GALVANIC CELL

"An electrochemical cell that converts chemical energy into electrical energy. A cell in which chemical reactions occur spontaneously at the electrodes when they are connected through an external circuit, producing an electrical current. E.g., in a fuel cell hydrogen is oxidized at the anode by transferring electrons to the anode and the oxygen is reduced at the cathode by accepting electrons from the cathode. During this process the electrons are carried from the anode to the cathode through an outside electrical circuit where the electrical current can drive a motor, light a light bulb, etc. In contrast, in an electrolytic cell electrical power must be supplied to force the non-spontaneous reverse reaction, the electrolysis of water. See also electrochemical reaction, battery, and fuel cell. Also called ""voltaic"" cell. The free energy change of the overall cell reaction is negative. "