(A Level) Electrochemistry: electrolysis, electrode potentials and the Nernst equation

Learning objectives

Predict the products of electrolysis of molten and aqueous electrolytes from electrode potentials and concentration, and calculate the mass or volume of product using Q = It and F = Le

Describe how the Avogadro constant can be found by electrolysis, e.g. by weighing a copper electrode before and after passing a measured current for a measured time

Describe the standard hydrogen electrode and how standard electrode potentials are measured for metal/ion, non-metal/ion and ion/ion systems using a platinum electrode and a salt bridge

Calculate E⦵cell from two electrode potentials, deduce the polarity of each electrode and the direction of electron flow, and predict the feasibility of redox reactions and the relative strength of oxidising and reducing agents

Use the Nernst equation E = E⦵ + (0.059/z) log([oxidised form]/[reduced form]) to calculate how electrode potentials such as Cu²⁺/Cu and Fe³⁺/Fe²⁺ change with concentration

Construct redox equations from half-equations and link cell potential to free energy with ΔG⦵ = −nE⦵cellF