How many molecules are 100.00 grams of H2O?

Answer 1

How many moles do you have?
100g/molar mass H2O = ?? moles.
There are 6.022E23 molecules in 1 mole of anything. And you have ?? moles.

Answer 2

200

Answer 3

100.00g H2O*(1mol H2O/18.02g H2O)*(6.022*10^23 molecules H2O/1 mol H2O)=3.3418423*10^24 molecules H2O or ~3.3418*(10^24) H2O molecules.