Labels:text | screenshot | font | diagram | line | number OCR: Formula Mass in grams is found with the help of the periodic table. H20 Water consists of 2 atoms of Hydrogen and 1 atom 1 of Oxygen. From the periodic table we see. H - Hydrogen has a mass of approx. 1.0 units 1.008 - Oxygen has a mass of approx. 16.0 units Water consists of 2 Hydrogen atoms, each having 8 a mass of one unit, plus one Oxygen atom having 0 a mass of 16 units. 1.0 + 1.0 + 16.0 = 18.0 units 15.999 for water's formula mass. Water's formula mass = 18.0 units One mole of water = 18.0 grams