Please note that the question doesn't tell you if the solubility is to be done in moles/L or in gramsLL or some other units. The easy way is to solve in moles/L = M.
Here are two ways to do this. The long way and the short way. Here is the long way:
Look up the Ksp for each of the salts. Then calculate the solubility in M. I'll do one of them and leave the others for you.
......................BaSO4 ==> Ba^2+ + SO4^2-
I.......................solid............0...............0
C.......................solid...........s...............s
E.......................solid............s...............s
Then Ksp = (Ba^+)(SO4^2-) = 1.1E-10. That's the value in my text. Use the value in your text or your notes. Substitute the E line into the Ksp expression like this.
1.1E-10 = (s)(s) and solve for s = solubility = 1.05E-5 M. Do the other salts and arrange from low to high solubility. You are comparing the real solubility in moles/L.
The short way:
Look up Ksp for each of the salts. The smallest Ksp will be the salt with the smallest solubility in M and the largest Ksp will be the most soluble in M. You can explain how you determined which was the most and which the least soluble. But you must be VERY careful how you explain it BECAUSE the short way doesn't always work. You should explain that the solubility can be ranked this way BECAUSE each of the salts is a 1:1; i.e., 1 cation to 1 anion. If you had Mg(OH)2 or Cu2S (not 1:1 salts) you would need to do it the long way. You should also include a statement that if you determined the solubility in grams/L that it might be a different arrangement BECAUSE the molar masses are different. If you were in my class and you wanted to make a good impression you would do it three ways and rank with each; i.e., Do it the long way in moles/L, do it the short way in moles/L, do it both ways in g/L and compare each. And I would say, "This student knows this stuff."
Post your work if you get stuck.
Rank the solubilities (from least to most soluble) of PbS, CuCl, HgS, CaCO3, and BaSO4, and explain specifically how this ranking was determined. Make sure to include details about the magnitude of Ksp and what that indicates about solubility
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