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Ch.2 - Atoms, Molecules & Ions

Chapter 2, Problem 8

Which sample has the greatest mass? (LO 2.16) (a) 5.5 mol of C (b) 2.1 mol of S (c) 4.2 mol of Be (d) 0.52 mol of Ag

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Hi everyone. This problem reads identify which of the following has the largest mass. Okay. Were given for option choices here and they're all given in moles and we know that mass is in grams. So we need to go from moles to go grams for each of these and determine which one has the largest mass. So we're going to need to convert each of these from moles to grams and we'll do this using the periodic table. Okay? So for a we're going to start off with what we're given, which is 0.28 moles of lead. We want to go from moles of lead. two g of lead. The way that we'll do this is by using the molar mass of lead. So for every one mole of lead, The mass is 207.2 g of lead. And that's found on the periodic table. So our moles cancel and we're left with unit of g. Okay? So once we take .28 and multiply it by 207.2 we get an answer of 58.02 g of lead. Okay, so that's the mass for a for B we know we have 6.2 moles of oxygen. We want to go from moles of oxygen. two g of oxygen. And we'll do that using the molar mass of oxygen In one mole of oxygen, there is 16 g of oxygen. Okay, so our moles cancel and we're left with g. Our mass of oxygen is 99.2 g. Okay, For c we have 1.8 moles of sodium. We want to convert this from moles of sodium two g of sodium and we'll do that using the molar mass and one mole of sodium there is 22.99 g of sodium. So 1.8 times well our units cancel and we have 1.8 times 22. is equal to 41.382 g of sodium. And lastly we have D which is 3.6 moles of bro. Me. Okay, so we want to go from moles of grooming, two g of grooming And one mole of grooming. There is 79.90 g of grooming Our units of moles cancel and we're left in g and we have a mass of 287.64 g of bro. Mean, so let's go ahead and write out what each is. This is bro, I mean this is sodium, this is oxygen and this is lead. So the question asked for which has the largest mass and as we can see here, our largest mass is 287.64 g of bro. Mean? So that makes answer choice. D. The correct answer. 3.6 moles of bromine is going to have the largest mass out of the following choices given. Okay, so that is it for this problem. I hope this was helpful
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