ISSN:
1572-8927
Keywords:
Heat capacity
;
enthalpy of dilution
;
heat of dilution
;
relative apparent molal enthalpy
;
alkali halide
;
water
;
aqueous solution
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The enthalpies of dilution and volumetric specific heats of most alkali halides were measured in water at 25°C with flow microcalorimeters in the concentration range 0.01 to 1m. Apparent molal relative enthalpiesφ L, derived from the enthalpies of dilution, can be represented by a parametric equation in molality. Combiningφ L with osmotic data, excess entropies can be calculated. Excess free energies, enthalpies, and entropies are compared at 0.5m, and the observed trends are consistent with a model of structural interactions in aqueous alkali halide solutions. The apparent molal heat capacitiesφ C were fitted with the equationφ C=φ C ° +AC(d0m)1/2+B C m. Theφ C ° are, in general, additive to better than 1 J-K−1-mole−1 and reflect mostly the structural part of ion-solvent interactions. Takingφ C ° (H+)=0, conventional ionicφ C ° are obtained. The parameterB C for different pairs of ions follows approximately the same trends as the corresponding parameterB V for apparent molal volumes and seems to reflect structural interactions between the ions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00648229
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