Knowra Half-reaction Half-reaction A balanced equation showing the oxidation or reduction part of a redox reaction, with electrons written explicitly. Two half-reactions combine by canceling electrons to give the overall reaction.
Oxidation : Loss of electrons by an atom, ion, or molecule, increasing its oxidation state. An oxidation half-reaction places the electrons among its products.
Chemical equation : A symbolic representation of reactants and products in a chemical reaction. A half-reaction is one component of a full chemical equation.
Standard electrode potential : The voltage associated with a reduction half-reaction under standard-state conditions, measured relative to a reference electrode. Tabulated reduction potentials let half-reactions predict cell voltage and reaction direction.
Overall redox reaction : The complete equation for a redox process, with electrons canceled from its two half-reactions. Unlike an individual half-reaction, it shows the net chemical change without free electrons.
Reduction : Gain of electrons by an atom, ion, or molecule, decreasing its oxidation state. A reduction half-reaction places the electrons among its reactants.
Conservation of charge : The principle that total electric charge remains constant in a closed process. Explicit electrons make charge conservation checkable on both sides.
Nernst equation : An equation relating an electrochemical cell potential to concentrations, temperature, and standard potential. It adjusts half-reaction potentials when solution conditions depart from standard states.
Oxidizing agent : A reactant that accepts electrons and is thereby reduced. It appears on the reduction side, while the half-reaction names the electron-transfer change.
Oxidation state : A bookkeeping charge assigned to an atom under rules for assigning bonding electrons. Changes in oxidation state identify which species lose or gain electrons.
Stoichiometric coefficient : A number placed before a chemical formula to specify its relative amount in an equation. Coefficients balance atoms and match electron counts between the two halves.
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