Measurement of Densities, Speed of sounds, and Water Activities for ternary system PEG۴۰۰۰+KNa(Tartrate)+H۲O at different temperatures

Thermodynamic properties of aqueous polymer-salt systems are necessary for a fundamental understanding of the phase-forming ability and also for the development of theoretical models for the prediction of the partitioning behavior of the two-phase system [۱]. In this work, densities, speed of sound and water activities of equeous potassium sodium tartrate+ PEG۴۰۰۰ solutions have been measured and to calculate accurate limiting apparent volumes in concentration (۰.۰۳ mol. kg-۱) of PEG. From the measurements of water activities by isopiestic methods, values of the vapor pressure of solutions were determined at T= ۲۹۸.۱۵ K. The experimental water activities have been correlated successfully with the Pitzer equation. The experimental density and speed of sound data were used to obtain apparent molar volume and apparent molar compressibility values at T= (۲۹۸.۱۵, ۳۰۸.۱۵, and ۳۱۸.۱۵) K, and these data were satisfactorily fitted to the Redlich-Mayer equations [۲].

کلیدواژه ها:

density ، water activity ، speed of sound ، isopiestic.