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.
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.
So butene does not exist? Can you get ethene on its own or would it be 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?
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?
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
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.
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. Isomers and being able to identify more complex structures too.. you'll learn as you go on.
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
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.
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.
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
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.
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.
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
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