 Okay, let's do one of these density problems. Another density problem, it says an empty graduated cylinder weighs 45.8772 grams. After adding 20.0 mls of a liquid, the cylinder and its contents now weigh 77.7572 grams. What is the density of the liquid in grams per mil? So the first thing you're going to have to do, so well, if you want to remember, right, density equals mass divided by volume, like that, okay? So we have the volume of the liquid, but we don't have the mass of the liquid, right? So we're looking for the density of the liquid. So how do we get the mass of the liquid? We take the filled mass, subtract it from the empty mass, okay? So the mass of the liquid is going to be the mass of the filled cylinder minus the mass of the empty cylinder. Does that make sense? Because what's in it is the liquid, right? So all we've got to do is take 77.7572 grams, subtract 45.8772 grams from it. It depends on running out of ink, of course. 77.7572.8772. And I get 31.8800 grams, because we have to do four after the decimal, okay? So that's going to be the mass of the liquid, right? So the density of the liquid is going to be the mass of the liquid divided by the volume of the liquid. And so we've got the mass of the liquid, the volume of the liquid. We should be able to figure out the density, okay? So mass 31.8800 grams, volume 20.0 mils. And I think this says it wants it in grams per mil. So divide that by 20. And that's going to be the three sig figs. So 1.59 grams per mil is the density of this liquid. Okay, questions on that one? No, I was reading something totally different. Okay, well that's the way to do it, okay? No. Don't listen to anything. No, on the net, on the paper. Oh, okay, yeah.