Electrode potentials and electrochemical cells (A-level only)

Electrode potentials and electrochemical cells form a core part of AQA A-Level Chemistry, bridging physical and inorganic chemistry. This topic explores how the tendency of a species to gain or lose electrons can be measured and used to predict the direction of redox reactions. You'll learn to construct electrochemical cells, measure standard electrode potentials, and use them to calculate cell potentials (EMF) under standard conditions. Understanding this allows you to predict whether a reaction is feasible and to design cells that generate electricity, such as batteries and fuel cells.

The topic is crucial for explaining real-world applications like corrosion prevention (sacrificial protection), the operation of rechargeable batteries, and the function of hydrogen-oxygen fuel cells. It also introduces the concept of the electrochemical series, which ranks species by their reducing or oxidising power. Mastery of this area requires a solid grasp of redox reactions, equilibrium, and thermodynamics, as electrode potentials are essentially a measure of thermodynamic tendency. This knowledge is assessed through both calculations and explanations of cell diagrams, including the use of salt bridges and standard conditions.