1. General Chemistry Principles & Modern Applications 9 th Edition Petrucci/Harwood/Herring/Madura Chapter 20 Electrochemistry Dr. Travis D. Fridgen Memorial University of Newfoundland © 2007 Pearson Education

2. What is the oxidation state of Cr in ? potassium dichromate 1. +8 2. +7 3. +6 4. -1 5. -2

3. What is the oxidation state of Cr in ? potassium dichromate 1. +8 2. +7 3. +6 4. -1 5. -2

4. When a piece of copper metal is put into a solution of silver nitrate (AgNO 3 ), silver metal is produced along with Cu 2+, the latter of which is responsible for the blue color of the solution. Which of the following statements is false? 1.  G for the reaction is negative (the reaction is exergonic). 3. Cu is oxidized. 2.For every mole of Cu reacted, two moles of Ag is produced. 4. Ag is an oxidizing agent. 5. A solution of CuSO 4 will be blue.

5. When a piece of copper metal is put into a solution of silver nitrate (AgNO 3 ), silver metal is produced along with Cu 2+, the latter of which is responsible for the blue color of the solution. Which of the following statements is false? 1.  G for the reaction is negative (the reaction is exergonic). 3. Cu is oxidized. 2.For every mole of Cu reacted, two moles of Ag is produced. 4. Ag is an oxidizing agent. 5. A solution of CuSO 4 will be blue.

6. 1.8 x 10 -4 M Pb(NO 3 ) 2 0.25 M KI Pb(s), PbI 2 (s)Pb(s) For the electrochemical cell depicted to the right, which of the following is correct the shorthand notation?

7. 1.8 x 10 -4 M Pb(NO 3 ) 2 0.25 M KI Pb(s), PbI 2 (s)Pb(s) For the electrochemical cell depicted to the right, which of the following is correct the shorthand notation?

8. Given the following standard electrode potentials, Which of the following is spontaneous?

9. Given the following standard electrode potentials, Which of the following is spontaneous?

10. A voltaic cell was produced based on the following overall reaction. The emf was measured to be 0.21 V. E o cell is -1.10 V. Which of the following three statements is false? 1.When [Zn 2+ ] and [Cu 2+ ] = 1.00 M  G > 0 Zn Zn(NO 3 ) 2 (aq) Cu 0.21 V CuSO 4 (aq) 2.[Cu 2+ ] must be far greater than [Zn 2+ ] 3.  G 0.

11. A voltaic cell was produced based on the following overall reaction. The emf was measured to be 0.21 V. E o cell is -1.10 V. Which of the following three statements is false? 1.When [Zn 2+ ] and [Cu 2+ ] = 1.00 M  G > 0 Zn Zn(NO 3 ) 2 (aq) Cu 0.21 V CuSO 4 (aq) 2.[Cu 2+ ] must be far greater than [Zn 2+ ] 3.  G 0.

12. Given the two electrochemical cells to the right, a cell constructed according to the following shorthand notation 1. 1.103 2. 0.423 has a cell potential of: 3. -0.423 4. -1.103

13. Given the two electrochemical cells to the right, a cell constructed according to the following shorthand notation has a cell potential of: 1. 1.103 2. 0.423 3. -0.423 4. -1.103

14. Given the electrochemical cells to the right, what would be the cell potential for the electrochemical cell constructed as indicated by the following shorthand notation? 2. 1.563 3. 0.643 4. -0.643 5. -1.563 1. 2.023

15. Given the electrochemical cells to the right, what would be the cell potential for the electrochemical cell constructed as indicated by the following shorthand notation? 2. 1.563 3. 0.643 4. -0.643 5. -1.563 1. 2.023

16. Which of the following would result in an increase in the cell potential? 1. Decreasing [Ag + ] in the cathode. 2. Decreasing [Fe 2+ ] in the anode. 3. Decreasing [Fe 3+ ] in the anode. 4. Adding NaCl to the cathode. 5. Increasing [KNO 3 ] in the salt bridge.

17. Which of the following would result in an increase in the cell potential? 1. Decreasing [Ag + ] in the cathode. 2. Decreasing [Fe 2+ ] in the anode. 3. Decreasing [Fe 3+ ] in the anode. 4. Adding NaCl to the cathode. 5. Increasing [KNO 3 ] in the salt bridge.

18. Which of the following is false for the electrolysis of water? 1.Water is oxidized to form oxygen at the anode. 2.Water is reduced to form hydrogen at the cathode. 3.The electrode marked A is the cathode and that marked B is the anode. AB 4.The hydrolysis of water is non-spontaneous and requires the input of energy from an external source.

19. Which of the following is false for the electrolysis of water? 1.Water is oxidized to form oxygen at the anode. 2.Water is reduced to form hydrogen at the cathode. 3.The electrode marked A is the cathode and that marked B is the anode. AB 4.The hydrolysis of water is non-spontaneous and requires the input of energy from an external source.

20. When pure iron is put into pure water, it produces H 2 gas, and when pure iron is put into an acidic solution it produces H 2 gas. Using the data below, state whether the above statement is true or false. 1. True2. False

21. When pure iron is put into pure water, it produces H 2 gas, and when pure iron is put into an acidic solution it produces H 2 gas. Using the data below, state whether the above statement is true or false. 1. True2. False

22. Pb(NO 3 ) 2 (0.1M)Al(NO 3 ) 3 (0.5M) E cell PbAl KNO 3 The Nernst equation for the electrochemical cell depicted to the right is:

23. Pb(NO 3 ) 2 (0.1M)Al(NO 3 ) 3 (0.5M) E cell PbAl KNO 3 The Nernst equation for the electrochemical cell depicted to the right is:

24. Cr(NO 3 ) 3 Mn(NO 3 ) 2 CrMn KNO 3 In the electrochemical cell to the right the concentrations of Mn 2+ and Cr 3+ are 0.010 M and 0.10 M, respectively. What is the cell potential? Use the equation to the right and do not use a calculator. Do use a pen and paper! 1. 0.48 V 2. 0.45 V 2. 0.44 V 4. 0.43 V 5. 0.40 V

25. Cr(NO 3 ) 3 Mn(NO 3 ) 2 CrMn KNO 3 In the electrochemical cell to the right the concentrations of Mn 2+ and Cr 3+ are 0.010 M and 0.10 M, respectively. What is the cell potential? Use the equation to the right and do not use a calculator. Do use a pen and paper! 1. 0.48 V 2. 0.45 V 2. 0.44 V 4. 0.43 V 5. 0.40 V

26. Which of the following would be produced in the largest abundance by mass by the consumption of 1 kW hour of electricity? 4. Ag from a solution of Ag + 2. Cu from a solution of Cu + 1. Ni from a solution of Ni 3+ 5. Cd from a solution of Cd 2+ 3. Zn from a solution of Zn 2+ CuZn Cd Ni Ag 2930 4847 28 63.45665.39 112.411107.868 58.69 111210

27. Which of the following would be produced in the largest abundance by mass by the consumption of 1 kW hour of electricity? 4. Ag from a solution of Ag + 2. Cu from a solution of Cu + 1. Ni from a solution of Ni 3+ 5. Cd from a solution of Cd 2+ 3. Zn from a solution of Zn 2+ CuZn Cd Ni Ag 2930 4847 28 63.45665.39 112.411107.868 58.69 111210