 Okay, so let's try to calculate an unknown half cell potential from the potential of the entire cell. So a voltaic cell houses a reaction between aqueous bromine and zinc metal given to you up there in that balanced equation. Okay, the standard cell potential is 1.83 volts. Let's calculate the standard potential of bromine given that the potential for zinc is negative 0.76 volts. Okay, so if you recall, the standard potential of the cell equals the standard potential of the cap of minus the standard potential of the end. So in order to figure out what's what, we need to break this thing into its half reactions. So we've got, this is going to be the standard potential, and here we're going to have to add those two electrons, so now our charge is gone. So this one, well we would expect the electrons to be over here. So with bromine being reduced, right, that's going to be the potential of the cap of. So the thing at the cap of is the thing that gets reduced. So we could say this is going to be equivalent to the standard potential of the cap of. So that must mean this is the standard potential at the end. So let's just use half reactions down here. So the only reason I did that is to figure out which one was the cap of and which one was the end. So we know E cell, we know E zinc, but we don't know any bromine. That's what we're looking for, so let's rearrange this to find E zinc. So that's one of the seven. Okay, is everybody okay with doing something like that? So problems are getting easier.