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Calculating Avagodro's Number

  1. Feb 2, 2009 #1
    1. The problem statement, all variables and given/known data

    The element Ru has hcp packing with a hexagonal unit cell. The density of Ru is 12410 kg/m^3 and the cell volume is 2.711 x 10-23 mL. Calculate the value of Avogadro's number to three significant figures based on these data. (Note: the value may differ from the tabular value).

    2. Relevant equations

    D= 12410 kg/m^3 , V= 2.711 x 10-23 mL

    3. The attempt at a solution

    6 atoms (m^3/12410 kg)(1/2.711e-23 mL)(1000 mL/1 L)(1 L/0.001 m^3)(1 kg/1000g)(101.07 g/1 mol)

    I end up with 1.80e24 which is 3x the true value...this method works for every other structure but the hcp
     
  2. jcsd
  3. Feb 3, 2009 #2

    Borek

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    Staff: Mentor

    Are you sure it is six atoms per unit cell?
     
  4. Feb 3, 2009 #3
    I was told that for the base its 2 for simple its 1 and for face its 4, but hcp no one told me except for a tutor and he said it was 6. Is it wrong?
     
  5. Feb 3, 2009 #4

    Borek

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    Staff: Mentor

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