Write the expression for the solubility product constant of MgF2 (see Problem 4.139). If [Mg2+] = 2.6 * 10-4 mol/L in a solution, what is the value of Ksp?

Video transcript

hi everyone for this problem. It reads provide the cell viability. Product constant expression for ammonium per chlorate. What is the solid ability product constant value If ammonium and the solution is 1.85 molar. So we have two things we want to answer here. The first is the soluble itty product constant expression and the second is the solid ability product constant value. Okay, so in order for us to solve for the solid ability product constant expression. Let's go ahead and create an ice table for the reaction. So we're going to go ahead and write out our reaction. So we have ammonium Perk Lowrie. And this is a solid and our our reaction is at equilibrium and we have ammonium and okay, so when we create an ice table we write out the initial concentration, the change in concentration and the equilibrium. Okay, now let's just recall that in an ice table as well as the equilibrium expression solids are not included. And because ammonium per chlorate is a solid, we're going to ignore this. Okay, so in terms of our products, we have zero products. So we'll go ahead and put zero as the initial concentration for the products. What that means is our reaction is moving in the forward direction. And so the change in concentration for the reactant is going to decrease and the change in concentration of products is going to increase. So this change now becomes plus X and plus X. Because we only have one mole of each. So for the equilibrium row this becomes X. And this becomes X. Okay, so now we can write out the scalability product constant expression, the solid ability product constant expression is the concentration of products over the concentration of reactant. And for the for the expression the ammonium per chlorate is the solid. And because of that it's not going to be included in this expression. So what this expression becomes then is just the concentration of products. And if we were writing this accurately this would be over one. Okay, because we are not including the concentration of reactant since it's a solid. So that means then our final solid ability product constant expression is going to equal the concentration of products and that's it. Let me write that more clearly. So this is what it's going to look like. Okay, so we can go ahead and highlight that as our final answer for the solid ability product constant expression. Now we're being asked to solve for the scalability product constant value if ammonium and the solution is 1.85 moller. Okay, so taking a look at our ice table, we see that the that X. So we see here we have two X. S. And X. Is going to equal the concentration of ammonium and it's also going to equal the concentration of the quarry. Alright, so that means our X. Is equal to and we're told in the problem 1.85. So X. is equal to both the concentration Of the products. It's the same thing for both. And we know what that value is. It's 1.85 moller. Okay, so if we solve four are solid ability product, it's going to equal the concentration of 1.85 Times 1.85 because we're plugging an X. There. So what we get then for the value is the value is going to equal 3.42. Okay, so that is our final answer. So that is the value for the cell viability product constant. And we also wrote the solid E ability product constant expression. So that is it for this problem? I hope this was helpful.