What does it mean when it's said that the positive terminal of a battery is at a higher potential than the negative end? How does electric potential (voltage) relate to electric current/electric fields?
That's exactly what it means. The cell is separate into 2 sides. For the perchloric acid and iron cell I mentioned, the perchloric acid is only on the positive side, and the iron is only on the negative side.What do you mean when you say “2 chemical half reactions”? Do you mean that there is a chemical reaction in each terminal?
It's based on how spontaneous the reaction is. Look at that table again, Fe 2+ is listed twice.How do the electrons know which is the positive and negative terminals?
The reactions can be reversed if you supply a voltage that is higher than the voltage the cell outputs. If a cell supplies 1 volt, you can reverse the reaction by supplying more than 1 volt to the cell.Also, how can the reactions be reversible? I thought that was only the case for rechargeable batteries?