Lecture 12/3/14

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Lecture 12/3/14
2014-12-06 00:45:39
BME 221

BME 221
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  1. Name an application of electrolysis involving water, describe it, and identify all reactions involved.
    • Electrolysis of Water
    • Since H2 and O2 spontaneously form water, you need to supply energy to generate H2 and O2 from water.
    • The reactions happen at the electrodes are:(−)H+ + e− →12H2;(+)H2O →12O2 + 2 H+ + 2e−.
  2. Example: copper purification
    The impurities are generally more inert metals in the copper ore, such as gold and platinum

  3. Why use Pl as metal in an electrolysis reaction?
    Pl donates electrons but does not react
  4. Ex. Q:Do you think you can make a working battery if you have the following things available: a silver wire, a solution of AgNO3 of unit activity, a solution of zinc sulfate with unit activity, and a zinc electrode (you also have a salt bridge and everything else you will need)? What is the standard electrical potential? What would be the overall reaction of this battery? Which will be the cathode and which will be the anode?
    • Yes! You can make a Galvanic cell like this:(−)Zn(s)|ZnSO4(aq, 1M)||AgNO3(aq, 1M)|Ag(s)(+).
    • 0.800 − (−0.762) = 1.562 V.
    • 2 Ag+ + Zn → 2 Ag + Zn2+.
    • Ag will be the cathode and Zn will be the anode.