Problem 63
Which metal cation is the best oxidizing agent? a. Pb2+ b. Cr3+ c. Fe2+ d. Sn2+
Problem 65b,c
Use tabulated electrode potentials to calculate ∆G°rxn for each reaction at 25 °C. b. Br2(l) + 2 Cl–(aq) → 2 Br–(aq) + Cl2(g) c. MnO2(s) + 4 H+(aq) + Cu(s) → Mn2+(aq) + 2 H2O(l) + Cu2+(aq)
Problem 66
Use tabulated electrode potentials to calculate ∆G°rxn for each reaction at 25 °C. a. 2 Fe3+(aq) + 3 Sn(s) → 2 Fe(s) + 3 Sn2+(aq) b. O2(g) + 2 H2O(l) + 2 Cu(s) → 4 OH–(aq) + 2 Cu2+(aq) c. Br2(l) + 2 I–(aq) → 2 Br–(aq) + I2(s)
Problem 67
Calculate the equilibrium constant for each of the reactions in Problem 65.
- Calculate the equilibrium constant for the reaction between Ni2+(aq) and Cd(s) at 25 °C.
Problem 69
Problem 70
Calculate the equilibrium constant for the reaction between Fe2+(aq) and Zn(s) (at 25 °C).
- Calculate ΔG°_rxn and E°_cell for a redox reaction with n = 2 that has an equilibrium constant of K = 25 (at 25 °C).
Problem 71
- Calculate ΔG°rxn and E°cell for a redox reaction with n = 3 that has an equilibrium constant of K = 0.050 (at 25 °C).
Problem 72
Problem 73
A voltaic cell employs the following redox reaction: Sn2+(aq) + Mn(s) → Sn(s) + Mn2+(aq) Calculate the cell potential at 25 °C under each set of conditions. c. [Sn2+] = 2.00 M; [Mn2+] = 0.0100 M
- A voltaic cell employs the redox reaction: 2 Fe3+(aq) + 3 Mg(s) → 2 Fe(s) + 3 Mg2+(aq). Calculate the cell potential at 25 °C under each set of conditions. a. standard conditions. b. [Fe3+] = 1.0 × 10^-3 M; [Mg2+] = 2.50 M. c. [Fe3+] = 2.00 M; [Mg2+] = 1.5 × 10^-3 M.
Problem 74
Problem 75
An electrochemical cell is based on these two half-reactions:
Ox: Pb(s) → Pb2+(aq, 0.10 M) + 2 e–
Red: MnO4–(aq, 1.50 M) + 4 H+(aq, 2.0 M) + 3 e– → MnO2(s) + 2 H2O(l)
Calculate the cell potential at 25 °C.
Problem 76
An electrochemical cell is based on these two half-reactions:
Ox: Sn(s) → Sn2+(aq, 2.00 M) + 2 e–
Red: ClO2(g, 0.100 atm) + e– → ClO2–(aq, 2.00 M)
Calculate the cell potential at 25 °C.
Problem 77a
A voltaic cell consists of a Zn/Zn2+ half-cell and a Ni/Ni2+ half-cell at 25 °C. The initial concentrations of Ni2+ and Zn2+ are 1.50 M and 0.100 M, respectively. a. What is the initial cell potential?
Problem 77b
A voltaic cell consists of a Zn/Zn2+ half-cell and a Ni/Ni2+ half-cell at 25 °C. The initial concentrations of Ni2+ and Zn2+ are 1.50 M and 0.100 M, respectively. b. What is the cell potential when the concentration of Ni2+ has fallen to 0.500 M?
Problem 77c
A voltaic cell consists of a Zn/Zn2+ half-cell and a Ni/Ni2+ half-cell at 25 °C. The initial concentrations of Ni2+ and Zn2+ are 1.50 M and 0.100 M, respectively. c. What are the concentrations of Ni2+ and Zn2+ when the cell potential falls to 0.45 V?
Problem 78a
A voltaic cell consists of a Pb/Pb2+ half-cell and a Cu/Cu2+ half-cell at 25°C. The initial concentrations of Pb2+ and Cu2+ are 0.0500 M and 1.50 M, respectively. a. What is the initial cell potential?
Problem 78b
A voltaic cell consists of a Pb/Pb2+ half-cell and a Cu/Cu2+ half-cell at 25°C. The initial concentrations of Pb2+ and Cu2+ are 0.0500 M and 1.50 M, respectively. b. What is the cell potential when the concentration of Cu2+ has fallen to 0.200 M?
Problem 78c
A voltaic cell consists of a Pb/Pb2+ half-cell and a Cu/Cu2+ half-cell at 25°C. The initial concentrations of Pb2+ and Cu2+ are 0.0500 M and 1.50 M, respectively. c. What are the concentrations of Pb2+ and Cu2+ when the cell potential falls to 0.35 V?
Problem 79
Make a sketch of a concentration cell employing two Zn/Zn2+ half-cells. The concentration of Zn2+ in one of the half-cells is 2.0 M and the concentration in the other half-cell is 1.0×10–3 M. Label the anode and the cathode and indicate the half-reaction occuring at each electrode. Also indicate the direction of electron flow.
Problem 80b
Consider the concentration cell: b. Indicate the direction of electron flow.
Problem 80c
Consider the concentration cell:
c. Indicate what happens to the concentration of Pb2+ in each half-cell.
Problem 81
A concentration cell consists of two Sn/Sn2+ half-cells. The cell has a potential of 0.10 V at 25°C. What is the ratio of the Sn2+ concentrations in the two half-cells?
Problem 82
A Cu/Cu2+ concentration cell has a voltage of 0.22 V at 25 °C. The concentration of Cu2+ in one of the half-cells is 1.5×10–3 M. What is the concentration of Cu2+ in the other half-cell? (Assume the concentration in the unknown cell is the lower of the two concentrations.)
Problem 83
Determine the optimum mass ratio of Zn to MnO2 in an alkaline battery.
Problem 84
What mass of lead sulfate is formed in a lead–acid storage battery when 1.00 g of Pb undergoes oxidation?
- Refer to the tabulated values of ∆Gf° in Appendix IIB to calculate E°cell for a fuel cell that employs the reaction between methane gas (CH4) and oxygen to form carbon dioxide and gaseous water.
Problem 85
Problem 86
Refer to the tabulated values of ∆G°f in Appendix IIB to calculate E°cell for the fuel-cell breathalyzer, which employs the following reaction. ((∆G° for HC2H3O2(g) = -374.2 kJ/mol.)
CH3CH2OH(g) + O2(g) → HC2H3O2(g) + H2O(g)
Problem 87a
Determine whether or not each metal, if coated onto iron, would prevent the corrosion of iron. a. Zn
Problem 87b
Determine whether or not each metal, if coated onto iron, would prevent the corrosion of iron. b. Sn
Problem 87c
Determine whether or not each metal, if coated onto iron, would prevent the corrosion of iron. c. Mn
Ch.20 - Electrochemistry