Unit 3 - Solubility
Practice Test # 2
1.
Consider the following experiment:
1.0 mL 0.20 M Ag+
1.0 mL 020 M Sr2+
an unknown solution →
an unknown solution →
+
+
precipitate
no precipitate
The unknown solution could contain
A
B
2.
C
D
CuS
B
AgBr
C
CaCO3
D
CaSO4
A saturated solution of NaCl contains 36.5 g of solute in 0.100 L of solution. The solubility of
the compound is
A
B
0.062 M
1.60 M
C
D
4.
Calculate the [Li+] in 200.0 mL of 1.5 M Li2SO4.
A
0.30 M
5.
The Ksp expression for a saturated solution of Mg(OH)2 is
6.
0.20 M PO430.20 M SO42-
A compound has a solubility of 7.1 x 10-5 M at 25 oC. The compound is
A
3.
0.20 M OH0.20 M NO3-
B
0.60 M
C
3.65 M
6.24 M
1.5 M
A
Ksp = [Mg2+][OH-]2
[Mg(OH)2]
C
Ksp = [Mg2+][OH-]
B
Ksp = [Mg2+][OH-]2
D
Ksp = [Mg2+][2OH-]2
D
3.0 M
Consider the following saturated solution solutions
CuSO4
BaSO4
CaSO4
The order of cation concentration, from highest to lowest, is
A
B
C
D
[Ba2+]
[Ca2+]
[Cu2+]
[Cu2+]
>
>
>
>
[Ca2+]
[Cu2+]
[Ca2+]
[Ba2+]
>
>
>
>
[Cu2+]
[Ba2+]
[Ba2+]
[Ca2+]
1
7.
When 1.0 x 10-3 moles of CuCl2(s) are added to 1.0 L of 1.0 x 10-3 M IO3-, the
A
B
C
D
8.
The solubility of CdS = 2.8 x 10-14. The value of the Ksp is
A
B
9.
Trial Ksp > Ksp and a precipitate forms
Trial Ksp < Ksp and a precipitate forms
Trial Ksp > Ksp and no precipitate forms
Trial Ksp < Ksp and no precipitate forms
7.8 x 10-28
2.8 x 10-14
C
D
5.6 x 10-14
1.7 x 10-7
The ion concentrations in 0.25 M Al2(SO4)3 are
A
B
C
D
[Al3+]
[SO42-]
0.25 M
0.50 M
0.75 M
0.10 M
0.25 M
0.75 M
0.50 M
0.15 M
10.
Which of the following will not produce a precipitate when equal volumes of 0.20 M solutions
are combined?
A
KOH and CaCl2
C
Sr(OH)2 and (NH4)2S
B
Zn(NO3)2 and K3PO4
D
Na2SO4 and Pb(NO3)2
11.
Consider the following equilibrium: Mg(OH)2(s) ⇄ Mg2+(aq) + 2OH-(aq)
A compound that can be added to cause a shift to the right is
A
NaOH
12.
If the trial ion product for AgBrO3 is calculated to be 1.0 x 10-7, then
A
B
C
D
B
HCl
C
Sr(OH)2
D
a precipitate forms because the trial ion product > Ksp
a precipitate forms because the trial ion product < Ksp
no a precipitate forms because the trial ion product > Ksp
no a precipitate forms because the trial ion product < Ksp
13.
Which of the following will dissolve in water to produce a molecular solution?
A
CaCl2
14.
In a solubility equilibrium, the
A
B
C
D
Mg(OH)2
B
NaOH
C
CH3OH
D
Sr(OH)2
rate of dissolving equals the rate of crystallization
neither dissolving or crystallization occurs
concentration of solute and solvent are equal
mass of dissolved solute is greater than the mass of the solution
2
15.
The maximum [SO42-] that can exist in 1.0 x 10-3 M Ca(NO3)2 without a precipitate forming is
A
B
16.
7.1 x 10-5 M
1.0 x 10-3 M
C
D
8.4 x 10-3 M
7.1 x 10-2 M
When equal volumes of 0.20 M CuSO4(aq) and 020 M Li2S(aq) are combined, the complete ionic
equation is
A
Cu2+(aq) +
S2-(aq)
→
CuS(s)
B
CuSO4(aq)
+
Li2S(aq) →
CuS(s)
+
Li2SO4(s)
C
Cu2+(aq) + SO42-(aq) + 2Li+(aq) + S2-(aq)
→ Li2SO4(aq)
+
CuS(s)
D
Cu2+(aq) + SO42-(aq) + 2Li(aq) + S2-(aq) → CuS(s) + 2Li+(aq) + SO42-(aq)
17.
Consider the solubility equilibrium: CaCO3(aq) ⇄ Ca2+(aq) + CO32-(aq)
An additional piece of solid CaCO3 is added to the equilibrium above. The rate of dissolving and the
rate of crystallization have
A
B
C
D
Rate of Dissolving
Rate of crystallization
increases
increases
not changed
not changed
increases
not changed
increased
not changed
18.
At 25 oC, which of the following compounds would dissolve to form a saturated solution with
the greatest [Pb2+]?
A
19.
PbI2
B
PbCl2
C
PbBr2
D
Pb(IO3)2
Consider the following anions:
I 10.0 mL of 0.20 M Cl-
II 10.0 mL of 0.20 M OH-
III 10.0 mL of 0.20 M SO32-
When 10.0 mL of 0.20 M Pb(NO3)2 are added to each of the above, precipitates form in
A
B
20.
C
D
II and III only
I, II, and III
Which of the following units could be used to describe solubility?
A
21.
I and II only
I and III only
g/s
B
g/L
C
M/L
D
mol/s
The solubility of SnS is 3.2 x 10-3 M. The value of the Ksp is
A
B
1.0 x 10-5
3.2 x 10-3
C
D
6.4 x 10-3
5.7 x 10-2
3
22.
Silver chloride, AgCl, would be least soluble in
A
B
1.0 M HCl
1.0 M NaNO3
C
D
23.
The solubility of SrF2 is
A
4.3 x 10-9
24.
The Ksp expression for a saturated solution of Ag2CO3 is
A
B
B
6.6 x 10-5
C
Ksp = [Ag2+][CO32-]
Ksp = [Ag+]2[CO32-]
1.0 M ZnCl2
1.0 M AgNO3
1.0 x 10-3
C
D
D
1.6 x 10-3
Ksp = [2Ag+][CO32-]
Ksp = [2Ag+]2[CO32-]
25.
How many moles of solute are dissolved in 200.0 mL of a saturated solution of FeS?
A
1.2 x 10-19
26.
A solution contains both Ag+ and Mg2+ ions. During selective precipitation, these ions are
removed one at a time by adding
A
B
27.
I- followed by OHOH- followed by S2-
1.5 x 10-10
C
D
D
7.7 x 10-10
SO42- followed by ClNO3- followed by PO43-
the concentration of solute in a saturated solution
the moles of solute dissolved in a given amount of solution
the maximum mass of solute that can dissolve in a given amount of solution
the minimum amount of solute required to produce one litre of saturated solution
[Al3+]
[SO42-]
0.25 M
0.50 M
0.75 M
0.10 M
0.25 M
0.75 M
0.50 M
0.15 M
Which of the following will not produce a precipitate when equal volumes of 0.20 M solutions
are combined?
A
B
30.
C
The ion concentrations in 0.25 M Al2(SO4)3 are
A
B
C
D
29.
6.0 x 10-19
Which of the following does not define solubility?
A
B
C
D
28.
B
KOH and SrCl2
Zn(OH)2 and K3PO4
C
D
Zn(OH)2 and (NH4)2S
Na2SO4 and Pb(NO3)2
What is observed when H2SO4 is added to a saturated solution of CaSO4?
A
B
CaSO4(s) dissolves
the [Ca2+] increases
C
D
bubbles of H2 are given off
additional CaSO4 precipitates
4
31. The solubility of CdS is 2.8 x 10-14 M. The value of the Ksp is
A
B
32.
7.8 x 10-28
2.8 x 10-14
C
D
5.6 x 10-14
1.7 x 10-7
Consider the following solutions: 0.10 M Cl- 0.10 M Br- 0.10 M IO3-
0.10 M BrO3-
Equal moles of AgNO3 are added to each solution. It is observed that a precipitate forms in all
but one solution. Which solution does not form a precipitate?
A
B
33.
ClBr-
C
D
IO3BrO3-
Consider the following equilibrium: 2O3(g) ⇄ 3O2(g) Keq = 65
Initially, 0.10 mole O3 and 0.10 mole of O2 are placed in a 1.0 L container. Which of the
following describes the changes in concentrations as the reaction proceeds to equilibrium?
A
B
C
D
35.
[O3]
[O2]
decreases
decreases
increases
increases
decreases
increases
decreases
increases
Increasing the temperature of a reaction increases the rate by
I
II
III
increasing frequency of collision
increasing the kinetic energy of collision
decreasing the potential energy of collision
A
I only
B
I and II only
C II and III only
36.
What is the Keq expression for the following equilibrium?
D
I, II, and III
Fe (s) + 4H2O(g) ⇄ Fe3O4(s) + 4H2(g)
A
1.
Keq = [H2]4
C
B
D
Keq = [H2]
[H2O]
Keq = [H2]4
[H2O]4
Keq = [Fe3O4][H2]4
[Fe]3[H2O]4
Write the net ionic equation representing the reaction that occurs when 50.0 mL of 0.20 M
ZnSO4 and 50.0 mL 0.20 M BaS are combined.
5
2.
A 100.0 mL sample of 0.600M Ca(NO3)2 is diluted by adding 400.0 mL of water. Calculate the
concentrations of all of the ions.
3.
When 1.00 L of CaF2 was evaporated to dryness, 2.66 x 10-2 g of residue was formed. Calculate
the Ksp.
4.
A maximum of 0.60 g Pb(NO3)2 can be added to 1.5 L of NaBr(aq) without forming a
precipitate. Calculate the [NaBr].
5.
Consider the following solutions at 25 oC
Saturated AgCl(aq)
Saturated Ag2CO3(aq)
Using calculations, identify the solution with the greater [Ag+].
6
ANSWERS to the Practice Test #2
1. Consider the following experiment:
1.0 mL 0.20 M Ag+
+
an unknown solution →
precipitate
1.0 mL 020 M Sr2+
+
an unknown solution →
no precipitate
The unknown solution could contain
A
B
C
D
0.20 M OH- low with Ag+ and high with Sr2+
0.20 M NO30.20 M PO430.20 M SO42-
2. A compound has a solubility of 7.1 x 10-5 M at 25 oC. The compound is
A
B
C
D
CuS
AgBr
CaCO3
CaSO4
square the solubility
3. A saturated solution of NaCl contains 36.5 g of solute in 0.100 L of solution. The solubility of the
compound is
A
B
C
D
0.062 M
1.60 M
3.65 M
6.24 M
4. Calculate the [Li+] in 200.0 mL of 1.5 M Li2SO4.
A
B
C
D
0.30 M
0.60 M
1.5 M
3.0 M Do not divide by L
5. The Ksp expression for a saturated solution of Mg(OH)2 is
A
Ksp = [Mg2+][OH-]2
[Mg(OH)2]
B
Ksp = [Mg2+][OH-]2
C
Ksp = [Mg2+][OH-]
D
Ksp = [Mg2+][2OH-]2
7
6. Consider the following saturated solution solutions
CuSO4
BaSO4
CaSO4
The order of cation concentration, from highest to lowest, is
A
B
C
D
[Ba2+]
[Ca2+]
[Cu2+]
[Cu2+]
>
>
>
>
[Ca2+]
[Cu2+]
[Ca2+]
[Ba2+]
>
>
>
>
[Cu2+]
[Ba2+]
[Ba2+] largest to smallest Ksp
[Ca2+]
7. When 1.0 x 10-3 moles of CuCl2(s) are added to 1.0 L of 1.0 x 10-3 M IO3-, the
A
B
C
D
Trial Ksp > Ksp and a precipitate forms
Trial Ksp < Ksp and a precipitate forms
Trial Ksp > Ksp and no precipitate forms
Trial Ksp < Ksp and no precipitate forms
8. The solubility of CdS = 2.8 x 10-14 M. The value of the Ksp is
A
B
C
D
7.8
2.8
5.6
1.7
x
x
x
x
10-28
10-14
10-14
10-7
Square the solubility
9. The ion concentrations in 0.25 M Al2(SO4)3 are
A
B
C
D
[Al3+]
[SO42-]
0.25 M
0.50 M
0.75 M
0.10 M
0.25 M
0.75 M
0.50 M
0.15 M
10. Which of the following will not produce a precipitate when equal volumes of 0.20 M solutions are
combined?
A
B
C
D
KOH and CaCl2
Zn(NO3)2 and K3PO4
Sr(OH)2 and (NH4)2S
Na2SO4 and Pb(NO3)2
Both have high solubility
11. Consider the following equilibrium: Mg(OH)2(s) ⇄ Mg2+(aq) + 2OH-(aq)
A compound that can be added to cause a shift to the right is
A
B
NaOH
HCl Acids react with OH8
C
D
Sr(OH)2
Mg(OH)2
12. If the trial ion product for AgBrO3 is calculated to be 1.0 x 10-7, then
A
B
C
D
a precipitate forms because the trial ion product > Ksp
a precipitate forms because the trial ion product < Ksp
no a precipitate forms because the trial ion product > Ksp
no a precipitate forms because the trial ion product < Ksp
13.Which of the following will dissolve in water to produce a molecular solution?
A
B
C
D
CaCl2
NaOH
CH3OH
Sr(OH)2
One of these things is not kike the other
14. In a solubility equilibrium, the
A
B
C
D
rate of dissolving equals the rate of crystallization
neither dissolving or crystallization occurs
concentration of solute and solvent are equal
mass of dissolved solute is greater than the mass of the solution
15. The maximum [SO42-] that can exist in 1.0 x 10-3 M Ca(NO3)2 without a precipitate forming is
A
B
C
D
7.1
1.0
8.4
7.1
x 10-5 M
x 10-3 M
x 10-3 M
x 10-2 M
16. When equal volumes of 0.20 M CuSO4(aq) and 020 M Li2S(aq) are combined, the complete ionic
equation is
A
Cu2+(aq) +
S2-(aq)
→
CuS(s)
B
CuSO4(aq)
+
Li2S(aq) →
CuS(s)
+
Li2SO4(s)
2+
2+
2C
Cu (aq) + SO4 (aq) + 2Li (aq) + S (aq)
→ Li2SO4(aq)
+
CuS(s)
D
Cu2+(aq)
+ SO42-(aq) + 2Li(aq) + S2-(aq) → CuS(s) + 2Li+(aq) + SO42-(aq)
17. Consider the solubility equilibrium:
CaCO3(aq) ⇄ Ca2+(aq) + CO32-(aq)
An additional piece of solid CaCO3 is added to the equilibrium above. The rate of dissolving and the
rate of crystallization have
A
B
C
D
Rate of Dissolving
Rate of crystallization
increases
increases
not changed
not changed
increases
not changed
increased
not changed
9
18. At 25 oC, which of the following compounds would dissolve to form a saturated solution with the
greatest [Pb2+]?
A
B
C
D
PbI2
PbCl2
PbBr2
Pb(IO3)2
largest Ksp
19. Consider the following anions:
I
II
III
10.0 mL of 0.20 M Cl10.0 mL of 0.20 M OH10.0 mL of 0.20 M SO32-
When 10.0 mL of 0.20 M Pb(NO3)2 are added to each of the above, precipitates form in
A
B
C
D
I and II only
I and III only
II and III only
I, II, and III
20. Which of the following units could be used to describe solubility?
A
B
C
D
g/s
g/L
M/L
mol/s
21. The solubility of SnS is 3.2 x 10-3 M. The value of the Ksp is
A
B
C
D
1.0
3.2
6.4
5.7
x
x
x
x
10-5
10-3
10-3
10-2
square the solubility
22. Silver chloride, AgCl, would be least soluble in
A
B
C
D
1.0 M HCl
1.0 M NaNO3
1.0 M ZnCl2
1.0 M AgNO3
23. The solubility of SrF2 is
A
B
4.3 x 10-9
6.6 x 10-5
10
C
D
1.0 x 10-3
1.6 x 10-3
square-root the Ksp
24. The Ksp expression for a saturated solution of AgCO3 is
A
B
C
D
Ksp
Ksp
Ksp
Ksp
=
=
=
=
[Ag2+][CO32-]
[Ag+]2[CO32-]
[2Ag+][CO32-]
[2Ag+]2[CO32-]
25. How many moles of solute are dissolved in 200.0 mL of a saturated solution of FeS?
A
B
C
D
1.2
6.0
1.5
7.7
x
x
x
x
10-19
10-19
10-10
10-10
26. A solution contains both Ag+ and Mg2+ ions. During selective precipitation, these ions are removed
one at a time by adding
A
B
C
D
I- followed by OHOH- followed by S2SO42- followed by ClNO3- followed by PO43-
27. Which of the following does not define solubility?
A
B
C
D
the concentration of solute in a saturated solution
the moles of solute dissolved in a given amount of solution
the maximum mass of solute that can dissolve in a given amount of solution
the minimum amount of solute required to produce one litre of saturated solution
28. The ion concentrations in 0.25 M Al2(SO4)3 are
A
B
C
D
[Al3+]
[SO42-]
0.25 M
0.50 M
0.75 M
0.10 M
0.25 M
0.75 M
0.50 M
0.15 M
29. Which of the following will not produce a precipitate when equal volumes of 0.20 M solutions are
combined?
A
B
C
KOH and SrCl2
Zn(OH)2 and K3PO4
Zn(OH)2 and (NH4)2S
11
D
Na2SO4 and Pb(NO3)2
30. What is observed when H2SO4 is added to a saturated solution of CaSO4?
A
CaSO4(s) dissolves
B
the [Ca2+] increases
C
bubbles of H2 are given off
D
additional CaSO4 precipitates
31. The solubility of CdS is 2.8 x 10-14 M. The value of the Ksp is
A
B
C
D
7.8
2.8
5.6
1.7
x
x
x
x
10-28
10-14
10-14
10-7
32. Consider the following solutions: 0.10 M Cl-
0.10 M Br-
0.10 M IO3-
0.10 M BrO3-
Equal moles of AgNO3 are added to each solution. It is observed that a precipitate forms in all but one
solution. Which solution does not form a precipitate?
A
B
C
D
ClBrIO3BrO3- highest Ksp
33. Consider the following equilibrium: 2O3(g) ⇄ 3O2(g) Keq = 65
Initially, 0.10 mole O3 and 0.10 mole of O2 are placed in a 1.0 L container. Which of the following
describes the changes in concentrations as the reaction proceeds to equilibrium?
A
B
C
D
[O3]
[O2]
decreases
decreases
increases
increases
decreases
increases
decreases
increases
34.Consider the following potential energy diagram for the reversible reaction.
PE
(KJ)
140
130
110
Progress of the reaction
12
A
B
C
D
Activation Energy (kJ)
ΔH (kJ)
10
10
30
20
-20
-30
+10
+30
35. Increasing the temperature of a reaction increases the rate by
I
II
III
increasing frequency of collision
increasing the kinetic energy of collision
decreasing the potential energy of collision
A
B
C
D
I only
I and II only
II and III only
I, II, and III
36. What is the Keq expression for the following equilibrium?
Fe (s) + 4H2O(g) ⇄ Fe3O4(s) + 4H2(g)
A
Keq = [H2]4
B
Keq = [H2]
[H2O]
C
Keq = [H2]4
[H2O]4
D
Keq = [Fe3O4][H2]4
[Fe]3[H2O]4
13
Subjective
1. Write the net ionic equation representing the reaction that occurs when 50.0 mL of 0.20 M ZnSO4
and 50.0 mL 0.20 M BaS are combined.
ZnSO4(aq) + BaS(aq) → BaSO4(s) + ZnS(s)
Zn2+ + SO42- + Ba2+ + S2- → BaSO4(s) +
Zn2+ + SO42- + Ba2+ + S2- → BaSO4(s) +
ZnS(s)
ZnS(s)
2. A 100.0 mL sample of 0.600M Ca(NO3)2 is diluted by adding 400.0 mL of water. Calculate the
concentrations of all of the ions.
Ca(NO3)2
(100) 0.600 M
(500)
⇄
Ca2+
+
0.120 M
2NO3-
0.240 M
14
3. When 1.00 L of CaF2 was evaporated to dryness, 2.66 x 10-2 g of residue was formed. Calculate the
Ksp.
Molarity =
2.66 x 10-2 g x 1 mole
78.1 g
1.00 L
⇄
CaF2
3.406 x 10-4 M
Ksp
= 3.406 x 10-4 M
Ca2+
+
3.406 x 10-4 M
2F6.812 x 10-4 M
= (3.406 x 10-4 )(6.812 x 10-4) 2
= 1.58 x 10-10
4. A maximum of 0.60 g Pb(NO3)2 can be added to 1.5 L of NaBr(aq) without forming a precipitate.
Calculate the [NaBr].
Molarity =
0.60 g x 1 mole
331.2 g
1.5 L
= 0.001208 M
15
⇄
PbBr2
Pb2+
2Br-
+
[Br-]
0.001208 M
Ksp = [Pb2+][Br-]2
6.6 x 10-6 = [0.001208][Br-]2
[Br-] = 7.4 x 10-2 M
5. Consider the following solutions at 25 oC
saturated AgCl(aq)
saturated Ag2CO3(aq)
Using calculations, identify the solution with the greater [Ag+].
AgCl(s) ⇄
Ag+ +
Cl-
Ag2CO3(s)
x
x
x
x
Ksp
=
x2
1.8 x 10-10 = x2
x
=
1.3 x 10-5 M
[Ag+] = 1.3 x 10-5 M
⇄
2Ag+ +
CO32-
2x
x
Ksp = 4x3
8.5 x 10-12 = 4x3
x
=
1.286 x 10-4 M
[Ag+] = 2x = 2.6 x 10-4 M
Greater
16