Water activity, density, sound velocity, refractive index and viscosity of the {(NH4)6Mo7O24 + poly(ethylene glycol) + H2O} system in the temperature range from 313.15 to 333.15 K: Experiment and modelling

Abstract

Experimental data of water activity, density, sound velocity, refractive index and viscosity of unsaturated solutions of {ammonium heptamolybdate + poly(ethylene glycol) + water} at (313.15, 323.15 and 333.15) K were obtained. The concentration range of the solutions was from 0 to 0.4 mass fraction of poly(ethylene glycol) with an average molar mass of 4000 g·mol−1 and from 0 to 0.17 mass fraction of (NH4)6Mo7O24. Additionally, water activities and physical properties of the constituent binary systems, {(NH4)6Mo7O24 + H2O and PEG 4000 + H2O}, were measured and modeled at the same temperatures of the ternary system. The modified Pitzer model for the representation of water activity was applied and the physical properties were correlated by the Othmer’s rule. Good agreement between the experimental and correlated data was obtained.