Although the problem was worked using carbon (the element upon which Avogadro’s number is based), you can use the same method to solve for the mass of any atom or molecule. If you’re finding the mass of an atom of a different element, just use that element’s atomic mass. If you want to use the relation to solve for the mass of a single molecule, there’s an extra step. You need to add up the masses of all of the atoms in that one molecule and use them instead. Let’s say, for example, you want to know the mass of a single atom of water. From the formula (H2O), you know there are two hydrogen atoms and one oxygen atom. You use the periodic table to look up the mass of each atom (H is 1.01 and O is 16.00). Forming a water molecule gives you a mass of:1.01 + 1.01 + 16.00 = 18.02 grams per mole of water and you solve with: mass of 1 molecule = mass of one mole of molecules / 6.022 x 1023 mass of 1 water molecule = 18.02 grams per mole / 6.022 x 1023 molecules per mole mass of 1 water molecule = 2.992 x 10-23 grams