# Chemistry Unit conversion question

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

1. ### crazyengineer Thread Starter Member

Dec 29, 2010
156
2
Hello,

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?

Jul 7, 2009
1,585
141
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
156
2
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.