00:02
Hi there, in this question we are given the heat of vaporization, so hvap, and it is, it tells us that it is 40 .7 kj of energy are needed to vaporize every mole of h2o.
00:26
Okay, so we want to know the total amount of energy that's going to be required to vaporize a 45 .0 ml sample at its boiling point.
00:39
So we have 45 .0 ml of water, and we need to get that to moles so that we can use our equality here for the heat of vaporization.
00:56
Alright, well the first thing, i do have a density here, and it's in grams per ml, so that's the first thing i want to use.
01:04
It tells me that there's 1 .00 g of h2o in every ml.
01:11
I put ml in the denominator so that would cancel.
01:13
Alright, now we can convert to moles because we know the molar mass of h2o, or we can calculate it anyway...