Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

Water activity and activity coefficients of the mixed electrolytes {yNH4Cl + (1-y)NH4NO3} (aq) at 298.15K

Guendouzi, M. E.[Mohamed El], Errougui, A.[Abdelkbir]
Fluid Phase Equilib. 2005, 236, 1-2, 205-211
ABSTRACT
Water activities have been measured for the system {yNH4Cl + (1-y)NH4NO3 + H2O}, at total electrolyte molalities from 0.2 mol/kg to about saturation for ionic-strength fractions of NH4Cl, y = 0.20, 0.50 and 0.80, at temperature 298.15 K, by the hygrometric method. The obtained data allow the deduction of osmotic coefficients. The experimental results are compared with the Leitzke and Stoughton rule, and Kusik and Meissner, Robinson and Stokes and Pitzer models. Good accuracy is obtained by Pitzer s model. The use of Pitzer s model involves the adjustment of the parameters e and o. The other models do not require parameter fitting. From these measurements, mixing ionic parameters are determined and used to predict the solute activity coefficients in the mixture. The obtained results are used to calculate the excess Gibbs energy at total molalities for ionic-strength fractions y.
Compounds
# Formula Name
1 ClH4N ammonium chloride (NH4Cl)
2 H4N2O3 ammonium nitrate
3 H2O water
Datasets
The table above is generated from the ThermoML associated json file (link above). POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied; the numbers refer to the table of compounds on the left.
Type Compound-# Property Variable Constraint Phase Method #Points
  • POMD
  • 2
  • 3
  • 1
  • (Relative) activity - 3 ; Liquid
  • Molality, mol/kg - 1; Liquid
  • Molality, mol/kg - 2; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • hygrometric method
  • 30