Electrochemistry Practice
1. A 3.50-A current is used to produce nickel metal from a solution containing Ni2+ ions. What mass
of nickel is produced in 15.0 minutes?
2. A U.S. penny consists of a slug of zinc upon which a thin plate of copper is applied through an
electroplating process. Consider a company that has a government contract to electroplate the
pennies. The government specifications require a minimum mass of 62.5 mg of copper on each
penny. The company immerses the pennies in a solution of Cu(CN)2 for 3.25 minutes. What
current would be required to meet the government’s minimum mass requirement?
3. For the following redox reaction where all ion concentrations are 1.00 M.:
2 Fe(s) + 3 Sn4+(aq) → 2 Fe3+(aq) + 3 Sn2+(aq)
a. Determine the reduction half-equation.
b. Determine the oxidation half-equation.
c. Determine the E° value for the cathode half-cell (i.e., Ered°).
d. Determine the E° value for the anode half-cell (i.e., Eox°).
e. Determine the overall cell voltage.
4. Consider the following redox reaction occurring in a Galvanic cell at standard conditions:
Cu(s) + 2 Fe3+(aq) → Cu2+(aq) + 2 Fe2+(aq)
a. Use the Table of Standard Reduction Potentials to calculate the cell voltage for this reaction
at standard conditions.
b. Suppose all ion concentrations are 0.145 M. Calculate the reaction quotient for these
conditions.
c. Determine the cell voltage with these non-standard concentrations at 25°C.
5. A galvanic cell is made by placing aluminum metal and chromium metal in a solution of their
respective ions - Al3+ and Cr3+. If the concentrations of each of the ions is 0.25 M, determine the
cell voltage and write the line notation for the resulting galvanic cell.
6. A Galvanic cell is based on the following two half-reactions, written here as reduction reactions.
The corresponding standard reduction potential is listed.
S2O82-(aq) + 2 e- → 2 SO42-(aq)
Ag+(aq) + e- → Ag(s)
E° = 2.01 V
E° = 0.80 V
The balanced equation for the Galvanic cell is
S2O82-(aq) + 2 Ag(s) → 2 SO42-(aq) + 2 Ag+(aq)
a. Determine the cell voltage of the Galvanic cell. Assume standard conditions.
b. Use the cell voltage to determine the Gibbs free energy change (in kJ) for this reaction.
7. Calculate cell potential for a concentration cell with two silver electrodes with concentrations 0.2
M and 3.0 M.