Identical or Enantiomers Chemistry help please

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Leah.J
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I don't understand why the ones in A are identical and the ones in C aren't , I know that B are enantiomers because they're non-superimposable mirror images of each other but I don't know how to determine what A an C are
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MindMax2000
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Rotate the second compound in A 120 degrees anticlockwise. Should be identical.
Rotate the second compound in C 120 degrees clockwise. Should see an enantiomer.
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Mattp9850
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If you're struggling to make sense of it, take a piece of a4 paper and roll it up to make a straw, repeat for a second piece. Twist one straw around the centre of the other and label the ends or colour code them to represent each molecule. You'll see as you rotate A in 3D space they're identical, it's just been rotated so the OH is facing away from you.
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Leah.J
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(Original post by Mattp9850)
If you're struggling to make sense of it, take a piece of a4 paper and roll it up to make a straw, repeat for a second piece. Twist one straw around the centre of the other and label the ends or colour code them to represent each molecule. You'll see as you rotate A in 3D space they're identical, it's just been rotated so the OH is facing away from you.
can I ask another question ?
Its a stupid one but I don't know how to decide whether an alkene has a chiral center or not, Why isn't the C on the left here considered a chiral center ?Name:  Screen Shot 2020-05-07 at 4.05.47 PM.png
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does it have to have 4 different groups attached to the double bond for their to be a chiral center ?

I'm sorry about the quality of the picture
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Mattp9850
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Of course, no problem.

Yeah it has to has to be 4 different groups, as a general rule all alkenes are non-chiral with the exception of allenes.

They can still be stereoisomers though as they can't rotate about the double bond (with the exception of high temperature systems) and can't be superimposed.

I hope that makes sense!
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Mattp9850
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An alkene can be a group of a chiral carbon though! But the carbon in the double bond can't be.
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Leah.J
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(Original post by Mattp9850)
An alkene can be a group of a chiral carbon though! But the carbon in the double bond can't be.
Got it, one last thing please,
would the correct answer be C triple bond N here ?Name:  Screen Shot 2020-05-07 at 6.18.01 PM.png
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Mattp9850
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(Original post by Leah.J)
Got it, one last thing please,
would the correct answer be C triple bond N here ?Name:  Screen Shot 2020-05-07 at 6.18.01 PM.png
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Yeah, it should be.

Do you have the full list of priorities of functional groups? The master organic chemistry website has a comprehensive list if you need it.
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Leah.J
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u

(Original post by Mattp9850)
Yeah, it should be.

Do you have the full list of priorities of functional groups? The master organic chemistry website has a comprehensive list if you need it.
Alright thank youuu
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