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Homework Help: Beginner's Mass Ratio Problem

  1. Jan 22, 2009 #1
    1. The problem statement, all variables and given/known data

    What is the ratio of mass of a 12C atom to a 13C atom

    3. The attempt at a solution

    12.011/13 = .9239230769

    Solution given at back of book = .92286
     
  2. jcsd
  3. Jan 23, 2009 #2

    Borek

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    Staff: Mentor

    Why 12.011? Why 13?
     
  4. Jan 23, 2009 #3
    The atomic weight of C-12 is 12.011, the atomic weight of C-13 is 13. I divided the weight of C-12 by the weight of the C-13 to get a ratio.
     
  5. Jan 23, 2009 #4

    Borek

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    Staff: Mentor

    12.011 is not an atomic weight of C-12, just like 35.45 is not a mass of Cl atom.
     
  6. Jan 24, 2009 #5
    Ok, I understand that the atomic weight's are weighted averages. I just used the atomic weight because it asks for a ratio between two atoms. As for how to set it up I don't have the slightest idea how to set it up, no example problems to model form, nor solution steps.
     
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