TY  - JOUR
AU  - Ivanović, Tijana
AU  - Popović, Daniela Ž.
AU  - Miladinović, Jelena
AU  - Rard, Joseph A.
AU  - Miladinović, Zoran P.
AU  - Pastor, Ferenc
PY  - 2020
UR  - https://cherry.chem.bg.ac.rs/handle/123456789/3663
AB  - Isopiestic measurements have been made at 55 compositions of the {yK2HPO4 + (1 − y)KH2PO4}(aq) system at T = (298.15 ± 0.01) K, 11 for each of the limiting binary solutions and 33 for mixture compositions at K2HPO4 stoichiometric ionic strength fractions y = (0.23330, 0.47671, and 0.73177), using KCl(aq) as the reference standard. Model parameters for the binary subsystems were evaluated at this temperature for an extended form of Pitzer's ion-interaction model and also for the Clegg, Pitzer and Brimblecombe model based on the mole-fraction-composition scale, using the present isopiestic results along with critically-assessed osmotic coefficients for both of these aqueous electrolytes as extracted from the published literature. The thermodynamic models for KH2PO4(aq) extend to slightly above the saturated solution molality at T = (298.15 ± 0.01) K, whereas those for K2HPO4(aq) extend to m = 9.7429 mol·kg−1, which is the molality of the saturated solution, also at T = (298.15 ± 0.01) K. These results yield the CODATA-compatible standard Gibbs energy of formation ΔfGmo(K2HPO4·3H2O,cr,298.15K)=-2367.70±1.60kJ·mol-1. The 33 osmotic coefficients for the ternary mixtures were likewise represented with these models, using both the usual Pitzer mixing terms and also Scatchard's neutral-electrolyte model mixing terms for the extended ion-interaction model. Two mixing parameters are needed for each of the three models for {yK2HPO4 + (1 − y)KH2PO4}(aq), and both of these ion-interaction models give similar high-quality representations of the experimental results. However, the Clegg, Pitzer and Brimblecombe model had more difficulty in representing the osmotic coefficients of K2HPO4(aq), especially below 3 mol·kg−1, and consequently the corresponding mixture model with two mixing parameters is slightly less accurate for representing the osmotic coefficients. The maximum difference in calculated values of the mean molality-based activity coefficients for the two recommended extended Pitzer models with the different types of mixing terms are 0.0061 for the trace activity coefficient of K2HPO4(aq) in KH2PO4(aq) but with much better agreement at most mixture compositions.
PB  - Elsevier
T2  - Journal of Chemical Thermodynamics
T1  - Isopiestic determination of the osmotic and activity coefficients of {yK2HPO4 + (1 − y)KH2PO4}(aq) at T = 298.15 K
VL  - 142
SP  - 105945
DO  - 10.1016/j.jct.2019.105945
ER  - 

@article{
author = "Ivanović, Tijana and Popović, Daniela Ž. and Miladinović, Jelena and Rard, Joseph A. and Miladinović, Zoran P. and Pastor, Ferenc",
year = "2020",
abstract = "Isopiestic measurements have been made at 55 compositions of the {yK2HPO4 + (1 − y)KH2PO4}(aq) system at T = (298.15 ± 0.01) K, 11 for each of the limiting binary solutions and 33 for mixture compositions at K2HPO4 stoichiometric ionic strength fractions y = (0.23330, 0.47671, and 0.73177), using KCl(aq) as the reference standard. Model parameters for the binary subsystems were evaluated at this temperature for an extended form of Pitzer's ion-interaction model and also for the Clegg, Pitzer and Brimblecombe model based on the mole-fraction-composition scale, using the present isopiestic results along with critically-assessed osmotic coefficients for both of these aqueous electrolytes as extracted from the published literature. The thermodynamic models for KH2PO4(aq) extend to slightly above the saturated solution molality at T = (298.15 ± 0.01) K, whereas those for K2HPO4(aq) extend to m = 9.7429 mol·kg−1, which is the molality of the saturated solution, also at T = (298.15 ± 0.01) K. These results yield the CODATA-compatible standard Gibbs energy of formation ΔfGmo(K2HPO4·3H2O,cr,298.15K)=-2367.70±1.60kJ·mol-1. The 33 osmotic coefficients for the ternary mixtures were likewise represented with these models, using both the usual Pitzer mixing terms and also Scatchard's neutral-electrolyte model mixing terms for the extended ion-interaction model. Two mixing parameters are needed for each of the three models for {yK2HPO4 + (1 − y)KH2PO4}(aq), and both of these ion-interaction models give similar high-quality representations of the experimental results. However, the Clegg, Pitzer and Brimblecombe model had more difficulty in representing the osmotic coefficients of K2HPO4(aq), especially below 3 mol·kg−1, and consequently the corresponding mixture model with two mixing parameters is slightly less accurate for representing the osmotic coefficients. The maximum difference in calculated values of the mean molality-based activity coefficients for the two recommended extended Pitzer models with the different types of mixing terms are 0.0061 for the trace activity coefficient of K2HPO4(aq) in KH2PO4(aq) but with much better agreement at most mixture compositions.",
publisher = "Elsevier",
journal = "Journal of Chemical Thermodynamics",
title = "Isopiestic determination of the osmotic and activity coefficients of {yK2HPO4 + (1 − y)KH2PO4}(aq) at T = 298.15 K",
volume = "142",
pages = "105945",
doi = "10.1016/j.jct.2019.105945"
}

Ivanović, T., Popović, D. Ž., Miladinović, J., Rard, J. A., Miladinović, Z. P.,& Pastor, F.. (2020). Isopiestic determination of the osmotic and activity coefficients of {yK2HPO4 + (1 − y)KH2PO4}(aq) at T = 298.15 K. in Journal of Chemical Thermodynamics
Elsevier., 142, 105945.
https://doi.org/10.1016/j.jct.2019.105945

Ivanović T, Popović DŽ, Miladinović J, Rard JA, Miladinović ZP, Pastor F. Isopiestic determination of the osmotic and activity coefficients of {yK2HPO4 + (1 − y)KH2PO4}(aq) at T = 298.15 K. in Journal of Chemical Thermodynamics. 2020;142:105945.
doi:10.1016/j.jct.2019.105945 .

Ivanović, Tijana, Popović, Daniela Ž., Miladinović, Jelena, Rard, Joseph A., Miladinović, Zoran P., Pastor, Ferenc, "Isopiestic determination of the osmotic and activity coefficients of {yK2HPO4 + (1 − y)KH2PO4}(aq) at T = 298.15 K" in Journal of Chemical Thermodynamics, 142 (2020):105945,
https://doi.org/10.1016/j.jct.2019.105945 . .

TY  - JOUR
AU  - Ivanović, Tijana
AU  - Popović, Daniela Ž.
AU  - Miladinović, Jelena
AU  - Rard, Joseph A.
AU  - Miladinović, Zoran P.
AU  - Pastor, Ferenc
PY  - 2020
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/4775
AB  - Isopiestic measurements have been made for aqueous solutions of the common sodium cation mixtures of NaH2PO4and Na2HPO4at T = 298.15 ± 0.01 K, at NaH2PO4ionic strength fractions y = (0, 0.24851, 0.49862, 0.74544, and 1), where the ionic strength fractions were calculated by assuming complete electrolytic dissociation of NaH2PO4as 1:1 and Na2HPO4as 2:1 electrolytes; CaCl2(aq) was used as the reference standard solution. Model parameters for an extended form of Pitzer's ion-interaction model and also for the Clegg-Pitzer-Brimblecombe equations based on the mole-fraction-composition scale were evaluated at T = 298.15 K for both NaH2PO4(aq) and Na2HPO4(aq) using the isopiestic results from this study (17 values each) together with numerous critically assessed osmotic coefficients for both electrolytes taken from the published literature. The thermodynamic models for NaH2PO4(aq) extend to m = 7.5 mol·kg-1, whereas those for Na2HPO4(aq) extend to m = 2.6050 mol·kg-1, which is well above the solubility limit for the thermodynamically stable phase Na2HPO4·12H2O(cr). The 51 osmotic coefficients for the ternary mixtures were treated with these two models together with Scatchard's neutral-electrolyte model; one previous set of osmotic coefficient values for {yNaH2PO4+ (1 - y)Na2HPO4}(aq) mixtures was found in the literature [ Scharge, T.; et al. J. Chem. Thermodyn. 2015, 80, 172-183 ], and hence an analysis and comparison were made of our results with theirs.
PB  - Amer Chemical Soc, Washington
T2  - Journal of Chemical and Engineering Data
T1  - Isopiestic Determination of Osmotic and Activity Coefficients of the { yNaH2PO4+ (1 - Y)Na2HPO4}(aq) System at T = 298.15 K
VL  - 65
IS  - 11
SP  - 5137
EP  - 5153
DO  - 10.1021/acs.jced.0c00281
ER  - 

@article{
author = "Ivanović, Tijana and Popović, Daniela Ž. and Miladinović, Jelena and Rard, Joseph A. and Miladinović, Zoran P. and Pastor, Ferenc",
year = "2020",
abstract = "Isopiestic measurements have been made for aqueous solutions of the common sodium cation mixtures of NaH2PO4and Na2HPO4at T = 298.15 ± 0.01 K, at NaH2PO4ionic strength fractions y = (0, 0.24851, 0.49862, 0.74544, and 1), where the ionic strength fractions were calculated by assuming complete electrolytic dissociation of NaH2PO4as 1:1 and Na2HPO4as 2:1 electrolytes; CaCl2(aq) was used as the reference standard solution. Model parameters for an extended form of Pitzer's ion-interaction model and also for the Clegg-Pitzer-Brimblecombe equations based on the mole-fraction-composition scale were evaluated at T = 298.15 K for both NaH2PO4(aq) and Na2HPO4(aq) using the isopiestic results from this study (17 values each) together with numerous critically assessed osmotic coefficients for both electrolytes taken from the published literature. The thermodynamic models for NaH2PO4(aq) extend to m = 7.5 mol·kg-1, whereas those for Na2HPO4(aq) extend to m = 2.6050 mol·kg-1, which is well above the solubility limit for the thermodynamically stable phase Na2HPO4·12H2O(cr). The 51 osmotic coefficients for the ternary mixtures were treated with these two models together with Scatchard's neutral-electrolyte model; one previous set of osmotic coefficient values for {yNaH2PO4+ (1 - y)Na2HPO4}(aq) mixtures was found in the literature [ Scharge, T.; et al. J. Chem. Thermodyn. 2015, 80, 172-183 ], and hence an analysis and comparison were made of our results with theirs.",
publisher = "Amer Chemical Soc, Washington",
journal = "Journal of Chemical and Engineering Data",
title = "Isopiestic Determination of Osmotic and Activity Coefficients of the { yNaH2PO4+ (1 - Y)Na2HPO4}(aq) System at T = 298.15 K",
volume = "65",
number = "11",
pages = "5137-5153",
doi = "10.1021/acs.jced.0c00281"
}

Ivanović, T., Popović, D. Ž., Miladinović, J., Rard, J. A., Miladinović, Z. P.,& Pastor, F.. (2020). Isopiestic Determination of Osmotic and Activity Coefficients of the { yNaH2PO4+ (1 - Y)Na2HPO4}(aq) System at T = 298.15 K. in Journal of Chemical and Engineering Data
Amer Chemical Soc, Washington., 65(11), 5137-5153.
https://doi.org/10.1021/acs.jced.0c00281

Ivanović T, Popović DŽ, Miladinović J, Rard JA, Miladinović ZP, Pastor F. Isopiestic Determination of Osmotic and Activity Coefficients of the { yNaH2PO4+ (1 - Y)Na2HPO4}(aq) System at T = 298.15 K. in Journal of Chemical and Engineering Data. 2020;65(11):5137-5153.
doi:10.1021/acs.jced.0c00281 .

Ivanović, Tijana, Popović, Daniela Ž., Miladinović, Jelena, Rard, Joseph A., Miladinović, Zoran P., Pastor, Ferenc, "Isopiestic Determination of Osmotic and Activity Coefficients of the { yNaH2PO4+ (1 - Y)Na2HPO4}(aq) System at T = 298.15 K" in Journal of Chemical and Engineering Data, 65, no. 11 (2020):5137-5153,
https://doi.org/10.1021/acs.jced.0c00281 . .