Chemical reaction: Difference between revisions

Revision as of 08:52, 19 November 2005

Revision as of 08:58, 19 November 2005

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A reaction is called [[spontaneous process|spontaneous]] if its thermodynamically favoured, by that meaning that it causes a net increase on [[entropy]]. Spontaneous reactions (in opposition to non-spontaneous reactions) do not need external perturbations (such as energy supplement) to happen. In a system at chemical equilibrium, it is expected to have larger concentrations of the substances formed by the spontaneous direction of the process.

Thus, in a '''global''' closed system (which it strictly isn't), spontaneous reactions may be understood to occur without human interference. Most spontaneus reactions in this system are exothermic (such as [[rust]]ing) or [[sedimentationmetamorphosis]], thus increasing the global entropy, though [[photosynthesis]] is an important exeption (in a global system).

==Energy and reactions==