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One more battery question

  1. Apr 20, 2015 #1
    In a standard galvanic half-cell when Zinc rode is placed into the Zinc sulphate. What is the reaction which makes zinc to dissolve and fell into the solution. Why do electrons move away from the sides of the electrode? Are they repelled by the solution or by other ZN atoms on the electrode which haven't been ionized yet?
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  3. Apr 20, 2015 #2

    Simon Bridge

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    Last edited: Apr 20, 2015
  4. Apr 20, 2015 #3
    From the link which you posted it is said that: In this cell the zinc metal has a tendency to dissolve as ions leaving its electrons on the electrode.

    I cant get the order: whether it is Reaction with the solution which causes electrons to fly away from Zn metal, or it is the attraction from the positive electrode which attracts loosely bound Zn electrons and as soon as Zinc start lacking electrons it will become Zn2+ and mix with the solution. If it is the latter case then when the electrodes are not connected will there be an excess of electrons on the negative terminal of the battery

    This is what is unclear for me. I understand how the redox reaction works but I cant understand how the half-redox reaction works.

    Thank you for your response.
  5. Apr 20, 2015 #4
    The electrodes themselves must be electrically neutral and thus there will be no voltage? Am I right?
  6. Apr 20, 2015 #5

    Simon Bridge

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    The electrodes don't have to be electrically neutral, and generally won't be - the webpage gives example reaction relations.
    So how do you understand redox reactions working?
  7. Apr 20, 2015 #6
    In redox reaction one atom loses electrons and another atom gains electrons.
    Is it possible for a redox reaction to occur just by simply placing atoms of zinc and copper together or we need to have an oxidizing/reducing agents for this to happen?
  8. Apr 20, 2015 #7
    My question is. Will the following reaction happen if there was no solution.
    Zn(s) + Cu2+(aq) doublearrow.gif Zn2+(aq) + Cu(s)
    I suspect there should be some energy given off which will make electrons pop from the Zn nucleus. Is the attraction between the positively charged Copper ion and Zn atom is enough to make them move??
  9. Apr 21, 2015 #8
    From Wikipedia:
    metallic zinc at the surface of the zinc electrode is dissolving into the solution
    Can you explain what makes them dissolve into the solution? The solution is just a mix of Zn2+ and SO42-. Do Zn atoms react with Zn2+ or S042- ?
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