Isomerism

Question 1

Structural isomer
Chain

Answer 1

Different carbon skeleton
Eg butane and methylpropane

Question 2

Structural isomer
Position

Answer 2

Same carbon skeleton but functional group is in a different position
Eg chlorobutane and 2-chlorobutane

Question 3

Structural isomer
Functional group

Answer 3

Same atoms arranged into different functional groups
Eg hexene and cyclohexane

Question 4

Stereoisomerism
Geometric

Answer 4

E/Z isomers
Different positions of substituents around a C=C
E opposite side
Z same side

Question 5

Why can geometric isomers occur?

Answer 5

Restricted movement around the C=C due to a pi bond

Question 6

Stereoisomers
Optical

Answer 6

4 different substituents around a chiral carbon
Non superimposable mirror images called enantiomers

Question 7

Optical activity
Effect on plane polarised light

Answer 7

Plane polarised light only vibrates in one direction unlike normal light
Optical isomers rotate plane polarised light
One enantiomer will rotate it clockwise and the other anti-clockwise

Question 8

What is a race mic mixture/ racemate ?

Answer 8

Contains equal amounts of both enantiomer
Cancels out each others rotating effect
Won’t show optical activity
When 2 chiral substances react there is an equal chance of making each enantiomer

Question 9

What are structural isomers?

Answer 9

Molecules with the same molecular formulas but a different structure

Question 10

What are stereoisomers?

Answer 10

Molecules with the same structural formula but a different spatial arrangement of atoms