How many moles of Calcium chloride can be added to 1.5L of 0.020potassium sulphate before a precipitate is expected? Assume that the volume is not chnaged significantly.

CaSO4 ==> Ca^+2 + SO4^=
Ksp = (Ca^+)(SO4^=) = ??. Look it up.
(SO4^=) = 0.02 M
Use Ksp to calculate (Ca^+2).
The answer will be the concentration in mols/L. Calculate how many mols that will be in 1.5 L.
Post your work if you get stuck.

2 answers

0.0018 moles of calcium chloride
0.00375 moles