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Homework Help: Volume, moles, density, molar mass =>separation of molecules!

  1. Aug 18, 2009 #1
    1. The problem statement, all variables and given/known data
    I am doing an exercise from my physics book right now.
    I am given:

    1 molecule of hydrogen corresponds to 3.7x10^-26 m^3
    1 molecule of led corresponds to 2.99x10^-29 m^3

    the ratio of these volumes is 1.22x10^3

    Q: Determine that the order of magnitude of the ratio separation of hydrogen molecules / separation of lead atoms is 10

    2. Relevant equations

    3. The attempt at a solution
    I have calculated the given data i described above, this is part d of the question and i have no idea!
  2. jcsd
  3. Aug 18, 2009 #2
    you are talking about molecules and not atoms. Therefore, as an example hydrogen normally comes in pair, meaning "H2". If you say that this molecule is 3.7 x 10^-26 m^3, than you can find the distance that seperate them, by know the size of the hydrogen atom. You do the same for the lead molecule and make a ration.

  4. Aug 18, 2009 #3
    the question is exactly the one i stated in my first post. hydrogen molecules and led atoms.
    any ideas ?
  5. Aug 19, 2009 #4
    Ok, you ddi not get my last post. To find the average distance between the two atoms in a molecule, you need to substract the size of the molecule by the size of the atoms. Once you have the two, make a simple ratio.

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