 Okay, let's try this one here. So this, first of all, it says calcium iodide, we don't know the physical state, plus sodium phosphate, we don't know the physical state. We want to know, we want to eventually write the molecular, the total ionic and net equations, identifying, also identifying the spectator ions. In order to do that, we need to do a few more things to analyze this equation. Like first, the thing we need to do is balance the equation and figure out what our products are going to be, okay? So the first thing we need to do, remember, on these types of problems is to identify, you know, what's going to precipitate out with anything, okay? So calcium iodide, sodium phosphate, and then what would be the other things? Well, it would be calcium phosphate and sodium iodide, right? So sodium iodide is going to be NaI, right, because I is normally minus one and Na is plus one. And the other thing is going to be calcium phosphate, okay? That's the harder one to figure out what the equation should be, or the molecular, the chemical formula should be. So how do we figure this out? Well, we know that calcium has the what charge plus two, right? Everybody should know that by now. It has a plus two charge. And phosphate, well, even if you didn't know, yeah, it's going to be a negative three, but even if you didn't know, you could look at this compound here and it gives you, it tells you what it is, right? Since sodium is plus one and there's three plus ones, you want the whole thing to equal zero, it's got to be negative three, okay? So now we've got to figure out a way to combine a negative three ion with a positive two ion, okay? So the way you want to always be able to do this or think about doing this is to find what we call the common factor of the two, okay? In this case, it's going to be six, right? You can think of it that way and you can add these up to six, each one of them to six if you want to do that. Or you can just think of them, okay, how many plus twos do I need to get to plus three? Okay, that's a, well, they don't go one to one together, so we've got to figure something else out. So let's write another CA two plus. Can I do four, because two plus two is four, can we get that to three? No, right? Well, let's try this. We'll put another PO four, three minus. Well, we've got six over here now. Can we get six to four? No, but if we add another calcium, right? That gives us an overall six here, overall six there, right? Does that make sense? That's the way you always want to do it, okay? So now we say, okay, well, how many calcium do I have? Three of them, right? So we've got three CA two plus, and how many phosphates? Two, two PO four, three minuses, okay? So let's erase all of this work. So now, we don't write compounds like this, we kind of combine everything together. So this compound is going to be CA three, PO four, two, like that, okay? Because why? Because we have three calciums and two PO fours. Now we've got to ask ourselves, well, what's the physical state of these things, okay? Well, we've got to remember our physical state rules, whether something precipitates or not, okay? So it says here, for calcium iodide, it says all common chlorides, bromides and iodides are soluble, except for silver, lead, copper, and mercury. So that's an iodide, calcium iodide is an iodide, and it's not combined with silver, lead, copper, or mercury, right? It's combined with calcium, so we know this has to be aqueous. Also, we look over here, and we see that all common group 1A ions, lithium, sodium, potassium, and ammonium ion are soluble, right? So in that case, we say, well, this is a sodium one, right? It's got to be soluble. This is a sodium one, it's soluble. This is also an iodide, so it's soluble, doubly soluble from our rules. And what about phosphates? Well, all common carbonates, phosphates, and are insoluble. All common carbonates, phosphates are insoluble, except those of group 1A and ammonia. Well, this is a phosphate, but it's paired with a group 1A, okay? This is a phosphate, is that a group 1A? No, so it's going to be insoluble, okay? Or a solid. Okay, so now that we figured that out, right? Let's go ahead and put the equation together before it's balanced, okay? So we've got AQ there, AQ there, CA3PO4 solid, right, plus NAI AQ, okay? So is everybody cool with that? So erase this work down here, and erase this over here just so we don't confuse ourselves. Okay, now we need to balance the equation, okay? So let's look at this equation. We see we've got calcium over here, we've only got 1, but we've got 3 over here, okay? So we need to put a 3 in front here. Just here, we've got 3 sodiums and only 1 sodium over there, right? But also, we've got 6 iodide, right? And we've only got 1 iodide over there. So in order to get 6, we're going to have to put a 6 in front of that thing. So our calciums are balanced, our iodides are balanced, right? Now let's look at our sodium. Here we have 6 sodium. Here we have only 3 sodium. This should be a 2 anyway, sorry. Yeah, if we put a 2 there, right, then we've got 6 sodiums, okay? So we've got 3 calciums, 6 iodide, 6 sodium. 3 calciums, 6 iodide, 6 sodium. How many phosphates do we have here? 2. How many phosphates do we have here? 2. Okay? So our equation is balanced. Yeah, it's about to be a double replacement reaction, okay? So now we've ridden the molecular equation. Let's write the total ionic equation. I fully expect you guys to be able to do this on your own by now. So what I'll let you guys do is try to do it on your own while I'm doing it up here, okay? So remember, everything that says aqueous break apart. So in this case, we've got 3 calciums, we've got to put aqueous, 3 times 2 iodide, 3 times 2 is 6, I minus aqueous. Then we move on to sodium phosphate. 2 times 3, 6 sodiums, aqueous, phosphate, right? How many do we have? 2 phosphates, aqueous, okay? So those are all our reactants. Let's write our products. Calcium phosphate, it's a solid, we don't break it up, right? And sodium iodide, aqueous, so we break it up. 6 sodiums plus 6 iodide, aqueous. So that's our total ionic equation. Now let's go back and figure out what our net ionic equation is and our spectator ions. So remember, with the net ionic equation, what did we do? We looked at both sides, saw what was the same on both sides, and cancelled those things out. Calcium, not the same on both sides. Iodide ion, same on both sides, and we have the same amount, 6, so we're going to cancel that out. 6 NA pluses on this side, 6 NA pluses on that side, cancel out. All the rest is different from both sides, right? So we're going to write our net ionic equation as 3CA2 plus aqueous plus 2PO4 3 minus aqueous goes to CA3PO4 2. Sorry, I keep missing that up. So that's the net ionic equation there. And then if I asked you what are the spectator ions, what would you say? 6 I minus and 6 NA plus. You know, honestly, if you would have just said, if I just asked for spectator ions and you just put I minus and NA plus, that'd be fine. Any questions on this? Pretty straightforward, huh? So this is everything that we learned today, and in the last couple of days as a matter of fact.