### Relationship Between Ecell and K

Posted:

**Tue Mar 03, 2020 10:50 pm**what's the relationship between Ecell and the value of K? (i.e. if K > 1 or K <1)

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=140&t=61248

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Posted: **Tue Mar 03, 2020 10:50 pm**

what's the relationship between Ecell and the value of K? (i.e. if K > 1 or K <1)

Posted: **Tue Mar 03, 2020 11:32 pm**

I think the higher the value of K, the higher the value of Ecell.

Posted: **Mon Mar 09, 2020 1:46 pm**

If E˚ is positive, then K>1; if E˚ is negative, then K<1. This will always hold true. It may also be important to note that whenever E˚ is positive, then ∆G˚ is negative, and vise versa.

Posted: **Mon Mar 09, 2020 1:48 pm**

When Ecell > 0, then K>1.

When Ecell < 0, then K<1

When Ecell < 0, then K<1

Posted: **Mon Mar 09, 2020 2:08 pm**

K is greater than 1 if Ecell is greater than 0. K is less than 1 if Ecell is less than 0

Posted: **Wed Mar 11, 2020 10:44 am**

I agree with all the previous responses, and it makes sense if you think about the meaning of these values. Ecell can describe spontaneity (spontaneous if the value is positive, not spontaneous if the value is negative) while K, the equilibrium constant, describes whether the reaction is product or reactant favored. We can see that spontaneous reactions will have more product (Ecell>0 and K>1) while nonspontaneous reactions will have more reactants (Ecell<0 and K<1).

Posted: **Wed Mar 11, 2020 4:59 pm**

Ecell and K are positively related so the larger the K means a more positive Ecell

Posted: **Wed Mar 11, 2020 5:09 pm**

Looking at the two equations E˚= (RT/nF)lnK and Ecell = E˚- (RT/nF)lnQ, you can see that if K>1 then E˚> 0. When E˚>0, then Ecell will be a greater value and will most likely be greater than zero as well. So if K>0 then E˚>0 and Ecell>0.

Posted: **Wed Mar 11, 2020 10:36 pm**

I remember my TA writing Ecell>0 than K>0 and vice versa, and you can prove this from the equations

Posted: **Thu Mar 12, 2020 2:08 pm**

Ecell and K are positively related