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| 1 | |
Which of the following statements is incorrect? |
| | A) | In an electrolytic cell, reduction occurs at the anode. |
| | B) | Aluminum metal would form at the cathode during the electrolysis of molten AlBr3. |
| | C) | The cathode is labeled "+" in a voltaic cell. |
| | D) | Oxidation occurs at the anode in a voltaic cell. |
| | E) | Electrons flow from the anode to the cathode in all electrochemical cells. |
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| 2 | |
Consider the following notation for an electrochemical
cell
Zn|Zn2+ (1M)||Fe2+ (1M), Fe3+ (1M)|Pt
What is the balanced equation for the cell reaction? |
| | A) | Zn(s) + 2Fe3+(aq) → 2Fe2+(aq) + Zn2+(aq) |
| | B) | Zn2+(aq) + 2Fe2+(aq) → Zn(s) + 2Fe3+(aq) |
| | C) | Zn(s) + 2Fe2+(aq) → 2Fe3+(aq) + Zn2+(aq) |
| | D) | Zn(s) + Fe3+(aq) → Fe2+(aq) + Zn2+(aq) |
| | E) | Zn(s) + Fe2+(aq) → Fe(s) + Zn2+(aq) |
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| 3 | |
A voltaic cell is constructed from the following half-cells, linked by a KCl
salt bridge:
(a) an Fe electrode in 1.0 M FeCl2 solution
(b) a Ni electrode in 1.0 M Ni(NO3)2 solution
Use the table of standard electrode potentials in your textbook to decide which one of the following statements is correct. |
| | A) | The Ni electrode is the anode. |
| | B) | Electrons flow from the iron electrode to the nickel electrode. |
| | C) | The iron electrode is positively charged. |
| | D) | The iron electrode will gain mass when current flows. |
| | E) | The salt bridge conducts electrons through solution. |
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| 4 | |
Consider the electrochemical cell:
Zn(s) | Zn2+(aq) || Br-(aq) | Br2(l) | Pt
Use data from the table of standard electrode potentials in your textbook to calculate the standard potential of this cell, E°cell. |
| | A) | 0.31 V |
| | B) | 1.83 V |
| | C) | -0.31 V |
| | D) | 1.30 V |
| | E) | none of the above |
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| 5 | |
When combined with a Cu2+/Cu electrode (E° = 0.34V), which of the following electrodes will produce the largest standard cell potential? |
| | A) | M+/M, E° = 1.00 V |
| | B) | M2+/M, E° = 0.90 V |
| | C) | X2/X-, E° = 0.95 V |
| | D) | M2+/M, E° = -0.30 V |
| | E) | M+/M, E° = -0.50 V |
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| 6 | |
Consider the following half-reactions and select the strongest oxidizing agent
present:
Sr2+(aq) + 2e- → Sr(s) E° = -2.89 V
Cr2+(aq) + 2e- → Cr(s) E° = -0.913 V
Co2+(aq) + 2e- → Co(s) E° = -0.28 V |
| | A) | Cr2+(aq) |
| | B) | Sr2+(aq) |
| | C) | Co2+(aq) |
| | D) | Sr(s) |
| | E) | Co(s) |
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| 7 | |
Given the following standard reduction potentials in acid
solution:
Al3+(aq) + 3e- → Al(s) E° = -1.66 V
Sn4+(aq) + 2e- → Sn2+(aq) E° = +0.14 V
I2(s) + 2e- → 2I-(aq) E° = +0.53 V
Which of the following is the strongest reducing agent? |
| | A) | Al3+(aq) |
| | B) | Al(s) |
| | C) | I-(aq) |
| | D) | I2(s) |
| | E) | Sn4+(aq) |
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| 8 | |
A redox reaction that involves the transfer of 3 electrons has a standard cell
potential of +0.34 V. Calculate ΔG° for this reaction (F = 96500 C/mol). |
| | A) | -98 kJ |
| | B) | -32 kJ |
| | C) | +98 kJ |
| | D) | +32 kJ |
| | E) | -8.3 kJ |
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| 9 | |
If the equilibrium constant Kc is greater than 1 for a given reaction, predict the signs of ΔG° and E° at the same temperature. |
| | A) | ΔG° > 0; E° > 0 |
| | B) | ΔG° < 0; E° < 0 |
| | C) | ΔG° > 0; E° < 0 |
| | D) | ΔG° < 0; E° > 0 |
| | E) | Cannot predict - it depends on the temperature. |
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| 10 | |
A voltaic cell consists of Mn/Mn2+ and Cd/Cd2+ half-cells. At 25°C the cell potential is +0.768 V when the concentration of Mn2+ ions is 0.500 M. Use the Nernst equation to calculate the Cd2+ concentration. Standard electrode potentials are given below.
(F = 96500 C/mol)
Cd2+(aq) + 2e- → Cd(s) E° = -0.402 V
Mn2+(aq) + 2e- → Mn(s) E° = -1.182 V |
| | A) | 0.010 M |
| | B) | 0.050 M |
| | C) | 0.20 M |
| | D) | 0.50 M |
| | E) | 0.25 M |
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| 11 | |
Which of the following statements about fuel cells is correct? |
| | A) | Fuel cells are electrolytic cells used to produce fuels such as H2. |
| | B) | Fuel cells are galvanic cells used to produce fuels such as H2. |
| | C) | Fuel cells are secondary cells. |
| | D) | Fuel cells have similar energy efficiency to electric power stations. |
| | E) | None of the above statements is correct. |
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| 12 | |
Which of the following statements about the corrosion of iron is incorrect? |
| | A) | Moisture is necessary in order for iron to corrode. |
| | B) | Oxygen acts as an oxidizing agent in iron corrosion. |
| | C) | Corrosion occurs more rapidly at high pH. |
| | D) | Corrosion occurs more rapidly in the presence of conducting solutions. |
| | E) | Corrosion of iron slows down when the iron is in contact with zinc metal. |
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| 13 | |
Which one of the following reactions must be carried out in an electrolytic cell, rather than a voltaic cell? |
| | A) | Zn + Cd2+ → Cd + Zn2+ |
| | B) | Al + 3/2Br2 → Al3+ + 3Br- |
| | C) | 2Al3+ + 3Fe → 2Al + 3Fe2+ |
| | D) | H2 + I2 → 2H+ + 2I- |
| | E) | 2H2 + O2 → 2H2O |
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| 14 | |
In an electrolytic cell, how many grams of Cu could be plated out of a
CuSO4 solution at a current of 5.00 A for 2.00 min? (F = 96500 C/mol) |
| | A) | 318 g |
| | B) | 0.395 g |
| | C) | 0.329 x 10-3 g |
| | D) | 0.198 g |
| | E) | 5.31 g |
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| 15 | |
How many minutes does it take to plate 0.800 g of silver metal onto a serving
tray from an aqueous solution of AgNO3 at a current of 2.50 A? (F = 96500 C/mol) |
| | A) | < 2 minutes |
| | B) | 2.38 minutes |
| | C) | 4.77 minutes |
| | D) | 9.54 minutes |
| | E) | 23.8 minutes |
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