### finding n

Posted:

**Sun Mar 01, 2020 2:34 pm**How do you find n from an equation for a reaction?

Created by Dr. Laurence Lavelle

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

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=141&t=60756

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Posted: **Sun Mar 01, 2020 2:34 pm**

How do you find n from an equation for a reaction?

Posted: **Sun Mar 01, 2020 2:37 pm**

Since n is the number of electrons transferred you can look at the charges of the atoms in the reactions and see what is changing. More directly, by writing out the half reaction and balancing it to see how many are transferred since the number of electrons has has to cancel that is the number transferred.

Posted: **Sun Mar 01, 2020 2:43 pm**

Clarice Chui 2C wrote:How do you find n from an equation for a reaction?

n is the total number of electrons that's being transferred from the anode to the cathode, which you can find after balancing the two half reactions. In the equation ΔG = -nFE, n is in mol e-/mol rxn. For example, if an equation had a total of 2 e- transferred from anode to cathode, then n would be 2 mol e-/mol rxn

Posted: **Sun Mar 01, 2020 4:08 pm**

n stands for the number of electrons transferred. You find this value by balancing the two half reactions in a redox situation. Once you balance them, you look at the electron transfer and use that value as n.

Posted: **Sun Mar 01, 2020 4:41 pm**

What happens if the number of electrons transferred is different? Do you have to balance the equation to make it the same?

Posted: **Sun Mar 01, 2020 4:43 pm**

Clarice Chui 2C wrote:How do you find n from an equation for a reaction?

To find n for a reaction, write out the individual oxidation and reduction reactions. To balance the reaction, you have to include electrons to balance out the reaction. n correlates to this number of electrons.

Posted: **Sun Mar 01, 2020 4:56 pm**

Adriana_4F wrote:What happens if the number of electrons transferred is different? Do you have to balance the equation to make it the same?

Yes, you would have to balance the half-reactions so that the number of electrons transferred is the same.