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Analytical expression for the temperature dependence of log K
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Topic: Analytical expression for the temperature dependence of log K (Read 409 times)
Alexey
Frequent Contributor
Posts: 16
Analytical expression for the temperature dependence of log K
«
on:
September 29, 2017, 04:31:20 PM »
Probably this is a very basic question, but I didn't find its consideration through the forum. PHREEQC uses the expression log K = a + b*T + c/T +d*log10(T) + e/(T^2) to calculate the temperature dependence of log K. What is a standard approach to calculate a, b, c, d, and e, if I know T and log K? I can apply the linear regression in SPSS STATISTICS, but this software ignores c and d because they are highly correlated with other factors. The form of a, b, 0, 0, e provides pretty good results, but probably there is another, more correct way to calculate them.
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dlparkhurst
Top Contributor
Posts: 1210
Re: Analytical expression for the temperature dependence of log K
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September 29, 2017, 05:00:56 PM »
If the statistics indicate correlation and the fit is as good, I would leave some of the parameters as zero. You will note that many of the analytical expressions do not use all of the parameters.
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Analytical expression for the temperature dependence of log K