Jan J. Spitzer

Apparent molar heat capacities and volumes of aqueous electrolytes: CaCl2, Cd(NO3)2, CoCl2, Cu(ClO4)2, Mg(ClO4)2, and NiCl2

We have used a flow calorimeter and a flow densimeter for measurements leading to apparent molar heat capacities and apparent molar volumes of six 2∶1 electrolytes in aqueous solution at 25°C. Results of these measurements have been used to derive apparent molar heat capacities and volumes at infinite dilution for all six electrolytes: CaCl2, Cd(NO3)2, CoCl2, Cu(ClO4)2, Mg(ClO4)2, and NiCl2.

Apparent molar heat capacities and volumes of aqueous electrolytes at 298.15 K: Ca(NO3)2, Co(NO3)2, Cu(NO3)2, Mg(NO3)2, Mn(NO3)2, Ni(NO3)2, and Zn(NO3)2☆

Abstract We have used a flow calorimeter and a flow densimeter for measurements leading to apparent molar heat capacities and apparent molar volumes of dilute aqueous solutions of Ca(NO 3 ) 2 , Co(NO 3 ) 2 , Cu(NO 3 ) 2 , Mg(NO 3 ) 2 , Mn(NO 3 ) 2 , Ni(NO 3 ) 2 , and Zn(NO 3 ) 2 at 298.15 K. The resulting apparent molar quantities have been extrapolated to infinite dilution to obtain the corresponding standard-state apparent and partial molar heat capacities and volumes. These latter values have been used for calculation of conventional ionic heat capacities and volumes of the M 2+ (aq) ions.

Interactions in aqueous nonelectrolyte systems. Gibbs energy of interaction of the ether group with the hydroxyl group and the amide group

Freezing temperatures of dilute aqueous solutions of equimolar mixtures of 1,3,5-trioxane with myo-inositol, d-mannitol, cyclohexanol, formamide, and acetamide, and 1,4-dioxane with myo-inositol, d-mannitol, formamide, and acetamide have been measured. These data yield pairwise Gibbs energies of interactions between the molecules in an aqueous solution. Using the group additivity principle, the results also yield the pairwise functional group Gibbs energies of interaction for the ether group with the hydroxyl and amide group. These results have been combined with all available data from the literature to yield the Gibbs energy and enthalpy of interaction of amides, ethers, alcohols, and saccharides in aqueous solution.

Apparent molar heat capacities and volumes of aqueous electrolytes at 25°C: Cd(ClO4)2, Ca(ClO4)2, Co(ClO4)2, Mn(ClO4)2, Ni(ClO4)2, and Zn(ClO4)2

We have used a flow calorimeter and a flow densimeter for measurements leading to apparent molar heat capacities and apparent molar volumes of aqueous solutions of Cd(ClO4)2, Ca(ClO4)2, Co(ClO4)2, Mn(ClO4)2, Ni(ClO4)2, and Zn(ClO4)2. The resulting apparent molar quantities have been extrapolated to infinite dilution to obtain the corresponding standardstate apparent and partial molar heat capacities and volumes. These latter values have been used for calculation of conventional ionic heat capacities and volumes.

The effect of ionic sizes on the potential distribution in the double layer in the absence of specific adsorption

Abstract By use of the linearized Poisson-Boltzmann equation, electrostatic calculations have been performed for a model of a planar double layer in which ionic sizes are considered explicitly in the absence of specific adsorption for surface charge densities near the potential of zero charge. The results of the calculations show that the differences in the ionic sizes become important above 0.05 M aqueous solution of 1:1 electrolytes at 25°C. The model qualitatively predicts a shift of the potential of point of zero charge with concentration, a reversal of potential sign, and a maximum in the potential function within the inner diffuse part of the double layer. These phenomena have been usually attributed to specific adsorption of ions. A consistent electrostatic approach to the double-layer theory is used in order to avoid the usual two-capacitor-in-series model, and suggestions for further development of this phenomenological approach are made.

On a possible relationship between stability ratios and electrophoretic mobilities of polymer latices

Abstract Qualitative interpretation of electrophoretic mobilities of two polymerically similar styrene-butadiene latices suggests that such colloids have surfaces composed of hydrophobic polyelectrolyte chains: the coiling-up of these chains at higher ionic strengths (giving higher surface charge density) and the classical double-layer compression may explain the often observed maxima in electrophoretic mobility versus ionic strength measurements. This hypothesis is corroborated by measurements of stability ratios at different ionic strengths, and also in the presence of a nonionic surfactant.

Gibbs energies of interaction of the CH2 and CHOH groups from freezing point data for aqueous binary mixtures of D-mannitol,myo-inositol, and cyclohexanol

Freezing temperatures of dilute aqueous solutions of D-mannitol, myo-inositol, D-mannitol + myo-inositol, D-mannitol + cyclohexanol, and myo-inositol + cyclohexanol have been measured over the concentration range 0.1 to 1.0 mol-kg−1. These data yield pairwise molecular Gibbs energies of interaction which have been corrected to 25°C and treated according to the Savage-Wood additivity principle to give pairwise functional group Gibbs energies of interaction for CH2/CH2, CH2/COOH, and CHOH/CHOH. Anomalous behavior of some systems is discussed in terms of the interactions.

Electrophoretic mobilities determined by the velocity—depth profile method and use of hydrolyzed potassium chromium sulphate sol as a reproducible test substance for microelectrophoresis

Abstract Measurements of electrophoretic mobilities by the stationary level method and by the velocity—depth profile method were compared experimentally and theoretically, leading to the conclusion that the velocity—depth profile method is more accurate and reliable. Electrophoretic mobilities of colloidal particles obtained by slow hydrolysis of 4.0 × 10 −4 molar solutions of KCr(SO 4 ) 2 . 12H 2 O were measured in electrophoretic cells of rectangular cross-section. It was found that the hydrolyzed potassium chromium sulphate hydrosol can be prepared reproducibly in a simple apparatus, with resulting colloidal particles that are suitable for use as a test substance for microscopic electrophoresis. The mobility was determined as +1.64 ± 0.12 (μm s −1 )/(V cm −1 ) at pH = 3.30 ± 0.02 and 25.0 ± 0.1°C.

Apparent molar heat capacities and volumes of aqueous electrolytes at 25°C: NaIO3, KMnO4, and MnCl2

Abstract We have used a flow calorimeter and a flow densimeter for measurements leading to apparent molar heat capacities and apparent molar volumes of dilute aqueous solutions of NaIO3, KMnO4, and MnCl2 at 25°C. These apparent molar quantities have been extrapolated to infinite dilution to obtain the corresponding standard state apparent and partial molar heat capacities and volumes. which have then been used for the calculation of conventional ionic heat capacities and volumes.

Freezing temperatures of aqueous solutions of hexamethylenetetramine with polyols, amides, and ethers

Freezing temperatures of dilute aqueous solutions of hexamethylenetetramine and mixtures of hexamethylenetetramine with myo-inositol, d-mannitol, cyclohexanol, formamide, acetamide, 1,4-dioxane, and 1,3,5-trioxane have been measured. These data yield pairwise molecular Gibbs energies of interaction between the molecules in an aqueous solution. Using the additivity principle, the results also yield the pairwise functional group Gibbs energies of interaction in an aqueous solution for the amine nitrogen with itself and with the hydroxyl, amide, ether, and methylene groups.