A review of the osmotic coefficients of aqueous sulfuric acid at 25.degree.C

Abstract

The high temperature emf data obtained in this study and the calorimetric data of Predel and Stein suggest that the maximum heat of mixing is shifted towards the Ga rich side rather than centered at xoa = 0.5.

Compaction and Swelling of Ca-Smectite in Water and in CaCl2 Solutions: Water Activity Measurements and Matrix Resistance to Compaction

“…As for charged membranes, the number of ions into which the electrolyte (i.e.,the membrane) dissociates is not known; hence, the deft- Figure 4 with the osmotic product for CaC12, as obtained from the data compiled in Rard et al (1977). To permit comparison, the osmotic product for CaCI2 was based on the chloride molality.…”

“…The values of aw* and aw~* can be calculated from the results of the water-clay systems and the data compiled in Rard et aL (1977). For the higher water contents, the product aw* x aw* was found to exceed slightly aw0, which contradicts the first condition.…”

Refined electrolyte‐NRTL model: Activity coefficient expressions for application to multi‐electrolyte systems

“…Later, Cherif et al 13 extended the H 2 SO 4 model of Pitzer et al 15,66 by including detailed speciation data in the experimental database used to fit the Pitzer model parameters. They fitted their model to the Raman spectroscopic measurements of Young et al 52 and Chen and Irish 42 and to the osmotic coefficient data of Robinson and Stokes, 8 Zeleznik 40 and Rard et al 37 They simulated the aqueous sulfuric acid solution up to 27 molal, but did not consider hydrates, H 2 SO 4 dissociation equilibria and ions-water complex formation. Wang et al 16,70 presented a speciation based version of the UNIQUAC model, 71 which they fitted to the vapor partial pressure data of Gmitro and Vermeulen 36 and heat capacity data of Zaytsev and Aseyev.…”

“…72 In their approach the bisulfate anion was considered as the ionic pair of a hydrogen cation and a sulfate anion, while hydration was considered for both the hydrogen and sulfate ions. They represented the osmotic coefficient and mean activity coefficient data of Rard et al, 37 but failed to represent the speciation data of Chen and Irish, 42 Knopf et al 44 and Myhre et al 50 It is noteworthy that they fitted a very large number of parameters (the hydration numbers of the ions, the NRTL interaction parameters and the equilibrium constant of the bisulfate dis- [Color figure can be viewed in the online issue, which is available at www.interscience. sociation) and noted that thermodynamic quantities, such as the osmotic coefficient and the speciation data, are very sensitive to the model parameters.…”

“…To derive these averaged values lower weights were given to the measurements of Librovich and Maiorov, 45 because of their different treatment of their spectroscopy measurements, while the measurements of Hood and Reilly 43 at concentrations below 2 m were removed from the database, as they do not agree with the other available experimental data. 15 Finally, the mean molal stoichiometric activity coefficients proposed by Zeleznik, 40 Rard et al 37 and Staples 38 were used to examine the validity of the application of the hydration theory of Robinson and Stokes as expressed by Eq. 17.…”