Half-reactions

[Jasmine Botello 2F]

Are we always supposed to flip one of the half-reactions to give you the MOST positive E value?

[K Stefanescu 2I]

In most cases, yes. Just focus on flipping the reactions so you have the correct overall reaction equation (one half-reaction must be a reduction, the other an oxidation, and when added together, they must be equivalent to the original reaction).

[Kailey Brodeur 1J]

In addition to what was said above, make sure when you add the two half reactions together the electrons cancel out. This helps on the idea of flipping reactions because in one half reaction the electrons must be on the reactant side and in the other half reaction the electrons must be on the product side.

[Sirajbir Sodhi 2K]

This is only true in a GALVANIC CELL - where the chemical reaction is spontaneous. In an electrolytic cell, this is not what we would do (we'd actually do the opposite I'm quite sure), because the reaction is non-spontaneous.

[204932558]

Yes. Just make sure the electrons cancel out, and that the reaction with a more negative reduction potential is one being flipped.