Thermodynamics of Na2SO4(aq) at temperatures T from 273 K to 373 K and of {(1-y)H2SO4+yNa2SO4}(aq) at T = 298.15 K

Isopiestic determination of the osmotic and activity coefficients of Rb 2SO4 (aq) and Cs 2SO 4(aq) at T= (298.15 and 323.15) K, and representation with an extended ion-interaction (Pitzer) model

“…(47) Holmes and Mesmer (1,2) and Hovey et al (48) found that assigning a smaller value of α M,X = (1.4 or 1.7) kg 1/2 · mol −1/2 , rather than the usual value of α M,X = 2.0 kg 1/2 · mol −1/2 , gave a significant improvement of the model fits for Na 2 SO 4 (aq) at various temperatures when using the usual form of Pitzer's equation which does not include an ionic-strength dependence for C M,X . Holmes and Mesmer (1) also found that although α M,X = 1.4 kg 1/2 · mol −1/2 gave a significantly improved representation for isothermal fits to the osmotic coefficients of both Na 2 SO 4 (aq) and Cs 2 SO 4 (aq) at higher temperatures, the traditional value α M,X = 2.0 kg 1/2 · mol −1/2 gave slightly better model fits at T = 298.15 K. However, the φ values of Cudd and Felsing for Cs 2 SO 4 (aq) at T = 298.15 K, (6) which were the only ones available at that temperature to Holmes and Mesmer, (2) · mol −1/2 .…”

Isopiestic determination of the osmotic and activity coefficients of {zH2SO4+(1−z) MgSO4}(aq) at the temperatureT=298.15 K. I. Results forz=(0.85811, 0.71539, and 0.57353)

“…(6,7) The thermodynamic activities for {zH 2 SO 4 + (1 − z)Na 2 SO 4 }(aq) have been analyzed by Pitzer's equations. (5,7,8) Although some ion pairing is known to occur in Na 2 SO 4 (aq) solutions to form NaSO − 4 (aq) ion pairs, these ion pairs are weak enough that they can be ignored in the thermodynamic analysis with Pitzer's equations. (9,10) Thus, the only equilibrium that need be considered in the mixtures is that for formation of HSO − 4 (aq).…”

“…In most cases the experimental thermodynamic results are limited to a small portion of the available composition region. The most thoroughly studied of these systems is {zH 2 SO 4 + (1 − z)Na 2 SO 4 }(aq) for which isopiestic results are available up to supersaturated molalities for 1 e z e 0 at the temperature T = 298.15 K, (3)(4)(5) and for 0.5 e z e 0 at elevated temperatures. (6,7) The thermodynamic activities for {zH 2 SO 4 + (1 − z)Na 2 SO 4 }(aq) have been analyzed by Pitzer's equations.…”

Dissolution enthalpy of anhydrous sodium sulfate in water. Experimental measurements and treatment with the electrolyte-NRTL model

“…Therefore, experimental and theoretical investigations of Na 2 SO 4 (aq) are numerous and most studies (4)(5)(6)(7)(8) are devoted to the application of Pitzer's ion-interaction model. (9) In these papers, authors considered simultaneously equilibrium and calorimetric data.…”