Galvanic and electrolytic cells, cell potential and electrolysis

Learning objectives

Label a galvanic cell, identifying the anode, the cathode, the direction of electron flow in the external circuit and the direction of ion migration through the salt bridge, and write the half-reactions

Calculate standard cell potential from standard reduction potentials, and use the sign of E°cell to decide whether a redox reaction is thermodynamically favored

Relate ΔG° to E°cell through ΔG° = −nFE°cell, and connect both to the equilibrium constant of the cell reaction

Predict the effect of changing concentration on cell potential by comparing Q with K (Le Châtelier arguments do not apply to a working cell, and the Nernst equation is beyond the exam), and explain why a cell potential falls to zero as the cell reaches equilibrium

Distinguish an electrolytic from a galvanic cell, and use Faraday's relationship between charge, current, time and moles of electrons to calculate the mass of substance deposited or the time required