 Okay, let's try this problem here. Calculate the number of moles and 3.0 grams of chlorine. So, moles, remember, and Cl2. So, 3.0 grams, and we need to figure out what the molecular weight of chlorine gas is. So guys, I'm going to form one chlorine atom, of course, that weighs 35.45 AMU. So, 2 chlorine atoms, you're going to weigh 2.7, right? So, 2 times that equals that. So, that's going to be 70.9 ohm Mu. And remember, you can approximate that to say that the molar mass of chlorine gas is going to be 70.90 grams per mole. So, now all you got to do is multiply it by the inverse or divide it by the molar mass. Cancel, and you get the number of moles. 3.0 divided by 70.9, 0.042 moles.