Skoči na glavni sadržaj

Izvorni znanstveni članak

Thermochemistry of Precipitation of Alkaline Earth Laurates

Vesna Hrust ; Laboratory of Physical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, 41001 Zagreb, P. O. Box 163, Croatia, Yugoslavia
Đurđica Težak ; Laboratory of Physical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, 41001 Zagreb, P. O. Box 163, Croatia, Yugoslavia


Puni tekst: engleski pdf 10.817 Kb

str. 129-138

preuzimanja: 435

citiraj


Sažetak

The solubility of alkaline earth laurates was studied in aqueous solutions as a function of temperature. Dissolution enthalpies AdH°, determined directly by calorimetry, were compared with the solubility data. The enthalpy change AdfiT0 showed linear dependence on temperature. The heat capacity change AdCp, calculated from AdH°vs. T plot, was found to be 1.1 kJ mol"1 K"1 for all salts.
The entropy change of dissolution AdS°, as obtained from solubility and calorimetiy, showed linear dependence on In T; AdCp, calculated from these plots, was the same as obtained from temperature dependence of the enthalpy.
Specific behaviour of each alkaline earth cation is characterized by the entropy change A<*S°, which is the lowest for calcium salt, thus explaining the irregular low solubility of calcium carboxylates. The so called compensation effect was explained in terms of the »critical compensation temperature®, which was found to be just an average temperature within the examined temperature region.

Ključne riječi

Hrčak ID:

137300

URI

https://hrcak.srce.hr/137300

Datum izdavanja:

15.10.1991.

Posjeta: 760 *