ISSN:
1572-8927
Keywords:
Equilibrium constant
;
enthalpy change
;
entropy change
;
heat capacity change
;
flow calorimetry
;
high temperature
;
magnesium chloride
;
calcium chloride
;
hydrochloric acid
;
ion association
;
isocoulombic reaction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The aqueous reactions, Mg2++Cl−=MgCl+, Ca2++Cl−=CaCl+, and H+ +Cl−=HCl(aq), were studied as a function of ionic strength at 250, 275, 300, and 325°C using a flow calorimetric technique. The logK, ΔH, ΔS and ΔCp values were determined from the fits of the calculated and experimental heast. The data were reduced assuming a known functionality of the activity coefficient. Hence, the logK, ΔH, ΔS and ΔCp values determined in this study are dependent on the activity coefficient model used. These thermodynamic values were compared with literature results. The logK values for the formation of MgCl+ agree reasonably well with those reported in the literature. The logK values for CaCl+ formation agree reasonably well with those reported in the literature at 300 and 325°C. At lower temperatures, the agreement is poorer. The logK values for the formation of HCl(aq) are generally lower than those reported in the literature. The logK, ΔH, ΔS and ΔCp values for all three ion association reactions are positive and increase with temperature over the temperature range studied. These values are the first determined calorimetrically for the formation of MgCl+ and CaCl+ in the temperature range 275–325°C.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00651508
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