 Okay, finding ions in a solution, sorry, I pushed your cord, so you told us what we were doing. So we're figuring out the number of moles of ions in this solution. Okay, so the last one we did was molarity of ions. Now we're going to do moles of ions. Okay, so what is the number of moles of ions total in 26.9 microliters of a sodium sulfate solution? That's 0.38 formal. Okay, so the first thing we need to do is remember that chemical equation. So Na2SO4-solid, when we dissolve it into water, breaks up into Na plus Equus plus SO4. Okay, so remember when we figured this out last time that since there's two sodium ions in one sulfate ion and it wants the total number of ions we can effectively say there's three ions on this side of the equation. So we have a mole to mole ratio 1 to 3 when we're relating sodium sulfate to the number of ions. Okay, so let's figure out first what the molarity of the ions is. Okay, and it's the same thing that we did last time, but let's just write it out formally. So moles of sodium sulfate, one liter of solution. So we have one mole of sodium sulfate or three moles of ions that's going to cancel with that. So let's just do this calculation again. I do it again since it's still written here on the calculator. 1.15 and we can say moles of ions per one liter. So we don't have to convert this to molare back to just capital N. Because actually what we're going to do is use this volume to cancel this volume. Okay, so it says that we have a volume of solution of 26.9 microliters. So for every liter of solution we have 1.15 moles of ions. So what we do is just multiply this. So we got to convert microliters to liters. So what did we say? It was 1 times 10 to the sixth microliter per one liter. Like that. And then all we have to do is just move that down there, cancel up liters. 1.15 moles of ions per one liter of solution. So cancel there, cancel there, cancel there, cancel there. And hopefully you can see from all of that we should get our moles of ions as our final answer. This is a six. So if we were doing it the other way. So you want to think microliters are smaller than liters. So that's going to be a positive. So if you were going from bigger to smaller then it would be a negative. So let's just do this. So what I got is 3.10 times 10 to the negative fifth moles of ions. And 26.9 microliters of .384 moles of sodium sulfate solution. So that makes sense to everybody. Again, recall this is just more conversions, right? So that's what we're doing is just piling conversions on top of conversions on top of conversions. So if you are ever in doubt, try to cancel out units to get a unit that makes sense for the final answer of the problem. Are there any questions about this one?