Calorimetric Properties of Hydrothermal Solutions

While the heat capacities at constant pressme are useful for calciflation of various thermodynamic quantities, related to Gibbs free energy for aqueous species, and chemical equilibria involving aqueous species, the isochoric heat capacity measurements are useftil in developing equations of state (EOS) because they yield valuable information about the second derivative of the pressure and of the Helmholtz energy with respect to temperature. Detailed comparisons of experimental Cv data with available EOS are needed to establish their accuracy. Cv experiments contain direct information on the curvature behavior of the p-T isochores, which are extremely important in the development of a reliable EOS. Furthermore, the temperature dependence of Cv at fixed density serves as a sensitive indicator of the phase transition boundary. Thus C measurements provide a tool for investigation of temperatures T and densities d on the coexistence ciuve, especially near the critical point. 

Hydrothermal Experimented Data Edited by V.M. Valyashko 2008 John Wiley Sons. Ltd. ISBN 978-0470-09465-5 

Most measurements of the isochoric heat capacity were made using a high-temperature, high-pressure adiabatic 

---

Chapter 7 (Calorimetric Properties of Hydrothermal Solutions, V. M. Valyashko (Russia) and M. S. Gruszkiewicz (USA)), indicates the experimentally determined calorimetric quantities of considerable current use, gives a brief description of experimental methods for hydrothermal measurements and contains a summary table with information about the systems studied and the corresponding calorimetric measurements. 

---