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Gen Chem Question

Discussion in 'DAT Discussions' started by DrRoyal Pains, Jul 22, 2011.

  1. DrRoyal Pains

    7+ Year Member

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    PbO2 → PbSO4 : lead goes from +4 → +2 therefore PbO2 is reduced and is the cathode (choice A is correct)
    Pb → PbSO4 : lead goes from zero → +2 therefore Pb(s) is oxidized and is the anode

    For the first reaction I understand how lead is +4, but I do not understand how it is +2 in product. I know oxygen will be -8, but for some reason I am stumped on the Pb and S in PbSO4. What am I missing?
     
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  2. LetsGo2DSchool

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    You can approach it in two ways. The easier way is to look at SO4 as one entity which is equal to -2. Thus Pb has to be +2.

    The other way is more difficult: O4 is -8 so then S must be ? which makes Pb equal ?

    Whenever you see NO3, SO4, PO4, etc, do it the easier way.
     
  3. OP
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    DrRoyal Pains

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    I thought that was how you approached it. Thanks brah.
     
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