Redox reactions can be in solutions {cell, redox reaction}|. Conducting plates can be in two connected half-cells. Current from one electrode goes through wire to other electrode and then through solution.
potential
Metal and metal ion have potential difference, because electrons and ions separate. If potential > 0, metal favors reduction. If potential < 0, metal favors metal oxidation.
Nernst equation
If electrode voltage is > 0, reaction is spontaneous. At equilibrium, voltage = 0 and current = 0.
tables
Tables can show reduction-half-reaction potentials. Hydrogen electrode has standard potential 0 V.
diffusion
In fast reactions, diffusion controls reaction rate. Moving electrode or stirring solution minimizes diffusion effects.
salt bridge
Agar and potassium-chloride salt bridge can connect half-cells.
membrane
Membranes that block and allow ion flows can have potential difference, because membrane sides have different ion concentrations. Membrane-permeable ion diffuses through until electrostatic repulsion from higher-concentration side stops ion flow.
Physical Sciences>Chemistry>Inorganic>Oxidation-Reduction>Cell
5-Chemistry-Inorganic-Oxidation-Reduction-Cell
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Date Modified: 2022.0224