Solubility p.1
Define solubility and list the two ways (units) for which solubility is measured
g/100g H2O
moles/L
List the 5 ions that will always be soluble (that you should memorize!)
Na+, NH4+, NO3-, C2H3O2-, K+
The value of Ksp of AgCl is 1.8 x 10-10. What are the individual molar solubilities for Ag+ and Cl-?
Ksp = [Ag+][Cl-]
1.8 x 10-10 = (x)(x)
x = 1.3 x 10-5
Write out the equation for the solubility-product expression for the dissociation of the compound Ba(OH)2.
Ksp = [Ba2+][OH-]2
The molar solubility of Barium iodate, Ba(IO3)2, at 35°C is 1.0 x 10–3 M. Calculate Ksp at this temperature.
R Ba(IO3)2 --> Ba2+ + 2IO3-
I
C -x +x +2x
E -x x 2x
x = 1.0 x 10-3
Ksp = (x)(2x)2
Ksp = (1.0 x 10-3)(2 • 1.0 x 10-3)2
Ksp = 4.0 x 10-9
The molar solubility of copper(I) chloride, CuCl is 1.1 x 10-3 at 25ºC. Calculate Ksp.
CuCl (s) --> Cu+ + Cl-
x = 1.1 x 10-3
Ksp = [Cu+][Cl-]
Ksp = (1.1 x 10-3)(1.1 x 10-3) = 1.3 x 10-6
What is the molar solubility of Er(IO3)3?
Ksp = 2.0 x 10-21
R Er(IO3)3 ---> Er3+ + 3IO3-
I
C -x +x +3x
E -x x 3x
2.0 x 10-21 = x(3x)3
Follow up problem to Solubility for 400:
What is the solubility of Er(IO3)3 in grams for 100 ml of water?
molar solubility mol/L • 691.968 g/mol = g/L • 1/10 = g/100mL
What is the molar solubility of Er(IO3)3 that is in 0.010M of KIO3?
Ksp = 2.0 x 10-21
R Er(IO3)3 ---> Er3+ + 3IO3-
I 0 0 0.010M
C -x +x +3x
E -x x 0.010 + 3x
2.0 x 10-21 = (x)(0.010 + 3x)3
Neglect x! :D
2.0 x 10-21 = 1.0 x 10-6
x = 2.0 x 10-15 M
Calculate the molar solubility of Ag2SO4 in 0.10 M AgNO3.
Ksp = 1.2 x 10-5
R Ag2SO4 --> 2Ag+ + SO42-
I 0 0.10 0
C -x +2x +x
E -x 0.10 + 2x x
Ksp = x(0.10 + 2x)2
1.2 x 10-5 = x(0.10)2
x = 0.0012