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Chemical transformation (Decomposition)

  1. Feb 1, 2014 #1
    Hi, I was wondering when you need to write the decomposition of a substance, how do you know if the number is going to be a coefficient or subscript ?


    2H2O ===>2H2 + 02 would be the answer

    But why not

    2H2O ==> 2H2 + 2O

    Knowing that we have 2 moles of O in the beginning...

    So ?

    Thank you!
  2. jcsd
  3. Feb 1, 2014 #2
    Although 2H2O ==> 2H2 + 2O does not violate Lavoisier's law, oxigen is a diatomic molecule and therefore the substance 'O' that appears in that equation doesn't truly exist.
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