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Define PH

Posted 18 mai 2012, 14:38 UTC−4 Low-Frequency Electromagnetics, Materials, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.2, Version 4.2a 2 Replies

Bahar
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Hi

Anyone has any idea how I can define PH of my solution in ACDC module?

Best
Bahar
2 Replies Last Post 22 mai 2012, 11:52 UTC−4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 18 mai 2012, 16:02 UTC−4
Hi

Interesting question, my first reply would be to take the concentration of H+ from the charge and call that the H+ activity (not strictly true but at least it is a first guess) and then take the log10 of the H+ activity to get the PH, and the units of pH are log(L/mol) Wiki found it back for me, hope its' right, mostly yes, but one never knows ;).

Some adjustments of the type of medium/solution and its composition must be used too (as the charge is for me the number of e- which is not necesarily the corresponding number of free H+)

Now, I must admit I havent done any serious chemistry for years, so this would need some serious and mandatory validation, as well as probably some corrections ;)

When checking quickly on Wiki it reminds me about the differential measurements used, by using electrodes potential measurements and calibration of these with known chemicals

But COMSOL has some excellent chemistry specialists, they should know, not to say all those using COMSOL for chemistry out there.

I'm eager to hear more ...

--
Good luck
Ivar
Hi Interesting question, my first reply would be to take the concentration of H+ from the charge and call that the H+ activity (not strictly true but at least it is a first guess) and then take the log10 of the H+ activity to get the PH, and the units of pH are log(L/mol) Wiki found it back for me, hope its' right, mostly yes, but one never knows ;). Some adjustments of the type of medium/solution and its composition must be used too (as the charge is for me the number of e- which is not necesarily the corresponding number of free H+) Now, I must admit I havent done any serious chemistry for years, so this would need some serious and mandatory validation, as well as probably some corrections ;) When checking quickly on Wiki it reminds me about the differential measurements used, by using electrodes potential measurements and calibration of these with known chemicals But COMSOL has some excellent chemistry specialists, they should know, not to say all those using COMSOL for chemistry out there. I'm eager to hear more ... -- Good luck Ivar
Bahar
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Posted: 1 decade ago 22 mai 2012, 11:52 UTC−4
Thanks for reply Ivar

I'm trying to model the PH by charge concentration since it was the first solution that came to my mind too. Still working on that...
But I also hope some people who are doing chemistry modeling can give us some idea too
Thanks for reply Ivar I'm trying to model the PH by charge concentration since it was the first solution that came to my mind too. Still working on that... But I also hope some people who are doing chemistry modeling can give us some idea too

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