Calculating standard cell potentials

[ZoeHahn1J]

When calculating the standard cell potential of a reaction, do we always flip the oxidation half reaction? I know that for galvanic cells, Ecell has to be greater than zero, so we flip the larger value, but I'm not sure about non-galvanic cells.

[Tasnia Haider 1E]

You want E to be positive because the reaction has to be spontaneous which only happens in galvanic cells. So, I believe that you have to flip the oxidation side if you are using that method of calculating E.

[ZoeHahn1J]

Right, but would there ever be a time when standard E is negative for a not galvanic cell, or when we would have to flip the reduction rxn for a galvanic cell?