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Naming of isomers....

I have enclosed a picture of a hydrocarbon.

So far I have identified that it is 2-methyl. (2 because the branch I started numbering the carbon atoms from the left hand side; as this was closest to the branch.) The methyl is because the branch contains 1 Carbon to 3 Hydrogen; satisfying the CH3 requirement.

I am unsure as to the rest.
(edited 9 years ago)
hydrocarbon.png1.5KB
You have a 4 carbon chain which makes it butane and then you have a methyl on the second carbon making it 2methyl-pentane

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Reply 2
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User947387
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I took that from the BBC bitesize; they say that it is 2methyl-butane :|
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Original post by apronedsamurai
I took that from the BBC bitesize; they say that it is 2methyl-butane :|

That's right. The butane bit comes from the fact that there are 4 carbons in a chain. Even though there's 5 all together
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So where did the pentane come from?

So, to clarify. When naming an isomer, you count the carbons in the chain; (exclude the carbons in the branches); and from there, name the compound accordingly?

I had thought it was Butane, because there were 4 carbons; but when I counted the hydrogen atoms there was one missing; i.e. only 9 (if I excluded the hydrogen atoms on the branch, if I were to include them in the computation there would be a total of 12) Butane however is C4H10....so that was the basis of my confusion
(edited 9 years ago)
Original post by apronedsamurai
So where did the pentane come from?

So, to clarify. When naming an isomer, you count the carbons in the chain; (exclude the carbons in the branches); and from there, name the compound accordingly?

I had thought it was Butane, because there were 4 carbons; but when I counted the hydrogen atoms there was one missing; i.e. only 9 (if I excluded the hydrogen atoms on the branch, if I were to include them in the computation there would be a total of 12) Butane however is C4H10....so that was the basis of my confusion


Yeah now that I look at it im really sorry I made a mistake

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TajwarC
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Original post by apronedsamurai
So where did the pentane come from?

So, to clarify. When naming an isomer, you count the carbons in the chain; (exclude the carbons in the branches); and from there, name the compound accordingly?

I don't know where the other person found pentane from.

1) find your longest carbon chain (they aren't always in a straight line however so be careful)
2) count the carbons on that chain
3) the number of carbons is the alkane part i.e 1=meth-, 2= eth-, 3=prop-, etc
4) identify the methyl (alkyl) groups. The number that goes in front is the number of the carbon it is attached to

in your case there are 4 carbons in a chain, therefore it will be butane. On the second there is a methyl group thus it is 2methyl-butane
(edited 9 years ago)
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Original post by frances98
Yeah now that I look at it im really sorry I made a mistake

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Hey, I just appreciate people taking the time to respond to my questions. :smile:
Original post by apronedsamurai
Hey, I just appreciate people taking the time to respond to my questions. :smile:


Hi I know I had it right at the start but then for some reason changed my answer :facepalm:

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