How many molecules of H2O in 100kg of snow?? dont know where the density comes in!! 1. The problem statement, all variables and given/known data How many molecules of H2O are there in 100kg of snow? Density of snow is given as 800 kg/m3 2. Relevant equations 1 mole = 6.023x10^23 molecules mass/molecular mass = number of moles 3. The attempt at a solution This is my attempt, ignoring the density. 1 mole of H2O = 6.023x10^23 molecules of H2O Hence 18g H2O contains 6x10^23 molecules 1g = 3.346x10^22 molecules 100,000g (100kg) = 3.346x10^27 molecules of H2O Where/how does the density come into it???