This discussion is now closed.
Check out other Related discussions
- ocr a level chemistry
- Chemistry help on benzene
- Bad interview-pharmacy
- Chemistry - Benzene
- Chemistry - organic synthesis
- A level chemistry question
- Alevel Chemistry Aromatic Compounds
- Spectroscopy help
- Connectivity chem
- Chemistry UV-vis spectrophotometer problem
- AlCl3 reacting with benzene
- AQA chem polymers quick question
- Benzene
- Chem Multiple choice % yield Q!
- chemistry help
- Make it More Hydrocarbon-ey !!
- benzene project
- Electrophillic/nucelophillic substitution /addition
- A-Level Chemistry (CAIE)
- Any Chemistry Mass Spectrum nerds help !!!!!!
Benzenes - Kekule and stability
Scroll to see replies
forgottenromeo
You can't rely on texts books, some of the things in them are wrong but we still have to answer in some of the cases, such as the exsistance of mesosomes in prokaryotic cells.
Benzene has a delocalised electron cloud, you can determine that since every bond has the same bond length (verified with x-ray diffraction) and hence is the same type of bond. It's why it's referred to as aromatic, since the delocalisation makes it more stable.
Kyle_S-C
Benzene has a delocalised electron cloud, you can determine that since every bond has the same bond length (verified with x-ray diffraction) and hence is the same type of bond. It's why it's referred to as aromatic, since the delocalisation makes it more stable.
That wasn't the arguement, the arguement was whether or not kekules structure can exsist as a molecule in its own right.
*cough-whichitcan't-cough*
evidence for the difference also comes from bond length and enthalpies of hydrogenation. benzene's bond lengths are actually intermediate between C-C and C=C. for benzene, thats the only bond length but in the kekule structure they alternate ^
also, to hydrogenate 1 C=C bond it should be around -120jkmol-1
so for benzene it should be 3 times this to hydrogenate each of the 3 bonds.. hypothetically
but the enthalpy value is different
which also proves that the kekule structure is wrong
also, to hydrogenate 1 C=C bond it should be around -120jkmol-1
so for benzene it should be 3 times this to hydrogenate each of the 3 bonds.. hypothetically
but the enthalpy value is different
which also proves that the kekule structure is wrong
Again not arguing that it is the structure of benzene, arguing that it is a feasibly possible molecule, and does rosie posie believe that world is flat, or god created man, are you completly ignorant of the idea that everything isn't what we believe and that as far as these things are concerned its just best guesses.
If you knew anything about chemistry, you would know about the movement of electrons being non-linear, you can get a cyclo-hexe-tri-ene, and because of the movement of electrons its feasible that the bonds could alternate, just because you can't prove it doesn't mean its not true.
If you knew anything about chemistry, you would know about the movement of electrons being non-linear, you can get a cyclo-hexe-tri-ene, and because of the movement of electrons its feasible that the bonds could alternate, just because you can't prove it doesn't mean its not true.
Cycloheaxtriene doesn't exist because it is benzene, things like to be stable, when given the choice a system will always chooses the lower energy configuration. As the delocalisation in benzene is much prefered energetically over seperate double and single bonds it has no reason to adopt the configuration you're suggesting. We can compare the enthalpy of hydrogenation for cyclohexene, cyclodihexene and cyclotrihexene. If there were 3 individual double bonds then cyclohexatriene = 3 x cyclohexene, but it doesn't. Oh and the movement of electrons isn't linear.
If there is no evidence to support your claim, then it means very little in science.
If there is no evidence to support your claim, then it means very little in science.
I'm not ignorant, thank you very much.
Do you have any sources which support your claim? You can't prove anything in science, but you can disprove them, and as people have already explained, the existence of Kekule can be disproved
Do you have any sources which support your claim? You can't prove anything in science, but you can disprove them, and as people have already explained, the existence of Kekule can be disproved
The non-linear arrangement was what i meant to put in referance to the over lapping p orbitals.
Cylco-hexa-tri-ene, is a feasible substance, just because it may not occur naturally on earth does not mean it doesn't exsist, and the double bonds shorten surrounding single bonds so any electrons in the p orbital would then have a good chance of over lapping, such over lapping would then cause the original double bonds to break, and cyclo-hexa-tri-ene isn't benzene, benzene is essentially a ring from graphite where the branching carbons have been replaced by hydrogen.
Cylco-hexa-tri-ene, is a feasible substance, just because it may not occur naturally on earth does not mean it doesn't exsist, and the double bonds shorten surrounding single bonds so any electrons in the p orbital would then have a good chance of over lapping, such over lapping would then cause the original double bonds to break, and cyclo-hexa-tri-ene isn't benzene, benzene is essentially a ring from graphite where the branching carbons have been replaced by hydrogen.
RosiePosiePuddingAndPie
I'm not ignorant, thank you very much.
Do you have any sources which support your claim? You can't prove anything in science, but you can disprove them, and as people have already explained, the existence of Kekule can be disproved
Do you have any sources which support your claim? You can't prove anything in science, but you can disprove them, and as people have already explained, the existence of Kekule can be disproved
The fact the world is spherical was disproved, the fact the earth orbits round the sun was disproved. Once again with our current level of technology and scientific knowledge we can only surmise what benzenes structure is, we can't even fathom structures in places other than earth, and in most cases theorise what they may be. There is enough evidence to say that kekules model EVEN THOUGH IT MAY NOT BE BENZENE is feasible as a molecule.
forgottenromeo
Again not arguing that it is the structure of benzene, arguing that it is a feasibly possible molecule, and does rosie posie believe that world is flat, or god created man, are you completly ignorant of the idea that everything isn't what we believe and that as far as these things are concerned its just best guesses.
If you knew anything about chemistry, you would know about the movement of electrons being linear, you can get a cyclo-hexe-tri-ene, and because of the movement of electrons its feasible that the bonds could alternate, just because you can't prove it doesn't mean its not true.
If you knew anything about chemistry, you would know about the movement of electrons being linear, you can get a cyclo-hexe-tri-ene, and because of the movement of electrons its feasible that the bonds could alternate, just because you can't prove it doesn't mean its not true.
It cannot exist since it is a combination of the same atoms as benzene in the same configuration, hence it is benzene. It may be possible to use an atomic force microscope or something to break benzene's planar structure and break its aromaticity.
Kyle_S-C
It cannot exist since it is a combination of the same atoms as benzene in the same configuration, hence it is benzene. It may be possible to use an atomic force microscope or something to break benzene's planar structure and break its aromaticity.
The cyclination of 1,3,5 hexa-tri-ene would produce a kekule structure even if only for fractions of a second, which if it is long enough to determine the exsistance of an element should be long enough to classify it as a feasible molecule.
forgottenromeo
The fact the world is spherical was disproved, the fact the earth orbits round the sun was disproved. Once again with our current level of technology and scientific knowledge we can only surmise what benzenes structure is, we can't even fathom structures in places other than earth, and in most cases theorise what they may be. There is enough evidence to say that kekules model EVEN THOUGH IT MAY NOT BE BENZENE is feasible as a molecule.
So basically you have no proof, you've just decided that it exists?
We're talking about modern science, not Tudors deciding that the world is flat or something...
RosiePosiePuddingAndPie
So basically you have no proof, you've just decided that it exists?
We're talking about modern science, not Tudors deciding that the world is flat or something...
We're talking about modern science, not Tudors deciding that the world is flat or something...
And your proof being what exactly? That some scientists did some tests which prove that its not the structure of one thing, and theorised that it could be a ring of delocalised electrons? Thats such a great founding there. With the exception of kyle i seriously hope none of you are planning to go into research fields. Tell me do you support string theory? do you believe that to be truth and solid fact? There is no solid proof to the structure of benzene, there is experimental tests, but with out being able to actually see it there is no difinitive proof that it is the way it is. If you can't get your head round the notion that not everything you are told is true, or the full truth then you must have been asleep through any chemistry lessons you supposedly attended. I'm not just deciding that it exsists i'm stating that it is feasible, and for those of you how don't grasp this notion, i mean that under some circumstance at some point no matter how short the space of time. That it is possible that it COULD exsist.
forgottenromeo
Kekules model is an actual substance
oh really?
forgottenromeo
it can be proved to exsist.
you sure?
forgottenromeo
Its plausible though
so what now it doesn't?
forgottenromeo
kekules structure can exsist as a molecule in its own right.
oh right...
forgottenromeo
it COULD exsist.
could?
Your clearly an intelligent guy, i'm not disputing this, but on this particular subject you are quite wrong. This is not some abstract field, its basic chemistry, benzene has been studied to death. You're correct in that nothing can ever really be proved (except in abstract math), however things can be proved 'beyond reasonable doubt'. There are cyclic molecules with alternating double bonds that are not delocalised, C6H6 is not one of them. It has been reacted with a huge vareity of things, heated well beyond its boiling point, zaped with light/lasers, cooled down to approaching absolute zero...so it's reasonable to suggeest that its just not there.
To your other point, i happen to be in a research field, this one in fact. And the thing that really hampers research progress is not lack of thought, but the unwilligness to accept that something isn't going to work and to waste further time pursuing it. I'm just trying to help you, i'm sorry that you don't see that...
Really, so you are saying that in your research lap you have every piece of equipment that can ever be created, and can create every possible circumstance. No matter how good your research team and equipment is you can't completely discredit anything. You can only say that within the limits of our capabilities to study it is impossible. My entire arguement from start to finish is that it is an actual substance, that could be created in the right circumstances, creative quoting doesn't change what i was trying to get across. The possibility that it exsists and we haven't been able to study it because it is so unstable doesn't detract from the fact that it exsists such as the artificial elements which are recognised the world round, but only exsist for a fraction of a second.
And math can never be proven as to prove math you are required to use math, and you can't prove something using itself.
EDIT: Heating and cooling is well and good, what about under great pressure, such as jupiters core, or in the center of a sun, what about on the verges of a neutrino star, the hearts of asteroids (in which organic molecules have been found), under the ice of jupiters frozen moon, or in a star factory? Do you have solid scientific evidence to prove that it could never possibly exsist in places such as these.
And math can never be proven as to prove math you are required to use math, and you can't prove something using itself.
EDIT: Heating and cooling is well and good, what about under great pressure, such as jupiters core, or in the center of a sun, what about on the verges of a neutrino star, the hearts of asteroids (in which organic molecules have been found), under the ice of jupiters frozen moon, or in a star factory? Do you have solid scientific evidence to prove that it could never possibly exsist in places such as these.
RosiePosiePuddingAndPie
I'm not ignorant, thank you very much.
Do you have any sources which support your claim? You can't prove anything in science, but you can disprove them, and as people have already explained, the existence of Kekule can be disproved
Do you have any sources which support your claim? You can't prove anything in science, but you can disprove them, and as people have already explained, the existence of Kekule can be disproved
I think there is plenty of evidence kekule exsisted he was a well renowned scientist.
To say it exists because we can't detect it is bit of a fallacy. Does that mean the flying sphagetti monster in your backyard is real? I mean, you can't detect it, so it must be there, right?
"There's no evidence it doesn't exist" and "you can't prove it doesn't exist" are the types of argument a religous fundementalist uses, not a scientist. The simple fact is, you cannot prove a negative (think of Russel's teapot).
"There's no evidence it doesn't exist" and "you can't prove it doesn't exist" are the types of argument a religous fundementalist uses, not a scientist. The simple fact is, you cannot prove a negative (think of Russel's teapot).
I'm not saying it exists because we can't prove it doesn't exist, i'm saying you can't say it doesn't exist because we can't prove beyond doubt that it doesn't exsist therefore its FEASIBLE or POSSIBLE that it exists.
Well you're right in the sense that we can't know everything, taken. But you can't claim something for which you have no theoretical or practical evidence for. Science works on a system realting to the burden of proof, you can make any claim you want, but in order for anyone rational to believe you you'll have to back it up. So far the evidence is stacked against your assertion. Also in most of the situations (extreme pressures and temperatures) you've described there would be more than enough energy to break any molecule apart (side note: organic molecules have been found in the vast gaps between galaxies too that couldn't exist in standard conditions). As far as i understand it things can be proved IN math, i'm not suggesting that math can be proved as an entity.
Ok.
"To say it MIGHT exist because we can't detect it is bit of a fallacy. Does that mean the flying sphagetti monster in your backyard is real? I mean, you can't detect it, so it MIGHT be there right?
"There's no evidence it doesn't exist" and "you can't prove it doesn't exist" are the types of argument a religous fundementalist uses, not a scientist. The simple fact is, you cannot prove a negative (think of Russel's teapot)."
This is really a pointless discussion. We can argue all day that something is FEASIBLE or POSSIBLE when we're basing it on zero observations (and ignoring observations that predict the contary). Whether it exists or not is of little importance, since if it does, it'll immediately go to it's most stable form i.e. benzene.
"To say it MIGHT exist because we can't detect it is bit of a fallacy. Does that mean the flying sphagetti monster in your backyard is real? I mean, you can't detect it, so it MIGHT be there right?
"There's no evidence it doesn't exist" and "you can't prove it doesn't exist" are the types of argument a religous fundementalist uses, not a scientist. The simple fact is, you cannot prove a negative (think of Russel's teapot)."
This is really a pointless discussion. We can argue all day that something is FEASIBLE or POSSIBLE when we're basing it on zero observations (and ignoring observations that predict the contary). Whether it exists or not is of little importance, since if it does, it'll immediately go to it's most stable form i.e. benzene.
Related discussions
- ocr a level chemistry
- Chemistry help on benzene
- Bad interview-pharmacy
- Chemistry - Benzene
- Chemistry - organic synthesis
- A level chemistry question
- Alevel Chemistry Aromatic Compounds
- Spectroscopy help
- Connectivity chem
- Chemistry UV-vis spectrophotometer problem
- AlCl3 reacting with benzene
- AQA chem polymers quick question
- Benzene
- Chem Multiple choice % yield Q!
- chemistry help
- Make it More Hydrocarbon-ey !!
- benzene project
- Electrophillic/nucelophillic substitution /addition
- A-Level Chemistry (CAIE)
- Any Chemistry Mass Spectrum nerds help !!!!!!
Latest
Trending
Last reply 1 week ago
Im confused about this chemistry question, why does it form these productsTrending
Last reply 1 week ago
Im confused about this chemistry question, why does it form these products
