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  • ionization  (4)
  • Pitzer theory  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 12 (1983), S. 401-412 
    ISSN: 1572-8927
    Keywords: Carbonic acid ; ionization ; Pitzer parameters ; weak acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The stoichiometric pK2 * and pK2 * for the ionization of carbonic acid has been determined from emf measurements in NaCl solutions with small amounts of MgCl2 from I=0.5 to 6.0 molal at 25°C. Our results at low ionic strengths (I=0.7) are in agreement with the measurements of Dyrssen and Hansson and Pytkowicz and Hawley. Our results have been analyzed using the ion pairing model and Pitzer's specific interaction equations. From the values of pK1 *, we have determined the Pitzer parameters β0[Mg (HCO3)2] = 0.0193 and β1[Mg (HCO3)2] = 0.0193 which reproduces the pK1 * results to ±0.01. The values of pK2 * were used to determine β0(MgCO3) = 2.833, β1(MgCO3) = -15.069, β2(MgCO3) = -204.90 and Cϕ (MgCO3)=−0.970 which reproduces the pK2 *′ s to ±0.02. The pK2 * results could be reproduced to the same precision with fewer parameters using the ion pairing model [pK(MgCO3)=3.00 and log γ (MgCO3)=0.0560 I].
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  • 2
    ISSN: 1572-8927
    Keywords: Densities ; partial molal volumes ; KCl ; K2SO4 ; Pitzer theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The densities of KCl and K2SO4 were measured from dilute solutions to saturation from 5 to 95°C. The data were combined with literature data to produce density and apparent molal volume, Vφ, equations from 0 to 100°C and to saturation. The standard deviations of the density equations were 30×10−6 g-cm−3 and 32×10−6 g-cm−3, respectively, for KCl and K2SO4. Pitzer equations were used to fit the Vφ data. The resulting infinite dilute partial molal volumes, Vo, were in reasonable agreement with literature data. The densities of the mixtures of the six combinations of the salts KCL, K2SO4 NaCl and Na2SO4 were measured at I=2.0 and t=5, 25, 55 and 95°C. The resulting volumes of mixing were fitted to equations of the form $$\Delta V_m = y(1 - y)I^2 [\nu _0 + \nu _1 (1 - 2y)]$$ wherev 0 andv 1 are interaction parameters. The cross square rule is valid over the entire temperature range although the deviations are larger at higher temperatures. Pitzer θ NaK v and $$\theta _{ClSO_4 }^v $$ parameters were determined from the common ion mixtures. The values of θ NaK v were small and not strongly dependent upon temperature. The values of $$\theta _{ClSO_4 }^v $$ were also small and changed considerably with temperature.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 12 (1983), S. 233-254 
    ISSN: 1572-8927
    Keywords: density ; sound speed ; compressibility ; partial molal volume ; NaHCO3 ; Na2CO3 ; carbonic acid ; ionization ; pressure effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The densities and the sound speeds of aqueous NaHCO3 and Na2CO3 solutions were measured from 0.05 to 1.0m and from 0 to 45°C. These data were fitted to functions of molality and temperature and were used to calculate the apparent molal volumes Vϕ and compressibilites κφ of these solutions. Polynomial expression for Vϕ and κφ as functions of molality and temperature have been determined. The partial molal volumes and compressibilities of these solutions and literature data have been used to determine the volume ΔV and compressibility Δκ changes for the ionization of carbonic acid in aqueous solutions. These values of ΔV and Δκ have been used to estimate the effect of pressure on the ionization constants for carbonic acid from 0 to 45°C. The calculated pressure coefficients are in good agreement with the measured values.
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  • 4
    ISSN: 1572-8927
    Keywords: Densities ; partial molal volumes ; NaCl ; Na2SO4 ; MgCl2 ; MgSO4 ; Pitzer theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The densities of the major sea salts (NaCl, Na2SO4, MgCl2, and MgSO4) have been measured from 25 to 95°C and to saturation. These results have been combined with literature data and fitted to equations of the form $$\Delta d = Am{\text{ }} + {\text{ }}Bm^{3/2} {\text{ }} + {\text{ }}Cm^2 {\text{ }} + {\text{ }}Dm^{5/2} $$ where Δd=d−do (do is the density of water) and A, B, and C, etc., are polynomial functions of temperature. The standard deviations of the fits were better than ±50×10−6 g-cm−3 for all the salts from 0 to 95°C and to saturation. The apparent molal volumes Vϕ of the salts have been fitted to the equations of Pitzer. The infinite dilution values of Vϕ were in good agreement with literature data, provided the results were not overfit. The large deviations of Vϕ for MgSO4 from additivity as a function of concentration were attributed to the formation of MgSO4 ion pairs.
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  • 5
    ISSN: 1572-8927
    Keywords: Sound speeds ; compressibilities ; partial molal compressibilities ; NaCl ; Na2SO4 ; MgCl2 ; MgSO4 ; Pitzer theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The sound velocities of aqueous NaCl, Na2SO4, MgCl2, and MgSO4 solutions were measured from 25 to 95°C in 10o intervals from dilute to saturated solutions. The results were combined with our earlier data and fitted to functions of molality and temperature to within ±0.4 m-sec−1. The adiabatic compressibilities βS were calculated from sound speeds and used to calculate the adiabatic apparent molal compressibilities ξφ. Isothermal compressibilities β and isothermal apparent molal compressibilities χφ were calculated from βS using literature values for the expansibilities and heat capacities. The values of χφ were extrapolated to infinite dilution using the Debye-Huckel limiting law to determine partial molal compressibilities. The apparent molal compressibilities were fitted to Pitzer's equations. The Pitzer parameters for the concentration dependence of χφ were determined as a function of temperature. Correlations of χφ and Vφ at various temperatures were found for the electrolytes.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 5 (1976), S. 263-268 
    ISSN: 1572-8927
    Keywords: Molal volume ; heat capacity ; phenol ; nitrophenols ; cyanophenols ; sodium salts ; ionization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The apparent molal heat capacities $$\phi _{{\text{C}}_p }$$ have been determined at 25°C for phenol,meta-nitrophenol,para-nitrophenol,meta-cyanophenol, andpara-cyanophenol and the corresponding sodium salts in water at several concentrations. These values have been extrapolated to infinite dilution to provide the $$\bar C_p^o$$ values from which the heat capacity changes for the ionization of the aqueous phenols have been calculated. The observed $$\Delta \bar C_{p_i }^o$$ values are virtually identical within experimental error for the phenols studied. The volume data needed to calculate the $$\phi \bar C_p$$ values from the experimental data are also reported.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of atmospheric chemistry 8 (1989), S. 377-389 
    ISSN: 1573-0662
    Keywords: SO2 ; H2SO3 ; solubility ; ionization ; activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The pK 1 * and pK 2 * of H2SO3 have been determined in NaCl solutions as a function of ionic strength (0.1 to 6 m) and temperature (5 and 25 °C). The extrapolated values in water were found to be in good agreement with literature data. The experimental results have been used to determine the Pitzer interaction parameters for SO2, HSO 3 - and SO 3 - in NaCl solutions. The resultant parameters for NaHSO3 and Na2SO3 were found to be in reasonable agreement with the values for NaHSO4 and Na2SO4. It, thus, seems reasonable to assume that the interactions of Mg2+ and Ca2+ with HSO 3 - and SO 3 - can be estimated from the values with HSO 4 - and SO 4 - until experimental values are available. Measurements of pK 1 * and pK 2 * in artificial seawater were found to be in good agreement with the calculated values using the derived Pitzer parameters. It is, thus, possible to make reasonable estimates of the activity coefficients of HSO 3 - and SO 3 - ions and pK 1 * and pK 2 * for the ionization of H2SO3 in marine aerosols.
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