I have the mass of the amount of substance, and the molar masses. How do I do this? Is this the same as calculating the number of molecules/ formula units? Also, I know the number of atoms for each element in the compound (It made me calculate that before)

Answer 1

You don't have all of the information for me to answer. Why not type specific question and tell us what you don't understand about it.\
mols = grams/molar mass
# molecules = mols x 6.02E23
# atoms = #molecules x (#atoms/molecule)