Page 83 - Academic Press Encyclopedia of Physical Science and Technology 3rd Analytical Chemistry

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Encyclopedia of Physical Science and Technology EN005M-206 June 15, 2001 20:25

Electrochemistry

Donald T. Sawyer
Texas A&M University

I. Fundamentals
II. Electrode Potentials and Potentiometry
III. Controlled-Potential Electrolysis
and Voltammetry
IV. Electron-Transfer Processes
V. Electrochemical Characterization of Molecules
VI. Industrial Electrosynthesis
VII. Batteries and Fuel Cells
VIII. Corrosion; Cathodic Protection

GLOSSARY Electrode Conducting material (usually metal or carbon)
that is immersed in an electrolyte solution and is a
Anode Electrode at which a chemical oxidation occurs source or sink for electrons.
with removal of electrons; the negative terminal for Electrolysis Passage of ionic current through an elec-
spontaneous cell reactions (batteries, galvanic cells, trolyte solution with reduction of an electroactive
and fuel cells); the positive terminal for imposed cell species at the cathode and oxidation of an electroac-
reactions (electrolysis cells and voltammetric cells). tive species at the anode.
Cathode Electrode at which a chemical reduction occurs Electrolyte Solution that conducts ionic current via ionic
via introduction of electrons; the positive terminal for transport (ions of dissolved salts, mineral acids, or
spontaneous cell reactions (batteries, galvanic cells, strong bases).
and fuel cells); the negative terminal for imposed cell Indicator electrode Electrode that responds to the ac-
reactions (electrolysis cells and voltammetric cells). tivity (thermodynamic effective concentration) of a
Cell Container that includes the electrodes (anode and solution species in potentiometric and voltammetric
cathode)connectedviaanelectrolytesolution.Physical measurements.
contact between the anode and the cathode and mixing Reference electrode An electrochemical half-cell with
of electrolysis products from the two electrodes often a stable and known potential. The most common is
is prevented by the use of separators (membranes or the saturated calomel electrode (SCE, +0.242 V vs
inert materials). NHE). The primary standard reference electrode is
Electroactive species Molecules that are transformed at the normal hydrogen electrode (NHE, 0.0000 V by
the anode and cathode. definition).

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