[NewtoAtoms]

Hello Chemists,

I once again have finished Chapter 16, solubility equilibria chapter in my text, and have stumbled across a perplexing problem, and hoping someone can help me walk through. Unfortunately my chemistry teacher doesn't speak English so us students are left to our own devices to learn this stuff. 

Q:  Using the Ksp values given, find the solubility in mol/L of Calcium Phosphate in water.

A:  I have done the following work, and I am wondering if someone can review it with me and aid me on the issues?

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

Ksp = [Ca]³ [PO₄]²

                     Ca                       PO4
Initial               O                         O
Change            +3s                       +2s
Equilibrium        3s                          2s

Ksp = [3s]³ [2s]² = (27s³)(4s²) = 108 s⁵

Ksp for this particular reaction is 1.2 x 10^-26 therefore

1.2 x 10^-26 = 108 s⁵ (divide both sides by 108)
1.11 x 10^-28 = s⁵  (fifth root each side)
gives the answer. 

The problem is that I am not even sure if I have done this correct, before I try to venture out and try to learn if there is actually something called a fifth root.

I would greatly appreciate anyone's help and guidance.

Thank you!

[AWK]

OK

[NewtoAtoms]

OK?  Does that mean I have done this correctly and am understanding?

Thank you for your time.