Stereochemistry (U2,c3/6) Flashcards Preview

CfE Advanced Higher Chemistry > Stereochemistry (U2,c3/6) > Flashcards

Flashcards in Stereochemistry (U2,c3/6) Deck (16)
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1
Q

What are isomers?

A

Compounds that have the same molecular formula but differ in structural formulae

2
Q

What are geometric isomers?

A

Stereoisomers where there is a lack of rotation around one of the bonds, mostly a C=C

3
Q

What is a cis geometric isomer?

A

One in which both groups are on the same side of the C=C bond

4
Q

What is a trans geometric isomer?

A

One in which both groups are on the opposite sides of the C=C bond

5
Q

What are optical isomers?

A

Non-superimposable mirror images of asymmetric molecules - Chiral molecules or enantionmers

6
Q

What can be said about physical or chemical properties of isomers?

A

They can be very different.

7
Q

Where is optical isomerism immensely important?

A

Biological systems

8
Q

What is a racemic mixture?

A

A mixture of equimolar optical isomers (which is optically inactive)

9
Q

What effect does a racemic mixture have on the rotation of plane polarised light?

A

No effect - The rotational effect of one isomer is cancelled out by the opposite rotational effect of the other.

10
Q

What is true of structural isomers in terms of atom arrangement?

A

Their atoms are bonded together in a different order.

11
Q

What is true of stereoisomers in terms of atom arrangement?

A

The atoms are bonded in the same order, but the arrangement of the atoms in space is different for each isomer.

12
Q

What are the two kinds of stereoisomers?

A

Geometric and optical isomers.

13
Q

What kind of molecules can be geometric isomers?

A

Molecules with a C=C bond, and also saturated rings where rotation around the C-C bond is restricted.

14
Q

What do chiral compounds NOT have?

A

A centre/plane/axis of symmetry.

15
Q

Optical isomers are identical in all physical properties except… what?

A

Their effect on plane polarised light, i.e. they exhibit optical activity.

16
Q

What is the chiral centre of a molecule?

A

The central carbon atom surrounded by (usually) four DIFFERENT groups.