Chapter 3C - Primary Galvanic Cells

• study of chemical processes that cause electrons to move

• generated by movement of electrons from one element to another in a redox reaction

• aka voltaic cell • electrochemical cell that converts chemical energy into electrical energy from spontaneous redox reactions taking place within the cell

• a galvanic cell (or series) that contains the reactants needed to produce electricity • variety of shapes, sizes & voltage

Cannot be recharged

Can be recharged using a power supply & process of electrolysis

• reactants seperated in two half-cells • connected with wire & salt bridge • completes circuit & allows movement of electrons

• each cell contains conjugate redox pair • one half-cell is the site of oxidation, the other the site of reduction

• one electode in each half cell • must be solid & conduct electricity

• negative polarity • site of oxidation

• positive polarity • site of reduction

• the metal will be used as the electrode

• an inert (unreactive) electrode e.g. platinum or graphite

• a gas electrode containing platinum

• solution containing free moving ions

• joins two electrodes • allows flow of electrons from anode to cathode

• connects two electrolytes • completes the circuit • provides ions to compensate for those lost or gained during redox reaction in each half-cell

Potassium Nitrate (KNO₃) * both ions are spectators and will not interfere with the reactions in each half cell

• anions flow to the anode • cations flow to the cathode

• records the voltage (potential difference) produced by the cell

• electrodes & wire • where electrons flow

• salt bridge & electrolytes (movement of ions occurs)

• indicates difference in energy b/w two half-cells in a galvanic cell • measured in volts