Why do chemists write half-reactions to express reduction potentials?

Chemists write half-reactions to express reduction potentials primarily to clearly show electron transfer. A half-reaction focuses on either the oxidation or reduction component of a redox reaction, detailing the movement of electrons and the species involved. This clarity is essential for understanding how changes in oxidation states occur as electrons are transferred between reactants.

Reduction potentials are measured under standard conditions, and presenting half-reactions allows chemists to easily compare the tendencies of various species to gain or lose electrons. This comparison helps in predicting the direction of redox reactions and determining which substances are more favorable as oxidizing or reducing agents.

When examining half-reactions, one can also more readily identify the stoichiometry of the electron transfer process involved, making it easier to calculate cell potentials and analyze electrochemical behavior. The focus on electron transfer through half-reactions is fundamental to the study of electrochemistry, aiding in both qualitative and quantitative assessments of redox reactions.