#1
I failed a chemistry course a year ago that I don't really need but that would be useful to have, so I have decided to study during the summer to retake the final exam this fall. I got stuck on this question early on, any help solving it would be appreciated.

Cholorine has two naturally occurring isotopes,

35Cl (35 would be the mass number), isotopic mass 34,9689 amu (Da) and
37Cl, isotopic mass 36,9659 amu.

If chlorine has an atomic mass of 35,4527 amu, what is the percent abundance of each isotope?

thanks in advance
#2
its infinity.
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#3
You can't call something "fairly easy" if you can't do it yourself

I'm sorry - I can't do Chemistry. Good luck in Chemistry though
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#5
We're geeks in guitar, not geeks in Chemistry!
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#6
I said it was fairly easy because for anyone who has studied chemistry it probably is. I just started out though, and I am not very good at it.

aww, I've seen harder questions than this answered here, so I am sure there's someone out there.
#7
Quote by visionen
I said it was fairly easy because for anyone who has studied chemistry it probably is. I just started out though, and I am not very good at it.

This is bloody killing me, I'm taking chemistry and I should be able to do this, but alas it's summer and my mind is switched off.
#8
The answer is Jeff Loomis.

I'm kidding, I dont know, Chemistry hurt my brain when I took it.
#9
i cant remember exactly how to do this (mostly because i have a headache and it would take a lot of effort to try to remember), but could you not find the difference between each of the isotopic masses and the atomic mass, take these numbers as a ratio to each other, convert it to a percentage?
probably doesnt work, but sure worth a go. sorry i cant be more help
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#10
its a fairly simple problem actually. you more or less have to get them to average together to be that number. ill do the numbers in just a minute..
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#11
Quote by blynd_snyper
This is bloody killing me, I'm taking chemistry and I should be able to do this, but alas it's summer and my mind is switched off.



I know how you feel. Perhaps its not that easy, I sort of assumed it should be though because its the first chapter.
#12
Quote by ZoSoII_13
its a fairly simple problem actually. you more or less have to get them to average together to be that number. ill do the numbers in just a minute..



thanks!
#13
i got a ratio of about 3.12:1. so thats what, a little less than 25% Cl37, little more than 75% Cl35?
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#15
sorry, 32% and 68%. again, sorry if thats wrong, but i havent done chemistry in a few months!
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#17
its about 76% of the smaller isotope and 24% of the larger one. thats not exact, but its close enough
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#18
Quote by el-gilberto
sorry, 32% and 68%. again, sorry if thats wrong, but i havent done chemistry in a few months!


the first one was right
#19
ah sh1t, i was right first time?
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#20
Quote by ZoSoII_13
its about 76% of the smaller isotope and 24% of the larger one. thats not exact, but its close enough


Thanks

Quote by el-gilberto
ah sh1t, i was right first time?


yup
#21
ok, so 35.4527 - 34.9689 = 0.4838 <---atomic mass - smaller isotope
36.9659 - 35.4527 = 1.5132 <--- larger isotope - atomic mass
these are the differences between isotope masses and atomic mass

1.5132/0.4838 = 3.1278 <---your ratio right there
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Last edited by el-gilberto at Jul 30, 2008,
#23
to find it, you set up a ratio of each isotopes respective differences from the original 354527. the first isotope is 4838 from that number, and the second is 15132 from the number. set up a proportion:

15132/4838 = x/1

x=3.12

therefore there is 312% more of the first isotope present than the second, and the resulting percentages are 75.7% of the first, and 24.3% of the second.
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#25
Quote by ZoSoII_13
to find it, you set up a ratio of each isotopes respective differences from the original 354527. the first isotope is 4838 from that number, and the second is 15132 from the number. set up a proportion:

15132/4838 = x/1

x=3.12

therefore there is 312% more of the first isotope present than the second, and the resulting percentages are 75.7% of the first, and 24.3% of the second.


high 5!! go team chemistry
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#26
2 sides of the atlantic, same process.
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