Evaluation of thermodynamic functions from equilibrium constants

Abstract

A new family of completely general equilibrium equations has been developed to represent the temperature dependence of reaction equilibrium constants in terms of the reaction standard thermodynamic function changes at a chosen reference temperature. Evaluation of these equilibrium equations by the method of least squares provides the best unbiased estimates for the standard thermodynamic function changes and their standard errors which are readily determined for the first time. Application of the equations to the ionization of aqueous cyanoacetic acid furnishes a more general representation of the data than comparable empirical relations. Use of the new equations is recommended when it is required to predict both the values and errors on standard thermodynamic function changes from the temperature dependence of reaction equilibrium constants.

The concentration and isotopic fractionation of gases dissolved in freshwater in equilibrium with the atmosphere. 1. Oxygen

“…(Throughout this paper we shall use T for kelvin temperatures and 1 for Celsius temperatures.) Clarke and Glew (1966) presented a systematic treatment of the generalized Valcntiner . ?unction In k = A, + (AI/T) + AJn T + A3T + A4T' + , , ,…”

“…Furthermore, Benson et al have shown that Eq. 3 follows from a systematic thermodynamic analysis that is equivalent to the Clarke and Glew (1966) treatment of the generalized Valentiner function. Our purpose in this paper is to derive from these new results very accurate values for the various quantities commonly used to specify equilibrium concentrations of oxygen in freshwater from 0" to 40°C.…”

Optimization of Productivity and Thermodynamic Performance of Metabolic Pathways

“…The standard formation Gibbs free energy of specie i at an ionic strength I can be calculated from the one at zero ionic strength using Eq. (2) 21 .…”

Estimation and application of the thermodynamic properties of aqueous phenanthrene and isomers of methylphenanthrene at high temperature

“…Alternative pathways to thermodynamic properties of aqueous species starting with the properties of liquid compounds could be envisaged; however, the ∆G • f of the liquid 1-MP and 2-MP at 25 • C tabulated by Richard and Helgeson (1998) Experimental solubilities for crystalline P at ∼25-73 • C and for P and 1-MP at ∼5-30 • C were reported by Wauchope and Getzen (1972) and May et al (1983), respectively. In their study, May et al (1983) reported the corresponding standard thermodynamic properties using a mole-fraction standard state (Clarke and Glew, 1966). In order to ensure consistency with the molal standard state for aqueous species, we calculated values of the standard molal properties of solution (∆G • sol , ∆H • sol and ∆C • P,sol at 25 • C) for P and 1-MP using a least-squares fit of Eq.…”