2Group Quiz: Solubility Unit Problems (Due Monday)
1. Calculate the Ksp for each of the salts whose solubility is listed below.
a) CaSO4 = =5.0 x 10-3 mol/= x^2 =2.50E-05
b) MgF2 = 2.7 x 10-3 mol/L 4x^3=
7.873E-08
c) AgC2H3O2 = 1.02 g/100 mL x^2=3.73E-3 (MM=166.9)
d) SrF2 = 12.2 mg/100 mL 4x^3= 3.66E-9 (MM 125.6)
2. Calculate
a) the solubility in moles/L of each of three salts and
b) the concentration of the cations in mg/mL in each of the saturated solutions.
i) AgCN Ksp = 2.0 x 10-12 1.414E-06 M
ii) BaSO4 Ksp = 1.5 x 10-9 3.873E-05 M
iii) FeS Ksp = 3.7 x 10-19 6.083E-10 M
iv) Mg(OH)2 Ksp = 9.0 x 10-12 1.310E-04M
v) Ag2S Ksp = 1.6 x 10-49 3.420E-17 M
vi) CaF2 Ksp = 4.9 x 10-11 2.305E-04 M
1.53E-04
5.32E-03
3,40E-8
3,20E-3
7.38E-15
9.24E-03
mg/ml
mg/ml
mg/ml
mg/ml
mg/ml
mg/ml
MM=
MM=
MM=
MM
MM=
MM=
107.9
137.3
55.8
24.3
107.9
40.1
3. Consider these slightly soluble salts:
i) PbS Ksp = 8.4 x 10-28 x=
2.898E-14
-8
ii) PbSO4 Ksp = 1.8 x 10 x=
1.342E-04
iii) Pb(IO3)2 Ksp = 2.6 x 10-13 x= 4.021E-05
M
M
M
a)Which is the most soluble? ) PbSO4 Ksp = 1.8 x 10-8
b) Calculate the solubility in moles/L for PbSO4. 1.342E-04
M
c) How many grams of PbSO4 dissolve in 1 L of solution? 1.342E-04*303.3 =4.07E02
d) How can you decrease the concentration of Pb2+(aq) in a saturated solution of
PbSO4 solution? Add SO4
e) What is the concentration in moles/L of PbS in a saturated solution of the salt?
2.898E-14
4. For each of these substances, calculate the milligrams of metallic ion that can
remain at equilibrium in a solution having a [OH-] = 1.0 x 10-4 mol/L. which would
be a pH= 10
a) Cu(OH)2 Ksp = 1.6 x 10-9 x*(10-4)^2 =Ksp
x= 1.60E-01M 10.17 g/L of Cu
b) Fe(OH)3 Ksp = 6.0 x 10-38 x*(10-4)^3 =Ksp
x=6.00E-26=M
c) Mg(OH)2 Ksp = 6.0 x 10-12 x*(10-4)^2 =Ksp
3.35E-24 g/L of Fe
x=6.00E-04M 1.46E-2 g/L of Mg