ISSN:
1572-8927
Keywords:
Ternary diffusion
;
densities
;
NaCl−KCl−H2O
;
Gouy and Rayleigh interferometry
;
concentration dependence
;
comparison of methods
;
comparison of apparatus
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Diffusion was systematically studied in the ternary system NaCl (0.5M)−KCl (0.5M)−H2O at 25°C. There were four purposes. First, current methods to extractD ij from Gouy and Rayleigh interferometry data depend on treating theD ij as effectively constant. If concentration differences ΔC i across the boundary are large, this may not be true. To explore this issue, four sets of experiments were performed. Each set had four experiments with approximately the same total number of fringesJ. Each set also had the same corresponding ΔC 1/ΔC 2 ratios as the other three, but the ΔC i were adjusted such that the four sets hadJ≈30, 60, 90, and 120, respectively. Noclear dependence of theD ij on ΔC i was found within their realistic errors. Second, the Gosting diffusiometer can yield both Rayleigh and Gouy fringe patterns during the same experiment. Therefore, theD ij from both methods were compared, and agree well. Third, a new method for analyzing Gouy fringe positions (Miller; program TNY) can be compared to the classical one (Fujita-Gosting; program RFG). TheD ij from both analyses agree well. Fourth, we compared results from the Gosting diffusiometer with those at the same composition from other diffusiometers: one data set by O[Donnell and Gosting from an older Gouy apparatus, and three Rayleigh sets at differentJ values from our older Model H diffusiometer. Results from older diffusiometers were more scattered, but correspondingD ij agree within realistic errors. As reported previously, realistic errors are approximately four times the statistical errors obtained by least squares. Recommended Rayleigh and GouyD ij are presented for this composition.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00972646
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