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Homework Help: Density ?

  1. Feb 24, 2008 #1
    how would i start this solution off?

    we replace 7.5 atomic % of the chromium atoms in its BCC crystal with tantalum. X ray diffraction shows that the lattice parameter is 0.29158 nm find the density.
  2. jcsd
  3. Feb 24, 2008 #2


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    Well the crystal is bcc, and one is given the length of the side of the cube.

    Density is simply mass divided by volume.

    The mass is simply the number of atoms in the cell times the mass per unit atom (think amu, which can be converted into grams.). Also, since 7.5% of the Cr atoms are replaced with Ta atoms, simply adjust the atomic mass by the proportions of each element.
  4. Feb 24, 2008 #3
    thank you im going to try and work it out now the 7.5% Ta was confusing me but i think i get it now
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