Calculate the percentage of empty space in 1 mol of water at 25C. Obtain the density from the experiment " Some Measurements of Mass and Volume." The volume of a molecule of water can be taken as the sum of the volumes of the two hydrogen atoms and the oxygen atom. Use the single-bond covalent radii of 37 pm for hydrogen and 66 pm for oxygen and V=4pi^3/3 to calculate the volume of each atom.