And then we multiply that by our avocado's number remembering that 1 mol of anything is this many atoms or molecules in our case. Now, let's take our amount in grams of water and divide it by our molecular weight of water which we can find on the periodic table which is 18 grams/mol. The way we found that is we simply added up the atomic weight of oxygen plus two atomic weights of H because we have two H atoms. So 16 for oxygen and two times one for H two gives us 18 grams/mol for a single water molecule. So 20 grams of water divided by 18 grams/mol we see that the grams cancel, the moles go on top and we get one point moles of water. So this means within our 20 grams of water there are one point eleven moles of water.