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Homework Help: Oxidation reaction-which is oxidized?

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  1. Oct 21, 2017 #1
    1. The problem statement, all variables and given/known data

    2Ag2S(s) + O2(g) = Ag2O(s) + S(s)

    Which is being oxidized?

    2. Relevant equations
    N/a

    3. The attempt at a solution

    Reactants:
    Ag2S is neutral, with Ag having +1 charge and S having 2- charge.
    O2 is neutral

    Products:
    Ag2O is neutral, with Ag having a 1+ charge and O having -2 charge.
    S is neutral.


    So: Reactants and products have the same net charge?

    But, S when from 2- to 0 charge. Therefore, it was oxidized (gained two electrons).
    Oxygen went form 0 to 2-. So, it was reduced.
    Ag stayed the same. 1+ to 1+.

    But, I read that Ag is actually being oxidized.
    I'm not really sure what's happening.
     
  2. jcsd
  3. Oct 21, 2017 #2

    Merlin3189

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    Homework Helper
    Gold Member

    I agree with your analysis.
    Oxidation and reduction are two sides of the same coin, which is why these reactions are often called redox reactions.

    When Ag + 2S -> Ag2S the silver is oxidised from Ag to Ag+ and the sulphur reduced from S to S2-
    The silver was already oxidised and did not change. The S2- was oxidised back to S
     
  4. Oct 21, 2017 #3

    Borek

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    Staff: Mentor

    Bullseye.
     
  5. Oct 21, 2017 #4

    Merlin3189

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    Gold Member

    So much more concise than me!
     
  6. Oct 21, 2017 #5
    Thank you for your help; both of you! I'm relieved that I am thinking about this the right way!
     
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