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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
Problem 88a
Determine whether or not each metal, if coated onto iron, would prevent the corrosion of iron. a. Mg
Problem 88b
Determine whether or not each metal, if coated onto iron, would prevent the corrosion of iron. b. Cr
Problem 88c
Determine whether or not each metal, if coated onto iron, would prevent the corrosion of iron. c. Cu
Problem 89b
Consider the electrolytic cell: b. Indicate the direction of electron flow.
Problem 90
Draw an electrolytic cell in which Mn2+ is reduced to Mn and Sn is oxidized to Sn2+. Label the anode and cathode, indicate the direction of electron flow, and write an equation for the half-reaction occurring at each electrode. What minimum voltage is necessary to drive the reaction?
Problem 91
Write equations for the half-reactions that occur in the electrolysis of molten potassium bromide.
Problem 92
What products are obtained in the electrolysis of molten NaI?
- Write equations for the half-reactions that occur in the electrolysis of a mixture of molten potassium bromide and molten lithium bromide.
Problem 93
Problem 94
What products are obtained in the electrolysis of a molten mixture of KI and KBr?
Problem 95
Write equations for the half-reactions that occur at the anode and cathode for the electrolysis of each aqueous solution. a. NaBr(aq) b. PbI2(aq) c. Na2SO4(aq)
Problem 96a
Write equations for the half-reactions that occur at the anode and cathode for the electrolysis of each aqueous solution. a. Ni(NO3)2(aq)
Problem 96b,c
Write equations for the half-reactions that occur at the anode and cathode for the electrolysis of each aqueous solution. b. KCl(aq) c. CuBr2(aq)
Problem 97
Make a sketch of an electrolysis cell that electroplates copper onto other metal surfaces. Label the anode and the cathode and indicate the reactions that occur at each.
- How can one sketch an electrolysis cell that electroplates nickel onto other metal surfaces, labeling the anode and cathode and indicating the reactions that occur at each?
Problem 98
- Copper can be electroplated at the cathode of an electrolysis cell by the half-reaction: Cu2+(aq) + 2 e- → Cu(s). How much time would it take for 325 mg of copper to be plated at a current of 5.6 A?
Problem 99
Problem 100
Silver can be electroplated at the cathode of an electrolysis cell by the half-reaction: Ag+(aq) + e– → Ag(s) What mass of silver would plate onto the cathode if a current of 6.8 A flowed through the cell for 72 min?
Problem 101
A major source of sodium metal is the electrolysis of molten sodium chloride. What magnitude of current produces 1.0 kg of sodium metal in 1 hour?
- What mass of aluminum metal can be produced per hour in the electrolysis of a molten aluminum salt using a current of 25 A?
Problem 102
- Consider the reaction shown here occurring at 25 °C: A(s) + B2+(aq) → A2+(aq) + B(s). Given that ∆Gr°xn = -14.0 kJ, determine the value of Ec°ell and K for the reaction, and complete the following table for [B2+], [A2+], Q, Ecell, and ∆Grxn with initial values 1.00, 1, 1.0 * 10^-4, 3.54 * 10^-3, and 1.00 * 10^-4 respectively.
Problem 103
Problem 104
Consider the reaction shown here occurring at 25°C. Cr(s) + Cd2+(aq) → Cr2+(aq) + Cd(s) Determine E°cell, K, and ∆G°rxn for the reaction and complete the table.
[Cd2+] [Cr2+] Q Ecell 𝚫Grxn
1.00 1.00
1.00 1.00 × 10-5
1.00 × 10-5 1.00
4.18 × 10-4 1.00
- Consider the unbalanced redox reaction: MnO4-(aq) + Zn(s) → Mn2+(aq) + Zn2+(aq). Balance the equation and determine the volume of a 0.500 M KMnO4 solution required to completely react with 2.85 g of Zn.
Problem 105