Oxidizing and Reducing

[Andrea_Torres]

How do we know which one is being oxidized or reduced if they both look like they both received the same amount of electrons in half reactions?

[Jason Wu 1E]

I think the half-reaction when written in the form of reduction and has the most positive cell potential, will be placed at the Cathode to be Reduced. Thus the other reaction which is either negative or less than the reduction reaction will be flipped, placed at the Anode and then oxidized. In summary, Cell potential determines which reaction is oxidized and which is reduced!

[preyasikumar_2L]

Since the half-reactions are typically written as reduction reactions, you have to use the cell potentials to understand which one is being oxidized and which one is being reduced.
More positive - reduction, cathode
More negative - oxidation, anode

[Owen-Koetters-4I]

the more positive potential is the reduction half reaction and the more negative is the oxidation reaction

[Jessica Booth 2F]

It depends on the situation that is being set up. If the cell is a galvanic cell then the half-reaction with the more negative potential will be oxidized and the half-reaction with the more positive potential will be reduced. If the set-up is for electrolysis, then the more negative potential will be reduced and the more positive potential will be oxidized.

[J_CHEN 4I]

Use the equation Ecell = E(cathode) - E(anode). Plug the cell potentials of the half-reactions so that Ecell > 0. When Ecell > 0, then you know what the reduction and oxidation half-reactions are by looking at the equation.