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Homework Help: Standard change of enthalpy, hess's law question

  1. Oct 10, 2012 #1
    1. The problem statement, all variables and given/known data


    2. Relevant equations

    in pic

    3. The attempt at a solution

    So I multiplied the H2 + 1/2O2 equation by 3 and added it to the (N2H4, 2NH3) equation.

    I got H2O to match up and O2 to match up, but I don't know how to manipulate the other

    equations to get 4N2 to match up. Do I divide all by four? I don't know.
    Please help.
  2. jcsd
  3. Oct 11, 2012 #2
    please copy and paste the question -- do not link it; I have no way of knowing whether it is a scam link.
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