Fundamentals E.9

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Denise Montes 3B
Posts: 15
Joined: Thu Jul 25, 2019 12:17 am

Fundamentals E.9

Postby Denise Montes 3B » Sat Oct 05, 2019 6:37 pm

For E9 B how do you find the number of formula units present, how do I convert my answer from part A to get part B?

Jessica Tejero 3L
Posts: 54
Joined: Wed Sep 25, 2019 12:16 am

Re: Fundamentals E.9

Postby Jessica Tejero 3L » Sat Oct 05, 2019 6:44 pm

To find the formula units of the compound I believe you take the amount of sample and divide it by its molar mass in order to get the moles of the sample. To find the formula unit from the compound use Avogadro's constant
= (5.15g/(246.48 g/mol))(6.022x10^23)

Leyna Dang 2H
Posts: 104
Joined: Thu Jul 25, 2019 12:17 am

Re: Fundamentals E.9

Postby Leyna Dang 2H » Sat Oct 05, 2019 10:21 pm

For B, you don't need to use your answer from A in order to find your formula units! In order to get your formula units when you're given the grams of a sample, you'd have divide it by the molar mass of the sample (in this case, it is 246.46 g/mol which you get this by adding up the mass of each element). Because grams are now canceled out, you're left with the mols of the sample, but the question is asking for formula units. You'd have to multiply using Avogadro's number, 6.022*10^23 formula units/ 1 mol, in order to cancel out the mols and get your final answer.

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