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Homework Help: Mole concept

  1. Feb 8, 2016 #1
    1. The problem statement, all variables and given/known data
    When a problem says 76 moles of P4O10 contains how many moles of P.
    I can't seem to see why 76 moles of this molecule would contain more moles in it.

    2. Relevant equations

    3. The attempt at a solution
    I know the answer is 76 moles of P = 76 * 4
    but how could a compound P4O10 that has 76 moles have 76 moles of P and 76 moles of O. in my head thats like saying 25 lb back of wine bottles is 25 lb of wine + 25 lb of bottles. Can anyone help me fix this brain dump?
  2. jcsd
  3. Feb 8, 2016 #2


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    Mole is a number, like say 10 or a dozen or 512. If you have a dozen molecules of P4O10, then there are four dozens of P and 10 dozens of O in it.
    Same with moles.
  4. Feb 8, 2016 #3


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    Staff Emeritus
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    There's a difference between the number of ##P_4 O_{10}## molecules and the number of ##P## atoms.
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