 Lead 2 sulfate solubility in water at 25 degrees Celsius is 4.25 times 10 to the negative 3 grams per 100 milliliters. What is the KSP of lead 2 sulfate? Okay, so in order to do a problem like this you're going to have to know what lead is, sulfate is, and how to combine these things. So let's go ahead and write lead 2 sulfate, so like that. So you also know that this is a slightly soluble compound, so you can write a reaction equation. So we know the KSP of this thing, E2 plus. So the solubility is given in grams per 100 milliliters, so that's the solubility of that. And we have a 1 to 1 to 1 ratio of these things, then it has to be the solubility of this thing and of this thing too. So, but we use these units, we take these things to molarity units in the KSP equation. So this up here is not in molarity units, so we're going to have to change those to molarity units, okay? So how do we do that? We're having 1,000 mills is 1 liter. Okay, if we do that, the units of molarity are what? Moles per liter, so do we have moles per liter here? No, we have grams per liter, right? So in order to get moles, we're going to have to use the molar mass, right? So if we had a lead sulfate, it should be 303.3 grams per mole. Okay, so let me do that, cancel, cancel, 4.25, 1.40 times 10, the negative 4. Okay, so that's the solubility in molar quantities, so molar to molar to molar, right? So we've got a 1 to 1 to 1 ratio there and we're looking for the KSP, the value of it. Well KSP equals the concentration of lead 2 times the concentration of sulfate. So this is 1.40 times 10 to the negative 4th molar, then this must be 2 and this must be 2. So in order to do this, 1.40 times 10 to the negative 4th, and I'm not going to put any units in to not confuse myself, 1.96 times 10, 8. Questions on that?