# Anyone Up Late? Need Help With Chemistry :)

Discussion in 'After Hours Lounge (Off Topic)' started by Henry Carmona, Feb 12, 2004.

1. ### Henry Carmona Screenwriter

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How do i figure this:

Calculate the number of oxygen atoms in 29.34 grams of sodium sulfate, Na2SO4?

I hate chemistry

Anyway, Na=22.99 S=32.07 & O=16.00

I know that if it was just asking how many atoms in 1 mole i could just multiply Oxygen by 4 correct?

That is, (4)(avagadros number) = # of O atoms.

Thanks!

2. ### Wayne Bundrick Cinematographer

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It's been 17 years but I'll try.

1 mole of Na2SO4 is
(2 * 22.99) + (32.07) + (4 * 16.00) = 142.05 grams per mole

So 29.34 grams of it is 29.34/142.05 = 0.2065 mole of Na2SO4

4 Oxygen atoms per Na2SO4 molecule * 0.2065 mole of Na2SO4 = 0.8262 mole of Oxygen atoms

"Avocado's number" is 6.02e23 atoms per mole
6.02e23 atoms per mole * 0.8262 mole = 4.97e23 atoms

Somebody check my work please.

3. ### Scott_J Cinematographer

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Checking Wayne's work, the numbers are correct and the method seems to be right as well (although it's been a few years since I took Chem).

4. ### Scott_MacD Supporting Actor

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Correctamundo, Wayne.

It's been a while for me too.

5. ### Mark Fitzsimmons Supporting Actor

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Do you know the factor label method? Its the easiest way to do these types of problems.

BTW, this is high school chemistry right?

6. ### Wayne Bundrick Cinematographer

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For me, it was first year high school chemistry, right about this time of the year in fact.

When I said it's been 17 years that got me thinking. I've reached the age where I've been out of school longer than I was in school, not counting college. I've reached the Middle Ages!

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