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Homework Help: Atomic mass number question

  1. Nov 8, 2006 #1
    sorry, i'm having trouble grasping a lot of this... i feel like i have a general understanding of what's going on but a lot of the problems are still confusing to me...

    this problem

    An element in its solid phase has mass density 1750 kg/m3 and number density 4.39 * 10^28 atoms/m3.

    asks what is the element's atomic mass number

    i thought that it should just be 4.39*10^28 divided by 1.661 *10^-27 = u, but then i'm not sure where the mass in kg comes in to play
  2. jcsd
  3. Nov 8, 2006 #2
    1 au = 1.661 *10^-27 Kg.
  4. Nov 8, 2006 #3
    yeah, i know the atomic unit number but how does it relate to mass density?
  5. Nov 8, 2006 #4
    can anyone point me in the right direction? i'm still not getting this :bugeye:
  6. Nov 8, 2006 #5


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    where rho is the mass density, n is the number density and m is the mass of the atoms.
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