Enantiomer/ Conformational Isomer?

[Dencology]

Guys, enantiomers have the same physical and chemical property but they rotate differently around polarized plane. they have the same atomes but they are bonded differently. Now for conformational isomers, everything is the same in terms of their connectivity and physical and chemical property, so why the answer to this question is A instead of D?

A Two isomers of the same molecular formula are closest in physical and chemical properties when jointly exhibiting
A. conformational isomerism. B. constitutional isomerism. C. geometric isomerism. D. enantiomeric isomerism. E. diastereomeric isomerism.

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[myair]

Guys, enantiomers have the same physical and chemical property but they rotate differently around polarized plane. they have the same atomes but they are bonded differently. Now for conformational isomers, everything is the same in terms of their connectivity and physical and chemical property, so why the answer to this question is A instead of D?

A Two isomers of the same molecular formula are closest in physical and chemical properties when jointly exhibiting
A. conformational isomerism. B. constitutional isomerism. C. geometric isomerism. D. enantiomeric isomerism. E. diastereomeric isomerism.

B. constitutional isomerism

 

[Sublimation]

Guys, enantiomers have the same physical and chemical property but they rotate differently around polarized plane. they have the same atomes but they are bonded differently. Now for conformational isomers, everything is the same in terms of their connectivity and physical and chemical property, so why the answer to this question is A instead of D?

A Two isomers of the same molecular formula are closest in physical and chemical properties when jointly exhibiting
A. conformational isomerism. B. constitutional isomerism. C. geometric isomerism. D. enantiomeric isomerism. E. diastereomeric isomerism.

Enantiomers are very different in their physical properties. take Limonene(wiki it) for example, one enantiomer gives you a citrus like scent while the other gives u a very pungent scent, very repulsive. Limonene is found in alot of citrus fruits (oranges). In regards to the Question above, enantiomers and diasteriomers are very different in their physical properties, cross out D and E. for C you know its gonna be different due to the difference in the boiling points of Di Tri and Tetra subsituted molecules and their heat of hydrogenation. Therefore C is out of the Question. Now B isnt the answer because constitutional isomers differ in the sequence of the molecules. therefore all ur left with is a conformational isomer. when a molecule spins about a sigma bond u form a conformer. check the document it will make alittle more sense.

 

[Dencology]

Enantiomers are very different in their physical properties. take Limonene(wiki it) for example, one enantiomer gives you a citrus like scent while the other gives u a very pungent scent, very repulsive. Limonene is found in alot of citrus fruits (oranges). In regards to the Question above, enantiomers and diasteriomers are very different in their physical properties, cross out D and E. for C you know its gonna be different due to the difference in the boiling points of Di Tri and Tetra subsituted molecules and their heat of hydrogenation. Therefore C is out of the Question. Now B isnt the answer because constitutional isomers differ in the sequence of the molecules. therefore all ur left with is a conformational isomer. when a molecule spins about a sigma bond u form a conformer. check the document it will make alittle more sense.

i don't agree with you. If you take a look at this http://en.wikipedia.org/wiki/Enantiomer then you will see that enantiomers have the same physical and chemical property. also take a look at kaplan book page 254 at the bottom. it tells you exactly the enantiomers have identical properties except for optical activity.

so i guess something is missing here.

 

[Sublimation]

i don't agree with you. If you take a look at this http://en.wikipedia.org/wiki/Enantiomer then you will see that enantiomers have the same physical and chemical property. also take a look at kaplan book page 254 at the bottom. it tells you exactly the enantiomers have identical properties except for optical activity.

so i guess something is missing here.

"Enantiomers are very different in their Chemical* properties" oops sorry about that. Thats weird, im almost certain i had gotten two forms of limonene when i extracted it for research. One smelled like citrus fruit and one smelled very pungent and repulsive. My professor had said they were enantiomers, sorry i must have heard him wrong. However, the question still asks it wants something with the same physical and chemical properties. The way a molecule bends polarized is a chemical property. Therefore A is stillthe right answer choice.

 

[IWantSmile]

"Enantiomers are very different in their Chemical* properties" oops sorry about that. Thats weird, im almost certain i had gotten two forms of limonene when i extracted it for research. One smelled like citrus fruit and one smelled very pungent and repulsive. My professor had said they were enantiomers, sorry i must have heard him wrong. However, the question still asks it wants something with the same physical and chemical properties. The way a molecule bends polarized is a chemical property. Therefore A is stillthe right answer choice.

eeek, now I am getting really confused. When I looked into wiki/ enantiomers, it said "Enantiomers of each other often do have different chemical properties related to other substances that are also enantiomers. Since many molecules in the bodies of living beings are enantiomers themselves, there is often a marked difference in the effects of two symmetrical enantiomers on living beings,"... so I guess you were right at first answer, Sublimation. Anyone help ? more explanation contrbutions here?

Thanks in advance.

 

[franklinave]

eeek, now I am getting really confused. When I looked into wiki/ enantiomers, it said "Enantiomers of each other often do have different chemical properties related to other substances that are also enantiomers. Since many molecules in the bodies of living beings are enantiomers themselves, there is often a marked difference in the effects of two symmetrical enantiomers on living beings,"... so I guess you were right at first answer, Sublimation. Anyone help ? more explanation contrbutions here?

Thanks in advance.

Enantiomers typically have the same physical properties but different biological properties.

Physical properties: Enantiomers have the same melting points, density, solubility, etc.

Biological properties: To have a biological effect, a substance typically must fit into an appropriate receptor that has an exactly complementary shape. Just as only a right handed glove will fit a right hand, only one enantiomer in a pair of enantiomers will fit a specific receptor. The other enantiomer in the pair won't fit (e.g. a left handed glove will not fit a right hand). And, as stated above, a molecule typically must fit a receptor to have a biological effect.

Thus, two enantiomers can have the same physical properties but different biological ones.

 

[zuma35]

Enantiomers would have the same physical and chemical properties only in relation to their interactions with achiral substances. In other words, if a receptor site is achiral, it will not recognize a diff bet the enantiomers. But if the receptor site is chiral, it would possibly react with only one of the two enantiomers. Hope that's clear.

 

[Sublimation]

eeek, now I am getting really confused. When I looked into wiki/ enantiomers, it said "Enantiomers of each other often do have different chemical properties related to other substances that are also enantiomers. Since many molecules in the bodies of living beings are enantiomers themselves, there is often a marked difference in the effects of two symmetrical enantiomers on living beings,"... so I guess you were right at first answer, Sublimation. Anyone help ? more explanation contrbutions here?

Thanks in advance.

I think wat we should get from all this is taht Enantiomers differ in their spacial orientation. Or in the instance of mroe then one chiral center, the enantiomer is the non-superimposable mirror image. pretty icky stuff. Technically, they have the same physical properties, such as m.p. b.p density stability and such.

 

[zuma35]

Enantiomers are always non-superimposable mirror images of each other. That's the definition. There doesn't have to be more than one chiral center.

 

[Sublimation]

Enantiomers are always non-superimposable mirror images of each other. That's the definition. There doesn't have to be more than one chiral center.

lol sorry i meant to say in tthe instance of ONE* chiral center you will get the enantiomer, if you had more then one ud get a mixture of enantiomers and diastereomers. i was tryign to be specific, but i did a poor job of it lol. sorry guys.

 

[Dencology]

all right. after reading my Ochem book, it is clear that Enantiomers have the same physical properties such as BP, MP and solubility. but as far as chemical properties, they differ.
thanks to all of you who contributed to this post.

 

[HopefulMDclass2020]

Bump, I read in TPR 2015 that "Enantiomers have identical chemical and physical properties". I keep getting conflicting answers on the chemical properties, any consensus on this?

 

[chemtopper]

Guys, enantiomers have the same physical and chemical property but they rotate differently around polarized plane. they have the same atomes but they are bonded differently. Now for conformational isomers, everything is the same in terms of their connectivity and physical and chemical property, so why the answer to this question is A instead of D?

A Two isomers of the same molecular formula are closest in physical and chemical properties when jointly exhibiting..
A.. conformational isomerism.. B.. constitutional isomerism.. C.. geometric isomerism.. D.. enantiomeric isomerism.. E.. diastereomeric isomerism..

Both enantiomers and conformational isomers are similar in physical and chemical properties ...now pick the one which are closest in their properties ...enantiomers differ because of the optical activity ...stereo specific reactions are carried by only one enantiomer and are not shown by the others ...so best answer is conformational isomers as they differ only in their stability like staggered is more stable then eclipsed ....

 

[tommyngu]

Enantiomers have similar chemical and physical properties EXCEPT for optical activity, which is a physical property.
Each individual conformational isomer may have different physical properties, but you have to remember that conformational isomers interconvert at room temperature. Therefore, two isomers that jointly exhibit conformational isomerism are essentially the same compound since each is constantly interconverting between the different conformational isomers to form the same equilibrium.

You have to be careful with the wording of the question and answer choices. The question/answer choices are not referring to the absolute isomers, but are referring to the ability of these two isomers to exhibit a certain type of isomerism.

So... to recap:
In general, constitutional isomers interconvert at room temperature and form an equilibrium of the conformations so they are not actually different compounds.

Hope that helps!