If Ksp=2.1×10−33, what is the molar solubility of Ca3(PO4)2? Report your answer with the correct number of significant figures.

Question

If Ksp=2.1×10−33, what is the molar solubility of Ca3(PO4)2? Report your answer with the correct number of significant figures. 

Ca3(PO4)2(s)↽−−⇀3Ca2+(aq)+2PO3−4(aq)

Answer 1

I've done some of these before, so I'll get you started and you should be able to finish.

Ca₃(PO₄)₂(s) <===> 3Ca²⁺(aq) + 2PO₄^3-(aq)

Ksp = 2.1x10^-33 = [Ca²⁺]³[PO₄^3-]²

If you let x = [PO₄^3-] then [Ca²⁺] must be 1.5x because you get 3 Ca²⁺ for 2 PO₄^3- ions.

You now have 2.1x10^-33 = (1.5x)³(x)²

Solve for x to get molar solubility