Chemical Affinity

Chemical Affinity is the name given to the tendency to combine with one another which is exhibited by many substances; or to the force by which the substances constituting a compound are held together. The tendency of any given element to unite with a number of other elements varies greatly. Chlorine, for instance, unites with great readiness with most metals and with many non-metallic elements, much heat being produced during the union; but it has little or no affinity for, or tendency to combine with, oxygen, so that compounds of chlorine with oxygen can only be obtained by roundabout methods, and are very liable to sudden and explosive decomposition into chlorine and oxygen. Where the affinity of elements for each other is great, the compounds produced by their union are decomposed with difficulty, and where the affinity is feeble, decomposition is easily effected. See also CHEMISTRY.