Practice Questions for Exam 3
CH 1020 Spring 2017
1. Which of the following can be considered a
Brønsted-Lowry base?
5. What is the pH of a solution for which
[Ba(OH)2] = 0.015 M?
6. The figure below shows three acids HX, HY and
HZ, (water molecules are omitted for clarity).
Which acid has the largest pKa?
I
A.
B.
C.
D.
E.
II
III
I only
II only
III only
I and II
II and III
2. Upon losing a proton, a Brønsted acid becomes…
A.
B.
C.
D.
E.
highly reactive
its conjugate base
its conjugate acid
a hydronium ion
a hydroxide ion
3. Consider 0.10 M solutions of the following: HNO2,
NaOH, NH3 and HI. One of the solutions was
found to have a pH of 11.12 and another solution, a
pH of 1.67. What are the identities of the two
solutions?
A. The solution with pH = 11.12 is NaOH and the
solution with pH = 1.67 is HI.
B. The solution with pH = 11.12 is NaOH and the
solution with pH = 1.67 is HNO2.
C. The solution with pH = 11.12 is HI and the
solution with pH = 1.67 is NaOH.
D. The solution with pH = 11.12 is NH3 and the
solution with pH = 1.67 is HI.
E. The solution with pH = 11.12 is NH3 and the
solution with pH = 1.67 is HNO2.
4. The ionization constant, Kw, of water at 60 oC is
1.00  1013. What is the pH of pure water at this
temperature?
A.
B.
C.
D.
HX
HY
HZ
it depends on the amount of acid present.
7. In this reaction the equilibrium favors reactants
(lies to the left as written). Which species is the
strongest base?
H
H
N
H
+
O
H
H
H
N
H
+
H
O
H
H
A. NH3
B. H2O
C. NH4+
D. OH–
8. Calculate the hydroxide ion concentration for an
aqueous solution that has a pH of 3.45.
9. Which of the following solutions will have the
lowest pH?
A.
B.
C.
D.
E.
0.10 M HCN (Ka = 6.2  1010)
0.10 M HIO3 (Ka = 1.6  101)
0.10 M HF (Ka = 6.8  104)
0.10 M CH3COOH (Ka = 1.8  105)
0.10 M HNO2 (Ka = 7.1  104)
CH 1020 Spring 2017 Practice Questions for Exam 3
10. Which of the acids in question 9 has the strongest
conjugate base?
A. HCN
B. HIO3
C. HF
D. CH3COOH
E. HNO2
Page 2 of 7
17. In an aqueous solution which is 0.1 M sodium
acetate, CH3CO2Na, the concentration of
hydronium ions [H3O+] is….
A.
B.
C.
D.
11. A 0.10 M aqueous solution of an acid has a pH of
5.44. What is the value of Ka for this acid?
12. What is the pH of a solution that contains 0.033 M
boric acid, H3BO3? The Ka for boric acid is
5.4  1010.
13. What is the pH of a 0.050 M solution of
chloroacetic acid? For chloroacetic acid,
Ka = 1.4  103.
14. What is the percent dissociation of a weak acid if
its initial concentration is 1.5 M and its
Ka = 4.5  104?
15. Consider a generic polyprotic acid H2YO3. What
is an appropriate combination of acid dissociation
constants for this acid?
Ka1
Ka2
A. 2.1  104
8.9  105
B. 3.2  106
2.2  1010
C. 4.5  1010
6.7  106
D. 5.3  105
1.8  104
16. An aqueous solution of which of the following
salts will give the most basic solution?
A. NaOCl
B. NaCl
C. NaClO2
D. NaClO3
less than the [H3O+] in 0.1 M acetic acid.
equal to the [H3O+] in 0.1 M acetic acid.
greater than the [H3O+] in 0.1 M acetic acid.
impossible to compare with the [H3O+] in
0.1 M acetic acid.
18. Classify each of the following salt solutions as
neutral, basic or acid.
A. Na2CO3
B. NH4Cl
C. CaBr2
D. KNO2
19. What is the pH of a solution prepared by mixing
40.0 mL of a 0.15 M solution of HF with 50.0 mL
of a 0.20 M solution of NaF? (The Ka of HF is
3.5  104.)
20. Blood is buffered by the carbonic acid/bicarbonate
buffer system (H2CO3/HCO3–). If the pH of the
blood starts to rise (for example if your kidneys
fail to metabolize urea properly) which component
of the buffer system will react to maintain the
correct pH?
A. H2O
B. CO32
C. HCO3
D. H2CO3
21. You have the following bases and want to prepare
a buffer solution with pH = 8.90. Which one do
you choose?
A.
B.
C.
D.
E.
cinnoline
pyridine
ketamine
codeine
dibutylamine
Kb = 2.3  1012
Kb = 1.7  109
Kb = 3.0  107
Kb = 1.6  106
Kb = 1.8  103
22. Given 100.0 mL of a buffer that is 0.50 M in HOCl
and 0.40 M in NaOCl, what is the pH after
10.0 mL of 1.0 M NaOH has been added? (Ka for
HOCl = 3.5  108).
CH 1020 Spring 2017 Practice Questions for Exam 3
23. What is the [H3O+] concentration of a solution
formed by mixing 50.0 mL of 0.20 M HCl and
50.0 mL of 0.10 M NaOH?
Page 3 of 7
27. How many electrons are transferred in the
balanced redox reaction for the electrochemical
cell summarized below?
Al(s) | Al3+(aq) || Cd2+(aq) | Cd(s)
24. Shown below is a titration curve for ascorbic acid
(Vitamin C).
28. What is E° for the galvanic cell represented in
question 26?
29. Three metals, A, B, and C, are immersed in
solutions with their respective cations and then
tested in a galvanic cell with the following results:
A and B: A is the cathode
B and C: C is the cathode
A and C: A is the anode
Ascorbic acid is a ….
A.
B.
C.
D.
What is the order of reduction potentials of the
cations, from highest to lowest?
strong acid
strong base
weak acid
weak base
25. Based on the above titration curve, what is the
approximate pKa for ascorbic acid?
A. 2.80
B. 6.00
C. 10.60
D. 4.10
E. 8.70
26. A 1.0 g sample of an unknown substance was
titrated with a 0.1 M HCl solution (Figure 1).
Another 1.0 g sample of it was titrated with a 0.1
M NaOH solution (Figure 2). Given the following
possibilities, what is the sample?
Figure 1
highest E°reduction  lowest
A. A > B > C
B. C > B > A
C. C > A > B
D. B > A > C
E. A > C > B
F. B > C > A
30. Based on the cell information below, determine the
standard reduction potential for the following
reaction.
Mn2+(aq) + 2e  Mn(s)
Mn(s) | Mn2+ (1 M) ‖ 2H+ (1 M) | H2 (1 atm) | Pt(s)
Ecell = +1.18 V
Figure 2
31. Copper will spontaneously reduce which of the
following?
A.
B.
C.
D.
E.
Na2CO3
NaHCO3
H2CO3
KOH
HNO2
A.
B.
C.
D.
E.
Fe2+ and Ag+
Fe2+
Ag+
Al3+
Fe2+ and Al3+
CH 1020 Spring 2017 Practice Questions for Exam 3
32. For the galvanic cell pictured below, which
statement is true?
Page 4 of 7
35. Which of the following is true for the cell
represented here?
Zn(s) | Zn2+(aq) || Sn2+(aq) | Sn(s)
A. The electrons flow from the zinc electrode to
the tin electrode.
B. The electrons flow from the tin electrode to the
zinc electrode.
C. The tin electrode is oxidized.
D. The zinc electrode is reduced.
36. What is ΔG for the reaction below?
2 AlI3(aq)  2 Al(s) + 3I2(s)
A. Potassium ions from the salt bridge flow
toward the Fe electrode as the electrode is
oxidized.
B. Potassium ions from the salt bridge flow
toward the half-cell where Fe3+ is reduced.
C. Potassium ions from the salt bridge flow
toward the Cr electrode as the electrode is
oxidized.
D. Potassium ions from the salt bridge flow
toward the half-cell where Cr3+ is reduced.
37. What is E°cell for the following net ionic reaction if
its equilibrium constant is 72?
Ru2+(aq) + Tc(s)  Ru(s) + Tc2+(aq)
38. Consider the following electrochemical cell.
Cu(s) | Cu2+(aq) || Fe3+(aq), Fe2+(aq) | Pt(s)
Which action will make Ecell more positive?
332 What is E° for the galvanic cell depicted
question 31?
34. Which of the following statements is true for the
galvanic cell depicted below?
A.
B.
C.
D.
E.
F.
Increasing [Fe3+]
Increasing [Cu2+]
Increasing [Fe2+]
Increasing the mass of Cu(s).
Both A and D.
Both B and C.
39. What is the potential at 25.0 °C of the cell
represented below?
Zn(s) | Zn2+ (aq, 0.010 M) || Ag+ (aq, 0.20 M) | Ag(s)
40. Consider the following reaction at 25 C.
Cu2+(aq) + Fe(s)  Cu(s) + Fe2+(aq)
A. The mass of the Sn electrode decreases during
the reaction.
B. Sn is the cathode.
C. The concentration of Cu2+ increases as the
reaction proceeds.
D. Cu2+ is the anode.
What is [Fe2+] if [Cu2+] = 0.040 M and
Ecell = 0.76 V?
CH 1020 Spring 2017 Practice Questions for Exam 3
41. For an electrolytic cell, which is the correct
combination?
A.
B.
C.
D.
E°
+
+


G°

+

+
42. Identify the family for each of the following.
A.
B.
C.
D.
E.
CH3CH2OCH3
CH3CH2CH2OH
CH3CHCH2
CH3CH2COOH
CH3CH2NH2
43. To which family does the following belong?
Page 5 of 7
46. Which of the following names is correct?
A.
B.
C.
D.
E.
47. Arrange the following by increasing vapor
pressure?
I.
II.
III.
IV.
V.
alkene
aromatic
alkyne
alcohol
alkane
HOCH2CH2CH2OH
CH3(CH2)5CH3
CH3CH2CH2CH2OH
CH3OCH2CH2CH3
CH3CH2CH2CH2NH2
48. Arrange the following by increasing boiling point.
I.
II.
III.
IV.
V.
A.
B.
C.
D.
E.
1,2-dimethylhexane
2-ethyl-3-methyl-2-butanol
4-methyl-3-pentene
3-ethyl-2-methylhexane
4-ethyl-2-methylpentane
CH3CH2CH2NH2
CH3CH2OCH3
CH2CH=CHCH3
CH3CH2CH2CH3
CH3CH2CH2OH
49. Arrange the following organic compounds by
increasing solubility in water.
I.
II.
III.
IV.
CH3CH2OCH2CH3
CH3CH2CH2CH2CH3
CH3CH2CH2CH2OH
CH3CH2CO2H
44. Provide the chemical formula for the following.
50. In which of the following is hydrogen bonding
likely to be the most significant component of the
total intermolecular forces?
45. Name the following.
A.
B.
C.
D.
E.
CH4
C5H11OH
C6H13NH2
CH3OH
CO2
CH 1020 Spring 2017 Practice Questions for Exam 3
51. Which of the following are structural
(constitutional) isomers?
CH3 CH CH CH3
A.
H2C
CH2
H2C
CH2
CH2
Structure II
Structure I
CH3 CH CH CH3
CH3 CH CH2 CH2 CH3
CH3
Structure IV
Structure III
Structures II and IV
Structures I and III
Structures I, II, III and IV
Structures I and IV
Structures II and IV
52. Which of the following compounds exhibits
cis/trans isomerism?
A. CHCl=CHCH3
B. CHCl=CH2
B.
CH3
CH3
A.
B.
C.
D.
E.
53. Which one of the following is NOT a structural
isomer of octane?
CH2
CH3 CH3
Page 6 of 7
C.
D.
E.
C. CCl2=CH2
D. CH2=CHCH3
54. Name the five compounds in the above question.
USEFUL INFORMATION
pH = pKa + log
[base]
[acid]
Ka · Kb = Kw = 1.00 x 1014 at 25 °C
Go = nFE
E = E 
E =
RT
ln Q
nF
RT
ln K
nF
1 V = 1 J/C
At 298 K:
E = E 
At 298 K:
E =
0.0257
ln Q
n
0.0257
ln K
n
1 F = 96,500 C/mol e
E = E 
E =
Reduction Half Reaction
Ag+(aq) + e→ Ag(s)
I2(s) + 2e
-
Eo
0.80 V
→
Fe2+(aq)
0.77 V

2I(aq)
0.54 V

Cu(s)
0.52 V
-
→
Cu(s)
0.34 V
2H (aq) + 2eFe3+(aq) + 3e-

H2(g)
0.00
+
Cu (aq) + e
-
2+
Cu (aq) + 2e
+

Fe(s)
0.04 V
2+
-

Sn(s)
0.14 V
2+
-

Cd(s)
0.40 V
2+
-
Fe (aq) + 2e
Cr3+(aq) + 3e-
→
Fe(s)
0.45 V

Cr(s)
0.74 V
Zn (aq) + 2eAl3+(aq) + 3e-

Zn(s)
0.76 V
→
Al(s)
1.66 V
Sn (aq) + 2e
Cd (aq) + 2e
2+
0.0591
log K
n
R = 8.314 J/K·mol = 0.08206 L·atm/ K·mol
Table 1. Standard Reduction Potentials at 25 C
Fe3+(aq) + e-
0.0591
log Q
n