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Homework Help: Finding moles in a mixture

  1. Feb 18, 2008 #1
    General question:

    If given the mass (15.0 g) of a mixture of two solids (NaCl + C12H22O11), can I find the amount of moles in the mixture by multiplying (15.0 g)*(mol / mass NaCl + mass C12H22O11)? I don't think this is valid, but I don't know why not.....
     
  2. jcsd
  3. Feb 18, 2008 #2
    i dont think you can really do that... mainly because you dont know what fraction of the mixture is NaCl or C12H22O11.
     
  4. Feb 19, 2008 #3
    Well what if you're just trying to find the moles of solution present? Then would it matter the fraction of each?
     
  5. Feb 19, 2008 #4
    well.. that is sort of impossible to say the total moles of "solution present". for example, try making up your own values for a solution... like 20% A (molar mass 20) and 80% B (molar mass 5). you could then find find moles A and moles B and add them up together to find total moles.
    now try doing it again except with like 50% A and 50% B. You should get a different number of moles.. at least i hope so lol
     
  6. Feb 19, 2008 #5

    mgb_phys

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    Suppose I told you there was 1000tons of vehicles in the car park and they were a mixture of 0.5t Smart Cars and 10t Buses - you couldn't work out how many vehicles were present.
     
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