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Homework Help: Need help with isotopes: Chemistry!

  1. Jan 15, 2007 #1
    1. The problem statement, all variables and given/known data

    Sulfur has 4 naturally occurring isotopes:

    Sulfur-32 Abundance = 95.0%
    Sulfur-33 Abundance = 0.76%
    Sulfur-34 Abundance = 4.22%
    Sulfur-36 Abundance = 0.014%

    Sulfur's symbol is S, it has 16 electrons and a mass of 32.06g

    2. Relevant equations
    I'm actually looking for the actual formula which I lost.

    3. The attempt at a solution
    Sulfur's Isotopes divided by its abundance...
  2. jcsd
  3. Jan 15, 2007 #2


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    Staff Emeritus
    Science Advisor

    What's the actual question here? What formula are you looking for?
    Last edited: Jan 15, 2007
  4. Jan 15, 2007 #3
    how do i find calculate the average atomic mass for sulfur?
  5. Jan 16, 2007 #4


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    Staff Emeritus
    Science Advisor

    Well, would you not take the sum of (mass of isotope*abundance of isotope) then divide the sum by 100?
  6. Jan 16, 2007 #5
    m = mass of specified isotope
    a = abundance of specified isotope as a part of 1.00 (100%

    (m-32 x a-32) + (m-33 x a-33)... etc.

    so (32.06 x .95) for sulfur-32 and so on
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