Abstract
IT is well known that the Gibbs Phase Rule as applied to equilibrated macro-systems subject to changes of temperature, pressure and concentration may be written in the form where P is the number of phases, F the number of degrees of freedom and C the number of components. In applying the equation to physical and chemical equilibrium, the number of components C is taken as the minimum number of independently variable constituents in terms of which the equilibrium may be expressed in the form of a chemical equation. The term 'number of components' has thus to bear the brunt of the matter and assume a responsibility not shouldered by the equation itself. In fact, it is frequently necessary to write out a properly balanced chemical equation in order to decide upon the number of components in the system. Moreover, the equation cannot be applied without making allowance for certain restrictions when the phases approach identity, as in critical phenomena, or when one of the substances is kept in a definite weight -ratio to some other substance in the system, as in dissociation phenomena.
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BOWDEN, S. A Modified Phase Rule Equation. Nature 141, 331 (1938). https://doi.org/10.1038/141331a0
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DOI: https://doi.org/10.1038/141331a0
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