Question

Calculate the number of H2O molecules in a human body of mass 66.5 kg. Assume that, on average, water makes up 62% of the mass of a human body. (Use 1.0 u for the atomic mass of hydrogen, and 16.0 u for the atomic mass of oxygen.)
1

Answer 1

mass body = 66.5 kg = 66,500 g.
mass H2O = 66,500 x 0.62 = ?
mols H2O = ?g/18 = ?
Then remember 1 mol contains 6.02E23 molecules.

Answer 2

42molécules