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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: fsonnichsen on June 20, 2019, 01:37:04 PM

Title: Time for dissolved IONs to migrate in a field.
Post by: fsonnichsen on June 20, 2019, 01:37:04 PM

I am trying to calculate some speeds for the migration of ions in solution under and electrical field. I have values of ionic mobilities for K+ for example of:
   u=7.62E-8 (m**2/sV)
Take a typical voltage of 1.0 for plates separated by 1cm:
  E=V/D = 1V/0.01m = 100(V/m)
Using:
   speed(m/s) = u E
we have:
   s=7.62E-8 x 100 = 7.62E-6 m/s = 7.62E-4 cm/s
To transverse the 1cm plates it would take
1/7.62E-4 = 1300 s or 20 minutes.

Seemed high-Does this sound reasonable?---I guess my intuition is weak here and I found no worked problems in the texts I have!
thanks
Fritz

Title: Re: Time for dissolved IONs to migrate in a field.
Post by: Enthalpy on June 21, 2019, 09:28:43 AM

OK.