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Topic: How many H atoms are present in a 2.00 g sample of styrene?  (Read 7300 times)

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Offline alexs0fly

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How many H atoms are present in a 2.00 g sample of styrene?
« on: September 10, 2007, 08:07:01 PM »
"The emperical formula of styrene is CH. The molar mass of styrene is 104.14 g/mol. How many H atoms are present in a 2.00 g sample of styrene?"

I've already got the molecular formula - C8H8 but idk where to go from here. I know there are 6.02x10^23 particles of 1 mol of anything. And there are 8 moles of H right? Where does the 2.00g come into play?
« Last Edit: September 12, 2007, 03:44:59 AM by Mitch »

Offline Yggdrasil

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Re: Help
« Reply #1 on: September 10, 2007, 08:10:30 PM »
How many moles of styrene are in 2.00g?

Offline alexs0fly

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Re: Help
« Reply #2 on: September 10, 2007, 08:18:45 PM »
.0192

Offline Borek

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Re: Help
« Reply #3 on: September 11, 2007, 02:47:06 AM »
How many styrene molecules per 0.0192 mole of styrene?

How many hydrogen atoms per styrene molecule?

Note: where did you get the C8H8 formula from? It is correct, but it should be calculated from the data given in the question.
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Offline AWK

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Re: Help
« Reply #4 on: September 11, 2007, 03:18:39 AM »
Molecular mass and formula are not needed in your calculations.
Calculate mass fraction of H in your empirical formula (~1/13), then multiply it by a mass of your sample (~2/13) - this is the mass of hydrogen in your sample. Then convert it to moles of atoms, and finally to a number of hydrogen atoms
AWK

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