Hydroxyapatite, Ca10(PO4)6(OH)2Ca10(PO4)6(OH)2 , has a solubility constant of Ksp = 2.34×10−592.34×10−59 , and dissociates according to

Ca10(PO4)6(OH)2(s) --> 10Ca2+(aq) + 6PO4^3-(aq) + 2OH-(aq)

Solid hydroxyapatite is dissolved in water to form a saturated solution. What is the concentration of Ca2+ in this solution if [OH−] is fixed at 2.80×10−6 M?

I tried the question and got 3.99, but my answer was wrong...pleasee tell me where i went wrong.

I can't tell where you went wrong because you didn't show your work. Show your work and I'll find th error.

((2.34x10^-59)/ (2.80x10^-6)^2 (3/5)^6)^1/16= 3.99

To find the concentration of Ca2+ in the solution, we need to use the solubility product expression and apply stoichiometry.

First, let's write the solubility product expression for hydroxyapatite:

Ksp = [Ca2+]^10 [PO4^3-]^6 [OH^-]^2

Since the concentration of [OH^-] has been fixed at 2.80×10^-6 M in the question, we can substitute this value into the expression:

Ksp = [Ca2+]^10 [PO4^3-]^6 [2.80×10^-6]^2

Next, we need to consider the stoichiometry of the dissociation reaction:

Ca10(PO4)6(OH)2(s) → 10Ca2+(aq) + 6PO4^3-(aq) + 2OH-(aq)

From the reaction, we can see that for every 1 mol of Ca10(PO4)6(OH)2 that dissolves, it forms 10 mol of Ca2+. Therefore, the concentration of [Ca2+] in the solution will be 10 times higher than the concentration of [OH^-].

Now, let's rewrite the solubility product expression with the concentration of [Ca2+]:

Ksp = (10[Ca2+])^10 [PO4^3-]^6 [2.80×10^-6]^2

Now, we can solve for [Ca2+]. Rearranging the equation:

[Ca2+]^10 = Ksp / [(10[OH^-])^2 [PO4^3-]^6]

Taking the 10th root of both sides:

[Ca2+] = (Ksp / [(10[OH^-])^2 [PO4^3-]^6])^(1/10)

Substitute the given values:

[Ca2+] = (2.34×10^-59) / [(10(2.80×10^-6))^2 (PO4^3-)^6]^(1/10)

Since the concentration of [PO4^3-] is not given, we cannot solve the problem without that information. Please check if you missed any given information or let me know if there was any other relevant data provided.