Exercise 1.11 b Systematic Names of stuctures

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Shannon Han 2B
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Exercise 1.11 b Systematic Names of stuctures

Postby Shannon Han 2B » Wed Mar 04, 2015 7:32 pm

I'm confused on #1.11b where it asks you to draw a line structure and give the systematic name for CH3(CH2)3 CHCHCH3. I thought the 3 CH2's in the parentheses would be substituents, but why are they included as part of the parent chain?

Chem_Mod
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Re: Exercise 1.11 b

Postby Chem_Mod » Wed Mar 04, 2015 10:25 pm

When you see (CH2)n in a condensed structure, it just means repeating units of straight chain carbon. The end carbons, which are CH3 and not CH2, are not included in the parentheses.

So CH3-(CH2)3-CH3 is pentane, since 3 units of straight chain + 2 end carbons = 5 total carbons.

CH3(CH2)3 CHCHCH3 is 2-heptene, since you can find 7 total carbons, but the lack of hydrogens at "CH CH" indicates a double bond.

Justin Le 2I
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Re: Exercise 1.11 b

Postby Justin Le 2I » Thu Mar 05, 2015 1:07 am

Adding onto what Chem Mod said above, if you see CC then there is probably a triple bond and the structure is an alkyne.


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