What is the mass of a 0.650 mol sample of vitamin C? And we're given the formula of vitamin C because we're going to need to find that molar mass. Anytime we're dealing with going between the mass of a substance and mols of a substance, we're going to use the molar mass. So that's like first thing I'm going to do here for this problem. And so I see I have carbon, hydrogen, and oxygen. There are 6 carbons, each with a mass of 12.000 grams per mol. I have 8 hydrogens, each with a mass of 1.008 grams per mol. And 6 oxygens each with a mass of 16.00 grams per mol. And what I'm going to do is add those values up in order to get the mass, the molar mass of vitamin C. And when I do that, I get a mass of 176.06 grams per mol. But note, I'm not done there because this is not a mass, this is a molar mass. It tells me how many grams I have per mol of C6H8O6. Now, I need to use that along with the mols of sample I was given in the problem to find the mass of that particular sample. And so when I look at the numbers about trying to decide where to start I notice that this number only has one unit associated with it. And so that's typically where I'm going to start the problem. So I have 0.650 mols of C6H8O6. Now I need to use the molar mass in such a way that the moles will cancel out with one another. And to do that I'm going to have to have mols on the bottom of this next step, so I get 176.06 grams per mol of C6H8O6. Now I see that mols of the vitamin C cancel with mols of vitamin C, and the units I'm left with are grams of vitamin C. So now I can simply do the math, and multiply 0.650 times the 176.06, and what I end up with is 114 grams of C6H806, and this is reasonable. I notice that I have a little more than half a mol of my compound, and what I have is a little more than half the mass of a single mol of the compound.