Thermodynamics, information from

Studies of the kinetics of chemical equilibrium (Reactions 2.3/—2.3) have provided very accurate thermodynamic information from the series... 

Thermodynamic Information from Galvanic Cell Measurements... 

THERMODYNAMIC INFORMATION FROM GALVANIC CELL MEASUREMENTS... 

The formation of aqueous selenium(IV)-fluoride complexes in solutions of high HF(aq) concentration was detected by Milne [87M1L]. The study was based on Raman spectroscopic measurements and showed, at 28 M HF, the presence of new bands in addition to those of H2Se03(aq). The bands were interpreted as originating from a species HSe02F(aq). At even higher HF concentrations, > 50 M, additional Raman bands appeared and these were claimed to be due to a species SeOF2(aq). No attempts were made to elucidate thermodynamic information from the measurements. 

Nevertheless, assuming that the molecular distribution functions are given, then we have a well-established theory that provides thermodynamic information from a combination of molecular information and MDFs. The latter are presumed to be derived either from experiments, from simulations, or from some approximate theories. The main protagonists in this route are the pair correlation functions once these are known, a host of thermodynamic quantities can be calculated. Thus, the less ambitious goal of a molecular theory of solutions has been for a long time route II, rather route I. 

This basic instrumentation can be complemented in various ways. For instance, sudden pressure changes may be applied to the system, thus obtaining additional thermodynamic information from the so-called pressure perturbation calorimetry . In this method the heat consumed or released after a pressure jump is measured, and from this volume changes associated with phase transitions may be derived. Another interesting modification is... 

For systems of the present type it is possible to obtain equilibrium information from two sources in the usual manner via the vapor pressmes of the solvent above the solutions within range HI (chemical potential of the solvent) and additionally from the saturatitMi composition w of the polymer (chemical potential of the polymer). The thermodynamic craisistency of these data was documented [52] by predicting w (liquid/soUd equilibrium) from the information of liquid/gas equilibria. This match of thermodynamic information from different sources is a further argument for the suitability to the present approach for the modeling of polymer-containing mixtures. 

The method described above is truly predictive in that it uses thermodynamic information from one- and, if possible, two-component systems to calculate the same or different thermodynamic properties of multi-component mixtures. There are other methods which have been used for the same purpose of which one of the most powerful is the generalization to mixtures of the Benedict-Webb-Rubin equation. 

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