Any Difference between 'butene' and 'but-1-ene'?

The 1 just lets you know that the double bond is on the first carbon.

Would you ever say butene independently?

No, I think you always write the 1 or else it's wrong.

Is that what you're asking?

The 1 just lets you know that the double bond is on the first carbon.

Would you ever say butene independently?

Presuming this is for GCSE/A levels, I would just play it safe and call it But-1-ene. Rationale behind it is to have the ability to distinguish between say, But-1-ene & But-2-ene.

Otherwise no, there's no difference.

I think so?

xD Organic chem at crack of dawn <3

So butene does not exist? Can you get ethene on its own or would it be eth-1-ene?

Thank you, great

Would you say ethene or eth-1-ene?

No, ethene is just ethene, because the double bond won't move or change. So no need to distinguish it. But with But-1-ene or But-2-ene, it has moved, do you see what I mean?

Ethene would be a different case since there's no possiblity of the C=C to exist anywhere else.. so no, I would just call it ethene.

Thannks just to clarify:

Ethene is a special case.

Then after that carbons that there are more of 3 you must name with respect to the double bond, i.e. 1,2 etc. and you always name from the first carbon you touch - i.e. double bond between 2 and 3 then it will be xxx-3-ene.

I believe I understand you guys, you double this so you give each compound a specified name, so you can distinguish it in case of isomers etc. right?

Thanks for your help.

Thannks just to clarify:

Ethene is a special case.

Then after that carbons that there are more of 3 you must name with respect to the double bond, i.e. 1,2 etc. and you always name from the first carbon you touch - i.e. double bond between 2 and 3 then it will be xxx-3-ene.

I believe I understand you guys, you double this so you give each compound a specified name, so you can distinguish it in case of isomers etc. right?

Thanks for your help.

I'm afraid your question has confused me what do you mean with the two parts I have highlighted, can you make it any clearer for me please?! and then maybe I can help you

Double bond between a second and third carbon would be xxx-2-ene, not 3-ene. You number the first carbon affected. xxx-3-ene would be the double bond between the third and fourth (providing this goes higher than four carbons).

So..

Ethene: C=C

Prop-1-ene: C=C-C

But-1-ene: C=C-C-C or C-C-C=C

But-2-ene: C-C=C-C

Pent-1-ene: C=C-C-C-C

Pent-2-ene: C-C=C-C-C or C-C-C=C-C

Hex-1-ene: C=C-C-C-C-C

Hex-2-ene: C-C=C-C-C-C or C-C-C-C=C-C

Hex-3-ene: C-C-C=C-C-C

But yeah apart from that you're right

Thank you that is what I meant, sorry!

Finally last question on this for something like hex-1-ene in your example
:

It can be: Hex-1-ene: C-C-C-C-C=C too right?

And ethene is the only alkene without a number attached to it, since there is no choice for where the double bond must lie.

Therefore you can't get hexene?

Thanks for your effort

Sorry,

So you can't get methene.

Ethene is the only possible type of alkene.

Then the naming process begins, of double bonds depending on where the carbon atom is since there are more than 2 carbon atoms.

I don't know what double means either ffs. Sorry.

Essentially yes.

I'd argue Propene too, but that's something you should confirm with a teacher because I'm not sure what the mark schemes ask for nowadays.

As compounds become more complex, it becomes important to identify the double bonds. So when more elements or methyl groups are added - numbering becomes even more important.

Remember the basics and stick to that, when you come across the more complicated ones these should make sense.

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and

[video="youtube;dsQlK6in-XM"]https://www.youtube.com/watch?v=dsQlK6in-XM[/video]

Thanks guys, really improved my understanding.

So for something such as:

methylpropane:


Where is the methyl group because CH3 CH2 CH2 CH3 is just butane, how am I supposed to know where it goes without a number associated with it. Thanks.

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There isn't, I meant to say that in the future when you come across them you'll need to be able to name and identify these double bonds correctly.

Wouldn't worry about it now tbh

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Right yes, thanks.

But for the example of Methylpropane: Would it be: CH3-CH(CH3)-CH3

That would be 2-methylpropane.

Because you could have (for example) 1-bromo, 2-methylpropane if you were to add a bromine group to the first carbon right? So you need to be specific for anything above ethane

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