Practice identifying anodes, cathodes, electron flow, cell notation, standard cell potential, and basic electrolysis calculations for galvanic and electrolytic cells.
Read each problem carefully. Show your work in the space provided. Use proper units and labels when calculations are required.
Comparing spontaneous and nonspontaneous redox reactions in cells
Chemistry - Grade 9-12
- 1
A galvanic cell is made from Zn and Cu electrodes. The half-reactions are Zn2+ + 2e- -> Zn with E° = -0.76 V and Cu2+ + 2e- -> Cu with E° = +0.34 V. Identify the anode, the cathode, and the direction of electron flow.
- 2
Using the Zn and Cu standard reduction potentials, calculate the standard cell potential for the cell Zn(s) | Zn2+(aq) || Cu2+(aq) | Cu(s).
- 3
Write the balanced overall reaction for the galvanic cell Zn(s) | Zn2+(aq) || Cu2+(aq) | Cu(s).
- 4
Explain the purpose of the salt bridge in a galvanic cell.
- 5
A student builds a cell with Fe and Ag electrodes. The standard reduction potentials are Fe2+ + 2e- -> Fe with E° = -0.44 V and Ag+ + e- -> Ag with E° = +0.80 V. Identify which substance is oxidized and which ion is reduced.
- 6
For the Fe and Ag cell in problem 5, write the balanced overall reaction and calculate E°cell.
- 7
Classify each cell as galvanic or electrolytic: Cell A produces electrical energy from a spontaneous redox reaction. Cell B uses a battery to force a nonspontaneous redox reaction.
- 8
In an electrolytic cell containing molten sodium chloride, Na+ ions move toward one electrode and Cl- ions move toward the other. Identify what happens at the cathode and at the anode.
- 9
Compare the signs of the electrodes in galvanic and electrolytic cells.
- 10
A current of 2.00 A passes through a copper(II) sulfate solution for 20.0 minutes. Copper is plated according to Cu2+ + 2e- -> Cu. Calculate the mass of copper plated. Use F = 96,485 C/mol e- and molar mass of Cu = 63.55 g/mol.
- 11
A current of 5.00 A runs through molten MgCl2 for 30.0 minutes. Magnesium forms according to Mg2+ + 2e- -> Mg. Calculate the mass of magnesium produced. Use F = 96,485 C/mol e- and molar mass of Mg = 24.31 g/mol.
- 12
A cell has E°cell = -0.50 V as written. Explain whether the reaction is spontaneous as written and describe one way to make it occur in an electrolytic cell.