|A human chemical affinity cartoon. |
The atoms of a given element, for example, may have a greater affinity for the atoms of one element than for another, e.g. hydrogen H has a great affinity for chlorine Cl, with which it easily and rapidly combines to form hydrogen chloride, but has little or no affinity for argon. The affinity between an enzyme and a substrate molecule is another example.
Human chemical affinity
See main: Human chemical affinity; Human elective affinityThe model of chemical affinity extrapolated up to the level of reaction occurring between human molecules (people) is called "human chemical affinity" or "human elective affinity" as German polymath Johann Goethe explained the phenomenon in his famous 1809 Elective Affinities. In 1910, American historian Henry Adams, in his A Letter to American Teachers of History, cogently connected the notion of chemical affinity, within the context of thermodynamics, to the "will" of a person: 
“If thought is capable of being classified with electricity, or will with chemical affinity, as a mode of motion, it seems necessary to fall at once under the second law of thermodynamics. Of all possible theories, this is likely to prove the most fatal to professors of history.”
In 1948, American author Thomas Dreier correctly explained human attraction as such:
“The mystery of human attraction is really no mystery; it is a matter of chemical affinity, as powerful as it often is seemingly incomprehensible.”
The following are example quotes:
“Chemical affinity is that force in substance which brings and holds together what under general conditions are considered the indivisible elements of matter or atoms. In most cases such combinations are made at the expense of others previously existing: that is, there is dissolution of some existing combination, and a formation of a new one out of the atoms that had existed in the old. All chemical changes taking place in nature are the result of chemical affinity.”— Henry Bray (1910), The Living Universe (pg. 368)
● Affinity table
● Free energy table
● Elective affinity
1. Clark, John O.E. (2004). The Essential Dictionary of Science. New York: Barnes & Noble Books.
2. Dreier, Thomas. (1948). We Human Chemicals: the Knack of Getting Along with Everybody (pg. 66-67). Updegraff Press.
3. (a) Adams, Henry. (1910). A Letter to American Teachers of History (pg. 102). Washington; in The Degradation of the Democratic Dogma (pg.195). MacMillan, 1919.
(b) Matthias, Ruth. (2011). “Entropy, Economics, and Policy”, in: Thermodynamics and the Destruction of Resources (ch. 16, pgs. 402-28; quote, pg. 402). Cambridge University Press.
4. Jarape. (year), “Chemical Affinity”, in: Chem 13 News, Mon.
● Kane, Robert and Draper, John W. (1843). Elements of Chemistry (ch. VI: Of Chemical Affinity: and its relations to Heat, to Light, and to Cohesion, pgs. 157-). Harper & Brothers.
● Korevaar, A. (1921). “On Chemical Affinity” (abstract), J. Phys. Chem. 25(4): 304-10.
● Hudleston, Lawson J. (1928). Chemical Affinity. Longmans, Green
● Holmes, Frederic L. (1962). “From Elective Affinities to Chemical Equilibria: Berthollet’s Law of Mass Action”, Chymica, 8: 105:45.
● Chemical affinity – Wikipedia.
● Chemical affinity – Britannica, 1911.