stuck please help me organic chemistry Watch

usernamenew
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im finding it very confusing when some molecules have the alkyl ethyl yet in molecules only methyls are named and no ethyl
but in this example I don't know why theyve used ethyl
the answer is 4-ethyl-4-methylheptane
I drew the molecule out and both the ch2ch3 (ethyl?) and ch2ch2ch3 is on carbon 4, in other examples where there is ch2ch3 on one carbon they use only methyl not ethyl, so I'm really confused as to why here they use ethyl in this case but not in any other examples
i hope i explained that clearly
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usernamenew
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(Original post by usernamenew)
im finding it very confusing when some molecules have the alkyl ethyl yet in molecules only methyls are named and no ethyl
but in this example I don't know why theyve used ethyl
the answer is 4-ethyl-4-methylheptane
I drew the molecule out and both the ch2ch3 (ethyl?) and ch2ch2ch3 is on carbon 4, in other examples where there is ch2ch3 on one carbon they use only methyl not ethyl, so I'm really confused as to why here they use ethyl in this case but not in any other examples
i hope i explained that clearly
please could omeone help me
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ROadmanKys
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so firstly, identify the longest Carbon chain, which is heptane (7carbons)
the carbon which has 2 function groups coming off of it, is 4, no matter which way you start counting from in that 7 carbon chain you've identified. The heaviest chain has to be named first, so the ethyl then methyl. hence the 4-ethyl-4-methyl-heptane.

if there was a halogen they would take priority etc. im sure you know from nomenclature. if not, i'd recommend reading on chemrevise for notes and use revisely for the notes to be at one site.
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usernamenew
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(Original post by ROadmanKys)
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so firstly, identify the longest Carbon chain, which is heptane (7carbons)
the carbon which has 2 function groups coming off of it, is 4, no matter which way you start counting from in that 7 carbon chain you've identified. The heaviest chain has to be named first, so the ethyl then methyl. hence the 4-ethyl-4-methyl-heptane.

if there was a halogen they would take priority etc. im sure you know from nomenclature. if not, i'd recommend reading on chemrevise for notes and use revisely for the notes to be at one site.
thank u so much!! if halogens were used, do u just name the molecule in alphabetical order? is that what u mean?
is it possible if u could help me on another question please?
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ROadmanKys
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just post it.
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Anonymouspsych
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(Original post by usernamenew)
please could omeone help me
The stem of the name comes from the longest chain- in this case the longest chain has 7 carbons so it will have a stem of heptane. You can see that on the 4th carbon along from either end of the longest chain, there is a methyl and an ethyl group attached.

hence the IUPAC name would be 4-ethyl-4-methylheptane
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