Extent of reaction

The extent of reaction is a concept used in chemical thermodynamics and reaction kinetics to quantify the progress of a chemical reaction. It is often denoted by the symbol \( \xi \) (xi) and represents the amount by which a reaction has proceeded relative to its stoichiometry. Mathematically, the extent of reaction is defined as a variable that describes the change in the number of moles of reactants and products during a reaction.