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Homework Help: Electrochemisty/Redox Reactions Help Needed

  1. Dec 4, 2006 #1
    1. The problem statement, all variables and given/known data

    2. Consider an electrochemical cell as shown, with Zn in ZnCl2(aq) and Cu in Cu(NO3)2(aq), and a salt bridge containing KNO3(aq). The overall chemical reaction is
    Zn(s) + Cu2+(aq)  Zn2+(aq) + Cu(s).

    a. How many moles of electrons are transferred in this reaction?
    b. Which side is the anode?.
    c. Which direction will electrons travel?
    d. Which material is being reduced?
    e. What is the oxidizing agent?

    2. Relevant equations

    a for a i understand that 2 moles of electrons are transferred throught the salt brige. From anode to cathode.for b i said that the left side is the anode and c) that the electrons travel from zinc to copper
    for d: o recognize that Cu 2+ is being reduced because it gains 2 electrons and becomes Cu (s). for e i think that since Cu 3+ is rduced it is the oxidizing agent..

    3. The attempt at a solution

    but my professor says the electrons flow from copper to zinc andthat zinc is the oxidizing agent...can anyone explain?
  2. jcsd
  3. Dec 4, 2006 #2
    Write the half reactions:

    [tex] Zn \rightarrow Zn^{2+} + 2e^{-} [/tex]

    [tex] Cu^{2+} + 2e^{-} \rightarrow Cu [/tex]

    The electrons flow from zinc to copper and copper is the oxidizing agent.
    Last edited: Dec 4, 2006
  4. Dec 4, 2006 #3


    User Avatar

    Staff: Mentor

    Google reactivity series.
  5. Dec 4, 2006 #4
    thanx so i guess my prof was wrong thanx
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