Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Density and activity of pertechnetic acid aqueous solutions at T = 298.15 K

Moeyaert, P., Abiad, L., Sorel, C., Dufreche, J.-F., Ruas, A., Moisy, P.[Ph.], Miguirditchian, M.
J. Chem. Thermodyn. 2015, 91, 94-100
ABSTRACT
The previous isopiestic investigations of HTcO4 aqueous solutions at T = 298.15 K are believed to be unreliable, because of the formation of a ternary mixture at high molality. Consequently, published isopiestic molalities for aqueous HTcO4 solutions at T = 298.15 K were completed and corrected. Binary data (variation of the osmotic coefficient and activity coefficient of the electrolyte in solution in the water) at T = 298.15 K for pertechnetic acid HTcO4 were determined by direct water activity measurements. These measurements extend from molality m = 1.4 mol kg 1 to m = 8.32 mol kg 1. The variation of the osmotic coefficient of this acid in water is represented mathematically. Density variations at T = 298.15 K are also established and used to express the activity coefficient values on both the molar and molal concentration scale. The density law leads to the partial molar volume variations for aqueous HTcO4 solutions at T = 298.15 K, which are compared with published data.
Compounds
# Formula Name
1 HO4Tc pertechnetic acid
2 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
  • 1
  • (Relative) activity - 2 ; Liquid
  • Molality, mol/kg - 1; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Novasina AW-Center water activity meter
  • 31
  • POMD
  • 2
  • 1
  • Mass density, kg/m3 ; Liquid
  • Molality, mol/kg - 1; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Vibrating tube method
  • 50