The first step is to find the moles of water. The second step is to find the moles of ethylene glycol. And the third step is to use the formula to find vapor pressure. Now, in the first step, before we find the moles, we first have to find the amount in grams of water. To find the amount of grams of water, we must first look up the density of water. The density of water is 1 gram per ML.