What are these organic molecules names? You have to use FULL nomenclature.
1) H3C – CH = CH – CH – CH3
What is the full nomenclature for question 1?
For the next question below why is the answer 2,3-dimethyl-2-butene and not 2,3-dimethyl but 2 ene?
2) H3C-C(CH3)=C(CH3)-CH3
1) H3C – CH = CH – CH – CH3
What is the full nomenclature for question 1?
I would name 1) as 2-pentene.
For the next question below why is the answer 2,3-dimethyl-2-butene and not 2,3-dimethyl but 2 ene?
2) H3C-C(CH3)=C(CH3)-CH3
Because the name I gave it, which I understand is still a good name, is an older system that was replaced by IUPAC in 1995 with
2,3-dimethyl-but-2 ene (note that I added in the dashes you omitted). I don't know why the IUPAC chose to change that rule. The new rule has gained acceptance through the years but I understand it was not accepted very well at the beginning. You will note that I have prefaced all of my answers with "I would name this as" because that's what "I" would name them. I chose not to try and name them using the new terms of 1995 BECAUSE I haven't tried to name an organic compound in 50 or 60 years and to be perfectly honest about it I wouldn't bet the farm that I named any of those compounds correctly. That said, I have had absolute no experience naming compounds by the new1995 rules. My best guess is that any of those compounds with a double bond should be named similarly to the name you gave to the but-2-ene compound; i.e., using the system in place after 1995. I don't think that makes my name wrong; it just means the name I gave it is outdated by 25 year or so. :-)
1) Is it not 2-butene?
Someone said it would be 2-butene for question 1 but I do not understand how when there are 5 carbons. Maybe that is wrong?
2) I wrote down 2,3-dimethyl-2-butene which is the answer you gave.
I saw a website that said this:
2,3-Dimethyl-2-butene C6H12
2,3-Dimethylbut-2-ene;hydrogen peroxide C6H14O2
This confused me even more. Can you please explain.
No, there are 4 carbons in the chain. In the condensed formula I have tried to number the carbons by showing the ones in the chain as bold face. The carbons you are counting to make it more than 4 are the side chains (the dimethyl part). As for the empirical formula of C6H12, the butene is 4 carbons and the two dimethy make 6. If you count the H atoms there are 12 which is right for a 1 double bond structure which is CnH2n or C6H12. Then if you add H2O2 to the C6H12 you get C6H14O2
H3C-C(CH3)=C(CH3)-CH3
Hope this helps.
1) H3C – CH = CH – CH – CH3
What is the full nomenclature for question 1?
You said you would name this 2-pentene.
Someone said it would be 2-butene for question 1 as their answer on a website but I do not understand how when there are 5 carbons. Maybe what they said is wrong?
2) I wrote down 2,3-dimethyl-2-butene which is the answer you gave. So would this be the right answer and 2,3-dimethylbut-2-ene is wrong? They are both different?
1) H3C - CH = CH - CH - CH3
What is the full nomenclature for question 1?
You said you would name this 2-pentene.
Wouldn't 2-pentene be H3C − CH = CH − CH2 − CH3 ?
Yes, 2-pentene is what you wrote. I went back and looked at the original question. I saw 2-pentene but now that I look again I see a trivalaent C so I don't know what to name it. As for the other part of that question I didn't answer; i.e.,2) I wrote down 2,3-dimethyl-2-butene which is the answer you gave. So would this be the right answer and 2,3-dimethylbut-2-ene is wrong? They are both different?
No, they are not different. Both are correct names. I named it by the older IUPAC rules and the other is named by the newer rules (after 1995). Personally I think either name is correct but the real up to date organic profs may not agree with me. If you want to be up to date you would name it the latter; i.e., 2,3-dimethyl-but-2-ene.. Also, you would follow that same set of rules for the other alkenes you have listed in the last several days. BTW, I am having trouble following the thread. I suggest you start a new thread if you have follow ups.
1) The full nomenclature for the organic molecule H3C – CH = CH – CH – CH3 is 1-pentene.
To determine the full nomenclature, you need to identify the longest carbon chain and number the carbons from one end to the other. In this case, the longest carbon chain contains five carbons.
You start numbering from the end closest to the first double bond. In this molecule, the double bond is between the first and second carbon. So, starting from the end closest to the double bond, the first carbon is numbered as one.
Then, you name the substituents on the main chain. In this case, there is one methyl group attached to the third carbon. So, the full nomenclature is 1-pentene.
2) The full nomenclature for the organic molecule H3C-C(CH3)=C(CH3)-CH3 is 2,3-dimethyl-2-butene.
To determine the full nomenclature, you need to identify the longest carbon chain and number the carbons from one end to the other. In this case, the longest carbon chain contains four carbons.
You start numbering from the end closest to the first double bond. In this molecule, the double bond is between the second and third carbon. So, starting from the end closest to the double bond, the second carbon is numbered as one.
Then, you name the substituents on the main chain. In this case, there are two methyl groups attached to the second and third carbons. So, the full nomenclature is 2,3-dimethyl-2-butene.
The term "butene" indicates that the molecule contains a four-carbon chain with one double bond, and the prefixes "2,3-dimethyl" specify the positions and number of methyl groups on the chain.
If the molecule were named as "2,3-dimethylbut-2-ene," it would imply a five-carbon chain with two methyl groups attached to the second and third carbons and one double bond between the second and third carbons. However, that is not the case in this molecule, so the correct full nomenclature is 2,3-dimethyl-2-butene.