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    With naming alkanes, well hydrocarbons, I was under the impression that you took the longest chain and used that as the prefix. I'm doing exam questions rn and I'm asked to name 2 isomers of hexane but they're branched and the longest chain of carbons has 5 carbons, why is it not pentane? Am I being extremely dumb? And very sorry if this isn't worded very well!
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    (Original post by Uyirpeariel)
    With naming alkanes, well hydrocarbons, I was under the impression that you took the longest chain and used that as the prefix. I'm doing exam questions rn and I'm asked to name 2 isomers of hexane but they're branched and the longest chain of carbons has 5 carbons, why is it not pentane? Am I being extremely dumb? And very sorry if this isn't worded very well!
    I'm a bit confused about what you're asking, some of the isomers of hexane will have pentane in the name (but not just pentane since pentane only has 5 carbons so is not an isomer of hexane).
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    (Original post by Uyirpeariel)
    With naming alkanes, well hydrocarbons, I was under the impression that you took the longest chain and used that as the prefix. I'm doing exam questions rn and I'm asked to name 2 isomers of hexane but they're branched and the longest chain of carbons has 5 carbons, why is it not pentane? Am I being extremely dumb? And very sorry if this isn't worded very well!
    To be an isomer it would still have 6 carbons. So if it is branched, with the longest chain of carbons being 5, then it will still have a methyl group attached.
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    3-methylpentane is an isomer of hexane, because they have the same molecular formula. It doesn't matter that they have different names at all.
 
 
 
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