Question

If a sample of Mg3(PO4)2, has a mass of 0.600 g, what is the mass of phosphorus in that sample?

Answer 1

mols Mg3(PO4)2 = grams/molar mass
mols P atoms is 2x that.
mass P atoms = mols x atomic mass.

It can be done another way by find the percent P in Mg3(PO4)2.
%P = (2*atomic mass P)/(molar mass Mg3(PO4)2)*100 = ?
Then 0.600 x %P/100 = ?

Answer 2

.144