396.     BRYANT, W. M. D.  Calculations on Water-Gas Equilibrium.  Choice of Suitable Molecular-Heat Equations.  Heat of Reaction and Free Energy as a Function of the Temperature.  Ind. Eng. Chem., vol. 23, 1931, pp. 1019-1024, 1309; Chem. Abs., vol. 25, 1931, p. 5612.

      Thermal and equilibrium data for the water-gas reaction are assembled and discussed.  ∆H_298.1 for the reaction CO₂(g)+H₂(g)=CO(g)+H₂O(g) is calculated to be 9,751 cal.  This value is combined with molecular-heat equations from several sources to yield expressions for ∆H as a function of the temperature.  These equations, in turn, are used to show the order of agreement existing between molecular-heat of different sources.  For this reaction, specific-heat equations of Lewis and Randall, of Eucken, and of Eastman give similar results.  Partington and Shilling’s equations do not agree with these results.  Expressions for the free-energy change, ∆F°, and its temperature coefficient is derived, as well as for the corresponding reaction isochores.  The equilibrium value of Neumann and Köhler at 1,259.1°K. is used to determine the integration constants.  The molecular-heat equations of Lewis and Randall, of Eucken, and of Eastman satisfactorily reproduce the experimental equilibrium constants in the water-gas reaction.  Partington and Shilling’s molecular-heat equations fail to reproduce these values. ∆F°_298.1 for the water-gas reaction is calculated.   Numerical results ranging 6,828-6,750 cal. are obtained, depending on the specific heats used.  These values constitute the first step in a recalculation of the free energy of formation of CO and CO₂.