JCE Online Journal of Chemical Education
 | Subscriptions  | Software Orders  | Support  | Contributors  | Advertisers  | 

JCE Print

JCE Digital Library

JCE Software

Only@JCE Online

About JCE


  Home > JCE Print > Journal of Chemical Education > Issues > 1999  > August  >
Research: Science and Education
A Generalized Statement of the Law of Mass Action
James K. Baird
The University of Alabama in Huntsville, Department of Chemistry, Huntsville, AL 35899

Cover
August 1999
Vol. 76 No. 8
p. 1146

Abstract
When expressed in a generalized form in terms of thermodynamic activities, the law of mass action can be made to take into account the non-ideal behavior of reactants in solution in a way that is consistent with both equilibrium and non-equilibrium thermodynamics. Specifically, when combined with the principle of detailed balance, the generalized law of mass action predicts the thermodynamically exact result linking the forward and reverse rate constants, the equilibrium activities, and the equilibrium constant. For a reaction approaching equilibrium, it predicts in agreement with non-equilibrium thermodynamics a proportionality between the net reaction rate and the instantaneous Gibbs free energy of reaction. In the case of an irreversible reaction between ions in solution, the generalized law leads to the Brönsted-Bjerrum equation connecting the rate constant to the ionic strength. For reactions in the gas phase or in dilute ideal solution, the generalized law assumes the familiar form of the original Guldberg and Waage law of mass action (1864). Because of its universal character, the generalized law can be used as a unique starting point for a course in chemical kinetics.
More Information
*  Citation
Baird, James K. J. Chem. Educ. 1999 76 1146.
*  Keywords
Physical Chemistry; History / Philosophy; Aqueous Solution Chemistry; Intermolecular Forces; Kinetics; Thermodynamics
*  History
Created:
Last Updated:
July 8, 1999
June 23, 2005
  Home > JCE Print > Journal of Chemical Education > Issues > 1999 > August > Page 1146


Subscriptions

JCE HS CLIC

Our Secondary School editors work hard to distill all the JCE materials to produce a fraction of particular interest to high school teachers. We call it CLIC.


Contributions Welcome
JCE welcomes your submission

Advertisers
In recent years we have worked hard to better match our advertisers with our readers. When shopping for chemistry education materials, visit our advertisers' WWW sites first.

Be An Ambassador
Take JCE along on your outreach missions. Copies of the Journal, guest access to JCE Online, our publications catalog, and more are available for your participants.