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posted by  tored ryan on 8/27/2008 5:59:30 PM  |  status: Live  

Need help!!!!! lifesaver's on!

Course Textbook Chapter Problem
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Question Details:
A sample of N2O4 contains 1.14 moles of nitrogen. Use the following atomic masses: N =14, O=16.
The number of moles of N2O4 present = mol N2O4
The mass of the sample = g N2O4
The number of moles of oxygen in the sample = mol O
The mass of oxygen in the sample = g O

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Sage
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posted by kwyjibo on 8/27/2008 6:38:45 PM  |  status: Live
Asker's Rating: Helpful   
tored ryan's comment:
"Thanks though!"
Response Details:
MW N2O4 = 2*14 + 4*16 = 92 g/mol

a) 1.14 moles

b) 1.14 mol*92g/mol = 104.88 g
c) 1 mol N2O4 has 4 mol O
4*1.14 = 4.56 mol
d) each O is 16 g/mol
4.56 mol*(16g/mol) = 72.96 g

Edit: nevermind. I read the question wrong. Follow Katioji answers
Please PM me if you have more questions and don't forget to rate my answer.
Mentor
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posted by Kaiouji on 8/27/2008 6:47:13 PM  |  status: Live
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tored ryan's comment:
"Thanks!!"
Response Details:
to figure out each one...

first you need to know that there is 1.14 moles of Nitrogen in the sample.

But to make the sample you need to have N2 so take 1.14/2  = 0.57

thus there is .57 moles of N2O4

therefore, the mass can be calculated by stoichiometry N2O4

so we can find moles of oxygen by stoich.
2.28 moles O
therefore the mass can be calculated to be 36.48 grams of O
Oracle
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posted by CHEMNATION! on 8/27/2008 6:57:48 PM  |  status: Live
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tored ryan's comment:
"thanks!"
Response Details:
My results concur with those of Kaiouji
Spending precious time on a problem that results in a rating of "not helpful" or "somewhat helpful" is deemed a wasted effort. With certainty, I'll be sure not to provide assistance in that direction again.
 
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