Textbook Error: Short Circuiting an Electrochemical Cell
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Sometimes errors in electrochemistry discussions are not in the text but in the figures. Many errors in the electrochemical chapters of general chemistry textbooks have been reported previously, yet we found a serious error in the diagrams in eight, 21st century texts. The figures in them show many of the cells shorted out with a wire. Since a shorted electrochemical cell produces no measurable voltage it is unreasonable to ask students to calculate the voltage produced by such a cell. Depending upon the pedagogical context, these diagrams are either seriously wrong or reflect a poor choice of a load for the cell. We offer suggestions as to what loads might be appropriately shown in textbook diagrams within different electrochemical contexts. We also offer an analogy to electrical potential energy and include a diagram to clarify the interrelationships between electromotive force E, reaction quotient Q, and Gibbs free energy G (an EQG diagram).