This thread does my heart good to see. Looks like
nonsensical is wearing out the e-chem quite nicely - well done sir, well done.
ghoast: are you comfortable working with balancing equations that don't involve electron transfer? if so, then think about these reactions as being very similar to those reactions, with the main difference being that these have an extra reactant or product: namely electricity. As
non has put forth, you've got 'half-reactions' and each one of these half-reactions takes a certain number of moles of electrons in order to go to completion. You can look up the standard form of the half-reactions in Tables from many chemistry books - hopefully yours has one in the Appendix somewhere. One of the reactions will require a certain number of electrons to be pumped into it, and one of them will release a certain number of electrons. These are reductions and oxidations, and they are paired through mass conservation, as well as the conservation of electrical charge.
I don't know if that helps explain where
non's numbers are coming from or not, but I'll be happy to fuck up an explanation of it more thoroughly if you like
Good luck with the homework.