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A-Level Chemistry // Organic > Stereoisomers > Flashcards

Flashcards in Stereoisomers Deck (14):
1

Stereoisomers

Same structural formula but a different arrangement in space/ same group

2

What can't happen in stereoisomers

Rotation of double bonds

3

Why can't double bonds rotate

Carbon atoms in a c=c double bonds and the atoms bonded to these carbons all lie in the same plane (they're planar).

C=C double bonds can't rotate around them like they can around single bond. Double bonds are fairly rigid.

4

What does the restricted rotation around the c=c cause

A type of stereoisomers called E/Z rotation.

5

What is optical isomers

Different arrangements of the 4 different groups about a central c atom in a molecule -> non-identical mirror images.

6

Optical isomers are identical in every respect except

1. They rotate plane polarised light in opposite directions.
2. One may be biologically active, the other not.

7

What happens if we have a 50:50 mixture of optical isomers

It's called a racemic mixture and its optically inactive because it cancels each other out.

8

What is each isomer called

Enantiomer

9

What does each enantiomer have

The same chemical and physical properties as each other but interact differently with polarised light

10

polarimetry

If you have a racemic mixture the overall affect

If you have a racemic mixture, the overall affect doesn't change. It stays straight

11

"No effect on plane polarised light". How correct is this statement

It's wrong because there is an affect but half goes to right half goes to left so it cancels each other out due to it being a racemic mixture.

12

Explain which property of butan-2-ol allows it to have optical isomers

The 2nd carbon is the critical centre that have 4 different groups

13

What is a parent functional group

OH

14

Which part allows for optical isomerism

Critical centre