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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Violet89 on February 13, 2012, 05:14:23 AM

Title: Atoms to Molecules Answer Check
Post by: Violet89 on February 13, 2012, 05:14:23 AM
If a sample of butane, C4H10, contains a total of 8.0 X 10^3 atoms of carbon, how many molecules of butane are in the sample?


8.0 X 10^3 atoms C * (1 formula unit C4H10 / 4 C atoms) * (6.022 X 10^23 C4H10 molecules / 1 formula unit C4H10) = 1.2 X 10^27 molecules C4H10


Is this correct?
Title: Re: Atoms to Molecules Answer Check
Post by: sjb on February 13, 2012, 05:20:12 AM
Quote from: valerieangel23 on February 13, 2012, 05:14:23 AM
If a sample of butane, C4H10, contains a total of 8.0 X 103 atoms of carbon, how many molecules of butane are in the sample?


8.0 X 103 atoms C * (1 formula unit C4H10 / 4 C atoms) * (6.022 X 1023 C4H10 molecules / 1 formula unit C4H10) = 1.2 X 1027 molecules C4H10


Is this correct?

Not quite, no. Why have you multiplied by Avogadro's number (what are it's units?)
Title: Re: Atoms to Molecules Answer Check
Post by: Violet89 on February 13, 2012, 05:48:37 AM
Quote from: sjb on February 13, 2012, 05:20:12 AM
Quote from: valerieangel23 on February 13, 2012, 05:14:23 AM
If a sample of butane, C4H10, contains a total of 8.0 X 103 atoms of carbon, how many molecules of butane are in the sample?


8.0 X 103 atoms C * (1 formula unit C4H10 / 4 C atoms) * (6.022 X 1023 C4H10 molecules / 1 formula unit C4H10) = 1.2 X 1027 molecules C4H10


Is this correct?

Not quite, no. Why have you multiplied by Avogadro's number (what are it's units?)

Thanks for the reply. Would you simply divide 8.0 X 10^3 by 4 then?
Title: Re: Atoms to Molecules Answer Check
Post by: Borek on February 13, 2012, 06:49:46 AM
Yes.
Title: Re: Atoms to Molecules Answer Check
Post by: Violet89 on February 13, 2012, 07:19:56 PM
Quote from: Borek on February 13, 2012, 06:49:46 AM
Yes.

Thank you.  :)