how many atoms in h2o
Water consists of H2O molecules that each conprise 3 atoms. A typical H2O molecule as a molecular weight of 18, disregarding isotopes. That means one mole weighs 18 grams. 1000 g / 18 g = 55.6 mole H2O in a liter of water. One mole is around 6 x 10^23 so around 3 x 55.6 x 6 or 1000 mole atoms. Wolfram|Alpha confirms: how many atoms are in a liter of water.