what's the atomic weight of water
Water (H2O) is made from 2 atoms of hydrogen and 1 atom of oxygen. A mole of water molecules would be 2 moles of hydrogen atoms plus 1 mole of oxygen atoms. From the periodic table we see the atomic weight of hydrogen is 1.0079 and the atomic weight of oxygen is 15.9994. Atomic mass is the number of grams per mole of the element. This means 1 mole of hydrogen weighs 1.0079 grams and 1 mole of oxygen weighs 15.9994 grams. Water would weigh. weight of water = 2(1.0079) g + 15.9994 g. weight of water = 2.0158 g + 15.9994 g. weight of water = 18.0152 g.