ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
For systems of chemical reactions the phenomenological equations of nonequilibrium thermodynamics display the differential symmetry of Onsager reciprocity in general only for stationary states in the vicinity of thermodynamic equilibrium, as is well known. It will be shown here, however, that systems of chemical reactions, on the macroscopic, phenomenological level of chemical kinetics, do show a less stringent symmetry at all stationary states arbitrarily far from equilibrium. The key is a reformulation of the kinetic equations for single chemical reactions as resistive laws relating the force driving a reaction to the rate of the reaction through a (nonlinear) generalized chemical resistance; these laws are analogous to the "voltage=current times resistance'' laws for resistive elements in electrical networks. The resistive laws for single reactions then lead naturally to stationary state relations for systems of coupled chemical reactions of the form of the phenomenological equations of nonequilibrium thermodynamics, and these relations display algebraic symmetry at stationary states arbitrarily far from equilibrium, although the differential symmetry of Onsager reciprocity is in general not valid. An example illustrates the relation of the symmetry property for chemical reactions to that displayed by RC electrical networks and how the chemical symmetry follows from analogs of Kirchhoff's laws obeyed by systems of chemical reactions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.453341
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