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www.tutor-homework.com (for tutoring, homework help, or help with online classes) 1. chem10b 20.

1 (for tutoring, homework help, or help with online classes) 1. chem10b In a voltaic cell electrons flow from the anode to the cathode. Value 2. chem10b How many grams of Cu are obtained by passing a current of 12 A through a solution of CuSO4 for 15 minutes? A. 7.1 B. 3.6 C. 14 D E chem10b The standard reduction potential of X is 1.23 V and that of Y is V therefore X is oxidized by Y. Value 4. chem10b What is the anode in an alkaline battery?

2 A. MnO 2 B. Zn powder C. KOH D. Mn 2 O 3 E. Pt 5. chem10b The standard cell potential (E ) of a voltaic cell constructed using the cell reaction below is 0.76 V: Zn (s) + 2H + (aq) Zn 2+ (aq) + H 2 (g) With P H2 = 1.0 atm and [Zn 2+ ] = 1.0 M, the cell potential is 0.66 V. The concentration of H + in the cathode compartment is M. tudent Response Correct Answer A B C D E chem10b Table 20.2 The standard cell potential (E cell ) for the voltaic cell based on the reaction below is V. 2Cr (s) + 3Fe 2+ (aq) 3Fe (s) + 2Cr 3+ (aq)

3 A B C D E chem10b In a voltaic cell, electrons flow fromthe to the. A. salt bride, anode B. anode, salt bridge C. cathode, anode D. salt bridge, cathode E. anode, cathode 8. chem10b The balanced half-reaction in which dichromate ion is reduced to chromium metal is a process. A. three-electron B. four-electron C. twelve-electron D. two-electron E. six-electron Score: 1/1 9. chem10b The purpose of the salt bridge in an electrochemical cell is to.

4 A. provide oxygen to facilitate oxidation at the anode. B. provide a source of ions to react at the anode and cathode. C. provide a means for electrons to travel from the cathode to the anode. D. maintain electrical neutrality in the half-cells via migration of ions. E. provide a means for electrons to travel from the anode to the cathode. 10. chem10b The electrode at which oxidation occurs is called the. A. reducing agent B. anode C. voltaic cell D. oxidizing agent E. cathode 11. chem10b Table 20.2 Which of the following reactions will occur spontaneously as written? A. Sn 4+ (aq) + Fe 3+ (aq) Sn 2+ (aq) + Fe 2+ (aq) B. Sn 4+ (aq) + Fe 2+ (aq) Sn 2+ (aq) + Fe (s) C. 3Sn 4+ (aq) + 2Cr (s) 2Cr 3+ (aq) + 3Sn 2+ (aq)

5 D. 3Fe (s) + 2Cr 3+ (aq) 2Cr (s) + 3Fe 2+ (aq) E. 3Fe 2+ (aq) Fe (s) + 2Fe 3+ (aq) 12. chem10b What is the coefficient of Fe 3+ when the following equation is balanced? CN - + Fe 3+ CNO - + Fe 2+ (basic solution) A. 1 B. 2 C. 3 D. 4 E chem10b What is the oxidation number of potassium in KMnO 4? A. +1 B. -1 C. 0 D. +3 E chem10b Table 20.2

6 The standard cell potential (E cell ) for the voltaic cell based on the reaction below is V. Sn 2+ (aq) + 2Fe 3+ (aq) 2Fe 2+ (aq) + Sn 4+ (aq) A B C D E chem10b Which one of the following is the best oxidizing agent? A. Ca B. O 2 C. Na D. Li E. H 2 4. chem10b Disadvantages of the methanol fuel cell compared to the hydrogen fuel cell are consumption of catalyst and environmentally safe product. Value

7 5. chem10b Corrosion of iron is retarded by. A. the presence of salts B. low ph conditions C. high ph conditions D. both the presence of salts and high ph conditions E. both the presence of salts and low ph conditions 6. chem10b V =. A C B. 1 J/C C. 1 J/s D. 1 C/J E. 1 amp s Score: 1/1 7. chem10b In a half reaction the amount of a substance that is reduced or oxidized is directly proportional to the number of electrons generated in the cell. Value 8. chem10b Table 20.2

8 Which of the following reactions will occur spontaneously as written? A. Sn 4+ (aq) + Fe 2+ (s) Sn 2+ (aq) + Fe (s) B. Sn 2+ (aq) + Fe 2+ (s) Sn 4+ (aq) + Fe 3+ (aq) C. 2Cr (s) + 3Fe 2+ (s) 3Fe (s) + 2Cr 3+ (aq) D. 2Cr 3+ (aq) + 3Sn 2+ (aq) 3Sn 4+ (aq) + 2Cr (s) E. 3Fe 2+ (aq) + Cr 3+ (aq) Cr (s) + 3Fe 3+ (aq) 9. chem10b The lead-containing reactant(s) consumed during recharging of a lead-acid battery is/are. A. Pb (s) only B. PbSO 4 (s) only C. PbO 2 (s) only D. both PbO 2 (s) and PbSO 4 (s) E. both Pb (s) and PbO 2 (s) 10. chem10b The gain of electrons by an element is called. A. fractionation B. disproportionation C. oxidation

9 D. sublimation E. reduction 11. chem10b is the oxidizing agent in the reaction below. Cr 2 O S 2 O H + 2Cr S 4 O H 2 O 2- A. S 4 O 6 B. Cr C. S 2 O 3 D. H + 2- E. Cr 2 O chem10b Which one of the following reactions is a redox reaction? A. AgNO 3 + HCl HNO 3 + AgCl B. NaOH + HCl NaCl + H 2 O C. Pb Cl - PbCl 2 D. H 2 O + NaCl NaOH + HCl E. None of the above is a redox reaction. 1. chem10b A positive number for maximum useful work in a spontaneous process (voltaic cell) indicates that the cell will perform work on its surroundings. Value

10 2. chem10b electrons appear in the following half-reaction when it is balanced. S 4 O 6 2-2S 2 O 3 2- A. 6 B. 2 C. 3 D. 4 E chem10b What is the anode in an alkaline battery? A. MnO 2 B. Pt C. KOH D. Mn 2 O 3 E. Zn powder 4. chem10b The half-reaction occurring at the anode in the balanced reaction shown below is. 3MnO 4 - (aq) + 24H + (aq) + 5Fe (s) 3Mn 2+ (aq) + 5Fe 3+ (aq) + 12H 2 O (l) A. Fe (s) Fe 2+ (aq) + 2e - B. 2MnO 4 - (aq) + 12H + (aq) + 6e - 2Mn 2+ (aq) + 3H 2 O (l)

11 C. Fe (s) Fe 3+ (aq) + 3e - D. MnO 4 - (aq) + 8H + (aq) + 5e - Mn 2+ (aq) + 4H 2 O (l) E. Fe 2+ (aq) Fe 3+ (aq) + e - 5. chem10b The gain of electrons by an element is called. A. oxidation B. disproportionation C. reduction D. fractionation E. sublimation 6. chem10b How many minutes will it take to plate out 2.19 g of chromium metal from a solution of Cr 3+ using a current of 35.2 amps in an electrolyte cell? A B C. 115 D E. 346 Score: 1/1 7. chem10b The balanced half-reaction in which chlorine gas is reduced to the aqueous chloride ion is a process. A. six-electron

12 B. three-electron C. one-electron D. four-electron E. two-electron 8. chem10b The more the value of E red, the greater the driving force for reduction. A. extensive B. negative C. exothermic D. positive E. endothermic Score: 1/1 9. chem10b The electrode at which oxidation occurs is called the. A. oxidizing agent B. anode C. voltaic cell D. reducing agent E. cathode 10. chem10b In a voltaic cell electrons flow from the anode to the cathode. Value

13 11. chem10b Galvanized iron is iron coated with. A. phosphate. B. magnesium. C. iron oxide. D. chromium. E. zinc. 12. chem10b The standard cell potential (E cell ) for the reaction below is V. The cell potential for this reaction is V when the concentration of [Cu 2+ ] = 1.0x10^-5 M and [Zn 2+ ] = 1.0 M Zn (s) + Cu 2+ (aq) Cu (s) + Zn 2+ (aq) A B C D E chem10b Which substance is the reducing agent in the reaction below? Pb + PbO 2 + 2H 2 SO 4 2PbSO 4 + 2H 2 O A. Pb B. H 2 O C. PbSO 4

14 D. H 2 SO 4 E. PbO chem10b The standard reduction potential,, is proportional to the stoichiometric coefficient. Value 15. chem10b What is the oxidation number of chromium in Cr 2 O 7-2 ion? A. +7 B. +3 C. +12 D. +14 E chem10b Table 20.2 The standard cell potential (E cell ) for the voltaic cell based on the reaction below is V. Sn 2+ (aq) + 2Fe 3+ (aq) 2Fe 2+ (aq) + Sn 4+ (aq)

15 A B C D E chem10b How many grams of copper will be plated out by a current of 2.3 A applied for 25 minutes to a 0.50-M solution of copper(ii) sulfate? A B. 1.1 C D. 2.2 E chem10b The balanced half-reaction in which sulfate ion is reduced to sulfite ion is a process. A. four-electron B. six-electron C. three-electron D. two-electron E. one-electron 19. chem10b The lead-containing reactant(s) consumed during recharging of a lead-acid battery is/are.

16 A. Pb (s) only B. PbSO 4 (s) only C. PbO 2 (s) only D. both PbO 2 (s) and PbSO 4 (s) E. both Pb (s) and PbO 2 (s) 20. chem10b One of the differences between a voltaic cell and an electrolytic cell is that in an electrolytic cell. A. O 2 gas is produced at the cathode B. a nonspontaneous reaction is forced to occur C. electrons flow toward the anode D. oxidation occurs at the cathode E. an electric current is produced by a chemical reaction 1. chem10b The relationship between the change in Gibbs free energy and the emf of an electrochemical cell is given by. A. ΔG = -nf/(ert) B. ΔG = -nrtf C. ΔG = -E/(nF) D. ΔG = -nf/e E. ΔG = -nfe

17 2. chem10b One of the differences between a voltaic cell and an electrolytic cell is that in an electrolytic cell. A. electrons flow toward the anode B. a nonspontaneous reaction is forced to occur C. O 2 gas is produced at the cathode D. an electric current is produced by a chemical reaction E. oxidation occurs at the cathode 3. chem10b Which transformation could take place at the anode of an electrochemical cell? A. CO 2 C 2 O 4 2- B. O 2 H 2 O 2 C. NO NO 3 - D. VO 2 + VO 2+ E. H 2 AsO 4 H 3 AsO 3 4. chem10b The town of Natrium, West Virginia, derives its name from the sodium produced in the electrolysis of molten sodium chloride (NaCl) mined from ancient salt deposits. The number of kilowatt-hours of electricity required to produce 4.60 kg of metallic sodium from the electrolysis of molten NaCl(s) is when the applied emf is 4.50 V. A B C D E. 24.1

18 5. chem10b Table 20.1 Half Reaction E (V) F 2 (g) + 2e - 2F - (aq) Cl 2 (g) + 2e - 2Cl - (aq) Br 2 (l) + 2e - 2Br - (aq) O 2 (g) + 4H + (aq) + 4e - 2H 2 O (l) Ag + + e - Ag (s) Fe 3+ (aq) + e - Fe 2+ (aq) I 2 (s) + 2e - 2I - (aq) Cu e - Cu (s) H + + 2e - H 2 (g) 0 Pb e - Pb (s) Ni e - Ni (s) Li + + e - Li (s) Using Table 20.1, which substance can oxidize I - (aq) to I 2 (s)? A. Ag (s) B. Ni 2+ (aq) C. Cu 2+ (aq) D. Br - (aq) E. Br 2 (l) 6. chem10b V =. A. 1 amp s B C C. 1 C/J D. 1 J/C E. 1 J/s 7. chem10b

19 The standard emf for the cell using the overall cell reaction below is V: Zn (s) + Ni 2+ (aq) Zn 2+ (aq) + Ni (s) The emf generated by the cell when [Ni 2+ ] = 2.50 M and [Zn 2+ ] = M is A B C D E chem10b A positive number for maximum useful work in a spontaneous process (voltaic cell) indicates that the cell will perform work on its surroundings. Value 9. chem10b The balanced half-reaction in which sulfate ion is reduced to sulfite ion is a process. A. two-electron B. four-electron C. six-electron D. one-electron E. three-electron Score: 1/1 10. chem10b

20 Consider an electrochemical cell based on the reaction: 2H + (aq) + Sn (s) Sn 2+ (aq) + H 2 (g) Which of the following actions would change the measured cell potential? A. increasing the pressure of hydrogen gas in the cathode compartment B. increasing the ph in the cathode compartment C. increasing the [Sn 2+ ] in the anode compartment D. lowering the ph in the cathode compartment E. Any of the above will change the measure cell potential. 11. chem10b The standard cell potential (E cell ) for the reaction below is V. The cell potential for this reaction is V when [ Zn 2+ ] = 1.0 M and [Pb 2+ ] = Pb 2+ (aq) + Zn (s) Zn 2+ (aq) + Pb (s) A B C D E chem10b is the oxidizing agent in the reaction below. Cr 2 O S 2 O H + 2Cr S 4 O H 2 O A. H +

21 2- B. S 2 O 3 2- C. Cr 2 O 7 2- D. S 4 O 6 E. Cr chem10b Table 20.2 The standard cell potential (E cell ) for the voltaic cell based on the reaction below is V. Cr (s) + 3Fe 3+ (aq) 3Fe 2+ (aq) + Cr 3+ (aq) A B C D E chem10b The balanced half-reaction in which chlorine gas is reduced to the aqueous chloride ion is a process. A. four-electron B. one-electron

22 C. six-electron D. three-electron E. two-electron 3. chem10b The reduction half reaction occurring in the standard hydrogen electrode is. A. H 2 (g, 1 atm) 2H + (aq, 1M) + 2e - B. 2H + (aq, 1M) + 2e - H 2 (g, 1 atm) C. O 2 (g) + 4H + (aq) + 4e - 2H 2 O (l) D. 2H + (aq) + 2OH - H 2 O (l) E. 2H + (aq, 1M) + Cl 2 (aq) 2HCl (aq) 4. chem10b One of the differences between a voltaic cell and an electrolytic cell is that in an electrolytic cell. A. an electric current is produced by a chemical reaction B. O 2 gas is produced at the cathode C. oxidation occurs at the cathode D. electrons flow toward the anode E. a nonspontaneous reaction is forced to occur 5. chem10b Which one of the following types of elements is most likely to be a good oxidizing agent? A. alkaline earth elements B. halogens

23 C. lanthanides D. transition elements E. alkali metals 6. chem10b How many grams of Ca metal are produced by the electrolysis of molten CaBr 2 using a current of 30.0 amp for 10.0 hours? A B. 112 C. 224 D E chem10b How many grams of Cu are obtained by passing a current of 12 A through a solution of for 15 minutes? A. 7.1 B. 14 C. 3.6 D. 1.8 E chem10b Which transformation could take place at the anode of an electrochemical cell?

24 A. NO NO 3 - B. O 2 H 2 O 2 C. CO 2 C 2 O 4 2- D. H 2 AsO 4 H 3 AsO 3 E. VO 2 + VO chem10b Table 20.1 Half Reaction E (V) F 2 (g) + 2e - 2F - (aq) Cl 2 (g) + 2e - 2Cl - (aq) Br 2 (l) + 2e - 2Br - (aq) O 2 (g) + 4H + (aq) + 4e - 2H 2 O (l) Ag + + e - Ag (s) Fe 3+ (aq) + e - Fe 2+ (aq) I 2 (s) + 2e - 2I - (aq) Cu e - Cu (s) H + + 2e - H 2 (g) 0 Pb e - Pb (s) Ni e - Ni (s) Li + + e - Li (s) Using Table 20.1, which substance can be oxidized by O 2 (g) in acidic aqueous solution? A. Ag (s) B. Br 2 (l) C. Br - (aq) D. Ni 2+ (aq) E. Cu 2+ (aq) 10. chem10b Table 20.2

25 Which of the following reactions will occur spontaneously as written? A. 2Cr 3+ (aq) + 3Sn 2+ (aq) 3Sn 4+ (aq) + 2Cr (s) B. 3Fe 2+ (aq) + Cr 3+ (aq) Cr (s) + 3Fe 3+ (aq) C. Sn 4+ (aq) + Fe 2+ (s) Sn 2+ (aq) + Fe (s) D. Sn 2+ (aq) + Fe 2+ (s) Sn 4+ (aq) + Fe 3+ (aq) E. 2Cr (s) + 3Fe 2+ (s) 3Fe (s) + 2Cr 3+ (aq) 11. chem10b What is the anode in an alkaline battery? A. Zn powder B. KOH C. MnO 2 D. Pt E. Mn 2 O chem10b Which substance is the reducing agent in the following reaction? Fe 2 S HNO 3 2Fe(NO 3 ) 3 + 3S + 6NO 2 + 6H 2 O A. H 2 O B. NO 2 C. S D. HNO 3 E. Fe 2 S 3

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

A.P. Chemistry Practice Test - Ch. 17: Electochemistry MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) The gain of electrons by an element is called.