ISSN:
1572-8927
Keywords:
Sea salts
;
NaCl
;
Na2SO4
;
MgSO4
;
MgCl2
;
volumes of mixing
;
densities
;
cross-square rule
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The densities of mixtures of the six possible combinations of the four major sea salts (NaCl, Na2SO4, MgCl2, and MgSO4) have been measured at a constant ionic strength of I=3.0 at the temperatures 5, 25, 55, and 95°C. The results have been used to determine ΔVm, the volume change for mixing the major sea salts, which were fitted to equations of the from $$\Delta V{\text{m = }}y2y3I^2 \left[ {v0 + v1\left( {1 - 2y{\text{3}}} \right)} \right]$$ where y1 is the molal ionic strength fraction of solute i, and vo and v1 are parameters related to the interaction of like-charge ions. The cross-square rule was verified at each of the temperatures of study, but the rule did not hold as well at the higher temperatures. The temperature dependence of the volume change for mixing ΔVm was examined for each of the six mixtures. It was found that the two mixtures NaCl−Na2SO4 and MgSO4−MgCl2 showed little or no variation of ΔVm with temperature, while the other mixtures showed considerable temperature dependence. These results indicate that the anion-anion interactions of Cl− and SO 4 2− do not vary with temperature, while the cation-cation interactions of Na+ and Mg2+ are temperature sensitive. Explanations for these results based on ion-water inter actions are presented.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00648598
Permalink
