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
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.
To rank the solubilities of PbS, CuCl, HgS, CaCO3, and BaSO4 from least to most soluble, we need to consider their respective solubility products (Ksp) values. The relative magnitudes of Ksp indicate the solubility of a compound: the smaller the Ksp, the less soluble the compound, and vice versa.
1. PbS (lead(II) sulfide):
PbS has a small Ksp, indicating low solubility. Its Ksp is approximately 7.6 x 10^(-29) mol^2/L^2. This means that only a small amount of PbS will dissolve in water, making it the least soluble compound in this group.
2. HgS (mercury(II) sulfide):
HgS has a slightly higher Ksp than PbS but is still quite small. Its Ksp is approximately 1.6 x 10^(-54) mol^2/L^2. Although HgS is slightly more soluble than PbS, it is still considered highly insoluble.
3. BaSO4 (barium sulfate):
BaSO4 is less soluble than both PbS and HgS but more soluble than CaCO3. It has a Ksp of approximately 1.1 x 10^(-10) mol^2/L^2. BaSO4 is considered sparingly soluble, meaning only a small fraction of it will dissolve in water.
4. CuCl (copper(I) chloride):
CuCl has a higher solubility compared to PbS, HgS, and BaSO4. Its Ksp is approximately 1.0 x 10^(-6) mol^2/L^2. CuCl is considered moderately soluble, with a larger fraction dissolving in water compared to the previously mentioned compounds.
5. CaCO3 (calcium carbonate):
CaCO3 is the most soluble compound among the given options. Its Ksp is approximately 4.8 x 10^(-9) mol^2/L^2. Although CaCO3 has a larger Ksp than BaSO4, it is still considered relatively insoluble. However, compared to the other compounds on the list, CaCO3 is the most soluble.
In summary, the ranking from least to most soluble is: PbS < HgS < BaSO4 < CuCl < CaCO3. This ranking is determined by comparing the magnitude of their respective Ksp values, where compounds with smaller Ksp values are less soluble and those with larger Ksp values are more soluble.