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ERIC Number: EJ820758
Record Type: Journal
Publication Date: 2007-Mar
Pages: 4
Abstractor: As Provided
Reference Count: 24
ISSN: ISSN-0021-9584
Effect of a Perturbation on the Chemical Equilibrium: Comparison with Le Chatelier's Principle
Torres, Emilio Martinez
Journal of Chemical Education, v84 n3 p516-519 Mar 2007
This article develops a general thermodynamic treatment to predict the direction of shift in a chemical equilibrium when it is subjected to a stress. This treatment gives an inequality that relates the change in the perturbed variable and the change that the equilibrium shift produces in the conjugated variable. To illustrate the generality of this approach, it has been applied to predict the direction of shift caused by changes of pressure, volume, and amount of substance. In this last case, the well-known unexpected shift in the ammonia synthesis equilibrium upon addition of nitrogen is easily explained. From the above referred inequality and the stability criteria of thermodynamics some conclusions have been obtained about the direction of shift in terms of extensive and extensive variables. This article is suitable for physical chemistry courses. (Contains 1 table, 3 figures, and 5 notes.)
Division of Chemical Education of the American Chemical Society. Subscription Department, P.O. Box 1267, Bellmawr, NJ 08099-1267. Tel: 800-691-9846; Tel: 856-931-5825; Fax: 856-931-4115; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Research
Education Level: Higher Education; Postsecondary Education
Audience: Teachers
Language: English
Sponsor: N/A
Authoring Institution: N/A