 Okay. So this question says, when a student mixed aqueous solution of calcium iodide, so let's just write down calcium iodide, okay? So you know it's going to be CaI2, right? Because calcium's oxidation state is plus 2 and iodine's is minus 1, okay? So you know it's going to be CaI2. You know that the state is going to be AQ because it says a student mixed an aqueous solution, okay? So then it says also with an aqueous solution of potassium sulfate, okay? So potassium, well, so remember potassium, potassium is a plus 1, right? Sulfate, SO4, you got to remember, SO4, it's 2 minus, okay? So it's going to take two of these guys for every one of these, so it's going to be CaI2SO4 and since it says aqueous solution, it's going to be aqueous. So now it says a precipitate was formed, okay? So you know something's happened here. You should know that solutions are aqueous solutions of potassium ions don't form precipitates, okay? And iodide only forms precipitates with silver, okay? So in mercury, too. But so if you know that, then you should know that the precipitate is calcium sulfate because these are always double displacement reactions, these precipitate reactions. So remember a double displacement reaction is where this guy comes over and bumps this guy out and this guy, well, this guy steals that one, okay? So it's going to be kind of, so you can think of it like stealing that one, this guy stealing that one, yeah, doing the kind of docy-dough or switching, yeah. Okay, so in that case, what are we going to get? We got Ca2 and I2, but Ca is plus 1 and I is plus 1. So it's going to be Ki2Ki, okay? Because the compound is potassium iodide, Ki. You know that doesn't form a precipitate, so it's going to be aqueous because all solutions of potassium ions don't form precipitates. But calcium sulfate, you should know calcium likes to precipitate things, okay? So calcium is a big one that precipitates mercury, silver, okay, lead sometimes. Those are the ones you want to remember. In this case, calcium is 2 plus, remember, and sulfate is 2 minus, so they're just going to, they're made for each other. They just stick together like that, okay? But they're going to be precipitate, so it's going to be solid there. So that reaction there that you just wrote, that's called the molecular equation. Now we're going to write the total ionic equation, okay? So whenever you see for the total ionic equation, whatever it says aqueous, that means break it up into its ions, okay? Calcium ion Ca2 plus. It's got an aqueous there, you've got to put it behind each thing because you're breaking these up into their ions. There's no ion I minus, I mean sorry, I2 2 minus. It's going to be 2 I minus, like that, aqueous. And you come over here, calcium or potassium, there's no K2 2 plus ion. It's 2K plus ion, aqueous, plus the sulfate SO4 2 minus aqueous and 2K's aqueous plus 2I's aqueous plus, notice here it's not aqueous, so we just plop that thing right there. CaSO4 solid. Okay, that's the total ionic equation. Why is it the total ionic? Because it totally tells you every ion that's in that equation. Now let's do the net ionic equation. Net, just like what's your net salary, right? It's whatever you get after you take everything else out, right? Okay, so how do you take things out? Just like an algebraic equation, right? So just like an algebraic, let's just go to an aside for a second, right? How do we solve this problem? X minus 3 equals 2, right? We add 3 to both sides, right? So it's kind of like that. Or if you got X minus 2 equals minus 2, right? If you add 2 to both sides, right, it's X equals 0. It's kind of like that. You just kind of are canceling out what's on both sides, okay? So here we look, do we have Ca2 plus on both sides? Well, we got Ca2 plus over there. We got Ca over here, CaSO4, but that's not Ca2 plus, okay? So that has to stay in the reaction. 2i minus on the other hand, if we look here and we look over here, they're both there, right? So we can cancel those guys out. Same thing with our 2k pluses. Cancel those guys out. Now the sulfate, there's no SO4 2 minus aqueous on the other side, right? So we can't do that. What we got now is our net ionic Ca2 plus aqueous plus SO4 2 minus aqueous goes to CaSO4 solid, okay? That's the net ionic equation. And then I think the last thing it says, clearly indicate the spectator ions. I would prefer, I guess I would accept grudgingly that you just crossed those out and that's the spectator ions. I would prefer you said spectator, right, and said you don't have to put 2. Just k plus and i minus. So the spectators are the things that don't participate in the reaction. Are there any questions on this? Does that make sense? Okay. I promise you it should, you know. So just keep working it, working it, working it. Now go back to those ones that, you know, before that maybe try to listen to them and do it on your own with me talking to you, okay? So are there any questions before I shut down the video? Okay, cool.