cell potential

[Ruiting Jia 4D]

For getting an E(total) from two reactions, how do we know when to add and when to subtract? I always thought we needed to do Ecathode - Eanode ...

[Samantha Pacheco 2K]

If you reverse a half reaction and you do not change sign of E° then we use that equation Ecathode-Eanode, you will always subtract . If you do flip the sign of the E° in the reaction you reversed then you would add the 2 cell potentials.

[Karan Thaker 2L]

To do E cath - E anode = E cell, always keep the reaction in reduction form... if you reverse anything, you have to add.

[eden tefera 2B]

I find it more straightforward to do Ecathode- Eanode rather than reversing Ecell because sometimes the reduction potential is negative and it can get confusing.