Electrochemistry is the study of reactions caused by electric current and reactions which are capable of generating electric current. It may also be viewed as the study of the interconversion of chemical and electrical energy. Electrochemistry involves oxidation-reduction reactions. These reactions involve the transfer of electrons and consequent changes in the oxidation states of atoms during chemical reactions. Oxidation-reduction (or redox) reactions occur without passage of electric current when they take place between reagents that were in direct contact: ions or molecules in solution, gases mixed in the vapor phase, or liquids contacting solids. In electrochemistry, however, the reagents undergoing oxidation and reduction are actually physically separated from one another and contained in the compartments of a device called a cell. The reagents that are coupled in these oxidation-reduction reactions use some conduit to transfer charge from one compartment to another--in many cases a wire, in others a...