To determine the empirical formula of magnesium oxide. Mass of crucible and lid (step 1) 50.00 Mass of crucible, lid and magnesium (step 3) 50.24 Mass of crucible, lid and magnesium oxide (step 7 ...

of~an~element} = \frac{mass~of~an~element~in~the~compound}{relative~formula~mass~M_r} \times 100\) There are six atoms of hydrogen in the compound, so the mass of hydrogen is 6 × 1 = 6.