Physics Forums (http://www.physicsforums.com/index.php)
-   Biology, Chemistry & Other Homework (http://www.physicsforums.com/forumdisplay.php?f=157)

 priscilla89 Dec24-10 10:23 AM

Percent Composition

1. The problem statement, all variables and given/known data

What is the percentage of carbon in dimethylsulfoxide, C2 H6 SO4?

2. Relevant equations

mass of C / total mass x 100 = percentage of carbon

3. The attempt at a solution

The total mass = 126

total mass of C = 24

Wouldn't it be 24 / 126 x 100 = 19 %

But somehow I got this wrong, it's 30.7 %

Any help will be appreciated, thanks a lot

 sjb-2812 Dec24-10 10:33 AM

Re: Percent Composition

Quote:
 Quote by priscilla89 (Post 3051712) 1. The problem statement, all variables and given/known data What is the percentage of carbon in dimethylsulfoxide, C2 H6 SO4? 2. Relevant equations mass of C / total mass x 100 = percentage of carbon 3. The attempt at a solution The total mass = 126 total mass of C = 24 Wouldn't it be 24 / 126 x 100 = 19 % But somehow I got this wrong, it's 30.7 % Any help will be appreciated, thanks a lot
Are you sure of your formula for dimethyl sulfoxide?

 priscilla89 Dec24-10 10:49 AM

Re: Percent Composition

Quote:
 Quote by sjb-2812 (Post 3051720) Are you sure of your formula for dimethyl sulfoxide?
Yes, but I think somehow it's the formula that's wrong.

 sjb-2812 Dec24-10 10:56 AM

Re: Percent Composition

No, if you are happy that the chemical formula you have given is correct, the maths is also correct. However, see e.g. http://en.wikipedia.org/w/index.php?...ldid=399297621 or similar.

 priscilla89 Dec24-10 11:06 AM

Re: Percent Composition

Quote:
 Quote by sjb-2812 (Post 3051746) No, if you are happy that the chemical formula you have given is correct, the maths is also correct. However, see e.g. http://en.wikipedia.org/w/index.php?...ldid=399297621 or similar.
But the formula has to be (CH3)2 SO.

24 / 78 x 100 = 30.7 %

- thanks a lot and happy holidays

 All times are GMT -5. The time now is 09:25 PM.