 Okay, so let's try this particular problem. This is another electroplating problem, so this one says, if a constant current of 5.0 amperes is passed through a cell containing the chromium 3 plus ion for 1.0 hours, how many grams of chromium will plate out on the cathode? Okay, so, well, you can do this problem a number of different ways, but let's start with, it says that we've got a solution of Cr3 plus aqueous. Okay, and if we're going to run a current through this, that means we're going to add some amount of electrons to get it to Cr solid. Okay, so to go from a plus 3 oxidation state to a zero oxidation state, we're going to have to use three moles of electrons for every one mole of the chromium 3 plus cathode. Is everybody okay with that? Yeah. Okay, the other thing, well, there's a couple of other things you've got to remember. Let's write them down. So one of them is 1 coulomb is equal to 1 amp second, okay? So that kind of gives us a clue as to what we have to do here with our hours. We're going to have to convert that into seconds, and we'll do that later on. The other thing we know is that 1 faraday equals 96485 coulombs per mole of electrons. Okay, so that's going to come in handy as well. That constant or that conversion factor will be given to you. So is everybody okay with what we've done so far? Yes. Okay, wonderful. So the first equation of this you want to recall is going to be this one. i equals q over t, or current equals charge divided by time. Okay, so we have the time and we have the current, but we don't have the charge. So let's rearrange this equation and solve for that. Okay, so charge is going to be equal to current times time, right? Charge equals current times time. But that time has to be in seconds. So let's go ahead and do this. So we've got 5.0, 1.0 hours for our time, but we want to convert that to seconds. Okay, so when we convert that to seconds, we're going to say for every 1 hour, 3600 seconds. So there's 3600 seconds in our now. So cancel, cancel. So now we have amp seconds, right? That's what we're looking for. Okay, so 5 times 3600 is going to be 1.8 times 10 to the fourth coulombs. So is everybody cool up to that point? Yes. Okay. So now we want to figure out well what is the number of moles of electrons that this amount of charge correlates to? Okay. Why do we need that? Because we figure out the number of moles of electrons, right? We can use this chemical equation and figure out the number of moles of chromium. From there, figure out the mass of chromium. Okay. So in order to figure out the number of moles of electrons, right, we can use that number and couple it with for every this many coulombs, that's a mole of electrons, right? So we've got 1.8 times 10 to the fourth coulombs. So for every one mole of electrons, we've got 96485 coulombs. So those cancel like that. And I give the number 0.187 moles of electrons. Okay. Are we good to that point? Yes. So would anybody mind if I erase this top part so I can use? Are we good at that? Yes. We've got 0.187 moles of electrons. And we want to know, well, what's the number of moles? Well, let's go all the way to the mass of chromium. Okay. So isn't that what we're trying to figure out? Yeah, how many grams of chromium we'll play. So we're trying to figure out the mass of chromium. And we know the number of moles of electrons, 0.187 moles of electrons, right? But for every three moles of electrons, we make one mole of chromium, right? Is everybody okay with that one? Okay, so let's convert that. So three moles of electron, one mole of chromium. Okay, but that, there, that's moles of chromium. That's not grams of chromium. So what do we need to use? So on the bottom here, we're going to cancel out moles of chromium and get grams. So what do we use the molar mass, right? So 52.00 grams of chromium. Okay, that's the molar mass of chromium. So when we do this, we get grams of chromium. And that's what the problem wanted, right? Mass of chromium in grams. So we take 0.187 divided by three, multiplied by 52, and we better get the right answer. So to three safe things, right? Yeah, 2.3, or sorry, 2.23. 3.23 grams of 3.23. Yeah, that's what I get for this. It's my dyslexia. Any questions on that one? Okay, wonderful.