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P. 189
3.3: THE SOLUBILITY PRODUCT KSP
P. 189
3.3: THE SOLUBILITY PRODUCT KSP
We do NOT
include
solids in
Keq.
Keq = ??
P. 189
3.3: THE SOLUBILITY PRODUCT KSP
3.3: THE SOLUBILITY PRODUCT KSP
P. 189
SUMMARY
CaCl2(s)  Ca2+(aq) + 2 Cl-(aq)
Ksp = [Products]
[Reactants]
Ksp =
[Ca2+(aq)][Cl-(aq)]
[CaCl2(s)]
2
SrCO3(s) ↔ Sr2+(aq) + CO32-(aq)
Mg(OH)2(s) ↔ Mg2+(aq) + 2 OH-(aq)
Ca3(PO4)2(s) ↔ 3 Ca2+(aq) + 2 PO43-(aq)
Ksp (solubility product constant) is a number representing the
concentration of species……solubility is specific and has units!
1
1
1
Ksp = 7.056 x 10-5
~ 7.1 x10-5
4.4 g/L
n = mass
Molar Mass
n = 4.4 g
278.3 g/mol
n = 0.015810 mol
Ksp = 1.6384 x 10-5
~ 1.6 x10-5
Pg 192: Practice Problem 3.3.1
#’s
1, 2, 3
P. 193
CALCULATING SOLUBILITY FROM KSP
Because Ksp uses multiplication, quite often unknown numbers (x) are
multiplied together resulting in x2, x3, or x4.
Opposite of x2 to solve these?.........2√, 3√, or 4√
X
? x 10-6 mol/L
C = 2.3
Ksp = [Fe2+][OH-]2
4.9 x 10-17 = [X][2X]2
3√ 4.9 x 10-17 =3√ 4X3
÷ 4 # = 4X ÷ 4
C=?
X
C=?
2X
X = 2.3 x 10-6 mol/L
X
? x 10-3 mol/L
C = 7.3
C=?
X
C=?
X
Ksp = [Ag+][BrO3-]
5.3 x 10-5 = [X][X]
X = 7.3 x 10-3 mol/L
√ 5.3 x 10-5 = √ X2
C = n/V
n = (C)(V)
n = (7.3 x 10-3mol/L)(0.275 L)
n=#
n = m/M
m = (n)(M)
m = (# mol)(235.8 g/mol)
m = 0.47 g
Pg 195: Practice Problem 3.3.2
#’s
1, 2, 3
P. 197
Pg 197 - 199
#’s
1(a,c,e), 2, 4, 5, 6, 10