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Unformatted text preview: mical cell.
Electrochemical cells have both a magnitude for the measured voltage and a polarity. An
electrode that is positive, relatively speaking, must be deficient in electrons, and hence a
reduction must be taking place at that electrode. Conversely, an electrode that appears
negative has a surplus of electrons. Hence, electrons are being released into it by an 11 oxidative half-reaction. By definition, oxidation occurs at an anode. Hence, the (-) pole
of an electrochemical cell is necessarily its anode, and the (+) pole is its cathode (where
the reduction occurs).
The directions for this experiment exploit the fact that electrochemical cells can be
described very efficiently by using conventional "cell diagrams." A possible diagram for
a galvanic cell that employs the net ionic reaction,
2 Ag+(aq) + Cu(s) Cu2+(aq) + 2 Ag(s)
Cu(s) | Cu(NO3)2(aq) (0.1M) || AgNO3(aq) (0.1M) | Ag(s)
The corresponding measured conventional cell voltage is roughly +0.4 V.
The cell diagram contains the information necessary to construct the ele...
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- Spring '07