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Chemistry Unit conversion question

Discussion in 'Physics' started by crazyengineer, Aug 31, 2011.

  1. crazyengineer

    Thread Starter Member

    Dec 29, 2010

    I just have a quick question about unit conversion. Let say I have 144.6g/mol of GaAs and I divided it by 69.7g of Ga. Does that mean that I get a 2.07 As since the Ga from the compound and Ga from the single element cancels and the masses also cancels?
  2. someonesdad

    Senior Member

    Jul 7, 2009
    No. By 144.6 g/mol, I assume you mean the molecular mass of GaAs; this is the mass of a specified number of atoms (one Avogadro's number of atoms -- if you were to divide 144.6 g by Avogadro's number, then you'd have the mass in g of one GaAs molecule). You also can't "cancel" elements like you intimated -- that's undefined.

    If you divide 144.6 g/mol by 69.7 g, you get a number with the units 1/mol.

    Why don't you state what it is you're after? Then we can help you get what you want.
  3. crazyengineer

    Thread Starter Member

    Dec 29, 2010
    I'm trying to find the Ga atoms/cm^3. The only given is the lattice constant of GaAas (5.43 Angstoms), the molar mass of Ga and the molar mass of As.

    I also tried doing this way

    I divided the molar mass of Ga by the molar mass of GaAs then multiplied the atoms/cm^3 of GaAs.