Electrode potentials and electrochemical cells

negative electrode where oxidation takes place

Negative electrode where reduction takes place

Combination of two half cells, consists of two electron conductors (electrodes) separated by an ionic conductor (electrolyte). Cells are used to measure electrode potentials by reference to the standard hydrogen electrode

A series of elements arranged in order of their standard electrode potentials

A conductor through which electricity enters or leaves a substance or region

The potential difference of a cell consisting of a specific electrode as the cathode and the standard hydrogen electrode as the anode. Reduction always takes place at the cathode, and oxidation at the anode

The difference between the potential differences of the cathode and anode in an electrochemical cell

An electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidising agent (often oxygen) into electricity through redox reactions. They do not need to be recharged

A cell that is designed to be used only once since the reactions involved are irreversible

cells in which reversible reactions occur, allowing them to be recharged to regain their cell potential

A reaction in which reduction and oxidation occur simultaneously

A porous substance soaked with a solution of an inert, strong electrolyte, e.g. a filter paper soaked in KNO3(aq). The salt ions flow through the bridge to complete the cell and balance charges in solutions

• Li (s) → Li+ (s) + e– • Li+ (s) + CoO2 (s) + e– → LiCoO2 (s)

• O2(g) + 2H2O(l) + 4e⁻ → 4OH⁻(aq) Eꝋ = +0.40 V • 2H2O(l) + 2e⁻ → H2(g) + 2OH⁻(aq) Eꝋ = -0.83 V