excellent physical properties but their chemical affinity for metal makes them difficult to process," states Bill Burnham, Axel technical service representative.
Many EPDM (ethylene-propylene-diene-monomer) materials have desirable physical properties, but their chemical affinity for metal makes them difficult to process.
Prolinx released SPM-HC High-Capacity Beads and Protein Releasing Reagent as part of its Versalinx Chemical Affinity Tools ...

Full browser ?