How would you start these problems?

...I suppose this is a continuation from this post: (replace the numbers with id=1395127807)

But, I have yet figured out the ΔH ̊ and ΔS ̊ .
But once that is figured out, how would I start problem #1?
Also, for problem #2, could someone please explain to me why? Is it because Ca(OH)2 is not soluble in water and can only be collected through titration?

1. Calculate the molar solubility of Ca(OH)2at 50 ̊C using your experimental values of ΔH ̊ and ΔS ̊ . This value is not the average value of the molar solubilities at 0 ̊C and 100 ̊C solubilities? Why not?

2. Why is it necessary to filter the solution before titrating? How would having a small amount of Ca(OH)2(s) in the titration flask affect your results?