The solubility product for calcium phosphate is 2.0x10^-29. A. Calculate the mol
ID: 825586 • Letter: T
Question
The solubility product for calcium phosphate is 2.0x10^-29.
A. Calculate the molar solubility of calcium phosphate, and the concentrations of
the calcium and phosphate ions at equilibrium.
B. Using Excel, create a spreadsheet that calculates the calcium and phosphate ion
concentrations at equilibrium following the addition of 1.0x10^-8
M to
1.0x10^-7
M calcium chloride, in increments of 1.0x10^-9
M. From this data, plot
the concentration of the phosphate ion versus the concentration of the calcium
ion at equilibrium. (You may want to multiply the concentrations by some
constant value to make it easier to read the axes labels.) Print out and turn in
your plot with sample calculations (handwritten) of the calcium and phosphate
ion concentrations calculated for any three points between 1.0x10^-8
M to
1.0x10^-7
M calcium chloride. (Make sure you plot adheres to the required
standards on page 33 of the lab manual.)
Explanation / Answer
Ca3(PO4)2 ---------------------------------------> 3 Ca 2+ + 2 PO4 3-
x 3x 2x
so solubility product = [Ca2+]^3 [PO43-]^2
molar solubility = 2*10^-29 M
(3x)^3 *(2x)^2 = 2*10^-29
so 108 x^5 = 2*10^-29
so x^5 = 0.1851 * 10^-30
so x= 0.713* 10^-6
so [Ca2+] = 3x = 2.14 *10^-6 M
[PO4 3-] = 2x = 1.426*10^-6M