In this chapter, we began by distinguishing between electrolytic cells and galvanic cells. In a galvanic cell, chemical energy is converted to electrical energy and the voltage or the emf of the cell is given by rG = - nF. The negative sign signifies that a degrease in the free energy of the chemical (cell) system and this corresponds to positive emf available to do work on the surroundings.
The cell representation and the convention used in writing the electrode on the right side, where reduction is occurring in the electrode written on the right hand side was outlined. The standard (reduction) potentials were arranged in an “electrochemical” series, using which the cell potentials of any cell can be easily calculated. The Nernst equation enables one to calculate the emf of a cell for any given activities (concentrations) of ions in solution.
The last section dealt with calculating rS and rH for reactions, if in addition to E (which gives rG), the temperature dependence of E, dE /dT can be measured experimentally. This option provides a very accurate method for determining rG, rH and rS for “electrochemical” reactions.
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. The negative sign signifies that a degrease in the free energy of the chemical (cell) system and this corresponds to positive emf available to do work on the surroundings. 
