Freezing points, osmotic coefficients, and activity coefficients of salts in N-methylacetamide. II. Tetraalkylammonium halides and some alkali metal formates, acetates, and propionates

1971 ◽  
Vol 75 (15) ◽  
pp. 2319-2325 ◽  
Author(s):  
R. H. Wood ◽  
R. W. Kreis
1965 ◽  
Vol 20 (6) ◽  
pp. 1332-1336 ◽  
Author(s):  
Edward W. Moore ◽  
James W. Ross

In the investigation of numerous physiological phenomena it is the activity of an ion species which is desired, rather than stoichiometric concentration. The calculation of mean ionic activity from known concentration data requires accurate activity coefficients (ggr). This report concerns the determination of ggrNaCl and ggrCaCl2 in mixed NaCl-CaCl2 solutions by potentiometric measurement with a sodium-selective glass electrode-Ag/AgCl electrode system over the ionic strength range 0.05–0.5 m. Log ggrNaCl varied linearly, at constant total ionic strength, with the ionic strength of CaCl2 in the mixture, in accordance with Harned's rule. From data thus obtained, ggrCaCl2 coefficients in such mixed solutions have been calculated and compared with values calculated from published osmotic data. Resulting activity coefficient curves for ggrCaCl2 are presented over the concentration range encountered in serum and other extracellular fluids. Note: (With the Technical Assistance of Leonard Kaye and Leonard L. Anderson) glass electrodes; ion interaction; electrolyte metabolism; Harned's rule; membrane transport; osmotic coefficients Submitted on March 11, 1965


1990 ◽  
Vol 68 (2) ◽  
pp. 294-297 ◽  
Author(s):  
Ch. Venkateswarlu ◽  
J. Ananthaswamy

The activity coefficients of NaCl in the NaCl–NiCl2–H2O system were estimated at 25, 35, and 45 °C and total ionic strengths of 0.5, 1.0, 2.0, and 3.0 m by an EMF method using a Na-ion selective electrode and a silver–silver chloride reference electrode. The Harned coefficients were calculated at all the temperatures studied. At 25 °C the data were analysed using the Pitzer formalism. The osmotic coefficients and the excess free energies of mixing were also calculated at 25 °C. Keywords: activity coefficients, sodium chloride, nickel chloride, Pitzer equations, thermodynamics.


1994 ◽  
Vol 49 (9) ◽  
pp. 1179-1182 ◽  
Author(s):  
Kerstin Müller ◽  
Klaus-Jürgen Range ◽  
Anton M. Heyns

Single crystals of sodium formate dihydrate, NaHCO2·2H2O, have been prepared from aqueous solutions of sodium formate, NaHCO2, via the trihydrate, NaHCO2-3H2O. They are orthorhombic, space group Cmca, with a = 7.070(4), b = 14.534(2), c = 8.706(2) Å and Z = 8. The structure, including the hydrogen atoms, was refined to R = 0.054, Rw = 0.065 for 479 unique reflections with I > 3 σ (I). It comprises buckled layers formed by NaO6 octahedra which are edge- and corner-sharing. The octahedral coordination of the sodium ions is achieved by two oxygen atoms from two different end-on bonded formate ions and four water oxygen atoms. The O···H distances show clearly that strong hydrogen bonds are not involved in the bonding system


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