Biomolecular Bonding:

Question 1

What are the main types of isomerism?

Answer 1

• Structural Isomer

- Stereoisomer

Question 2

What are the type of stereoisomers?

Answer 2

• E/Z isomerism

- Optical isomerism

Question 3

What are the types of structural isomers?

Answer 3

• Chain isomer
• Functional group isomer
• Position isomer

Question 4

Why is the way that atoms are joined together important?

Answer 4

Arranging it in any other way could affect whether it is still the same molecule

Question 5

What could give rise to a number of structural isomers?

Answer 5

Particular atoms being rearranged in different molecular arrangements

Question 6

Why are structural isomers likely to have different chemical properties?

Answer 6

The functional groups contained may be in a different order and so will exhibit different interactions and reactivity

Question 7

What is similar and what is different between structural isomers?

Answer 7

• Same composition/molecular formula

- Different order in which atoms are bonded together

Question 8

What are stereoisomers?

Answer 8

Molecules with the same composition/molecular formula and order of bonding of particular atoms but different three-dimensional arrangement in space

Question 9

What are optical isomers?

Answer 9

Compounds with the same molecular formula and order of bonding between particular atoms, but non-superimposable mirror images of each other (an enantiomers pair)

Question 10

How are some analytical techniques used to find out what proportion of different enantiomers are present?

Answer 10

Using the fact that optical isomers have equal and opposite optical activity

Question 11

What does it mean that a substance in enantiopure?

Answer 11

Contains only one enantiomer

Question 12

What is a race mate?

Answer 12

A substance containing an equal proportion of each enantiomer

Question 13

What is the optical activity of enantiomers?

Answer 13

The direction that enantiomers rotate plane-polarised light

Question 14

When is it useful and mot useful to label molecules using the empirically derived (much older) system?

Answer 14

Useful when interested in practically differentiating enantiomers, but not useful for defining stereochemical arrangements for molecules where we don’t know their properties

Question 15

List the symbols that the empirically derived system uses:

Answer 15

(+)- or (-)-

d- or l- (both lower case)

Question 16

What does it mean that enantiomers of a compound will have an equal and opposite optical activity?

Answer 16

Each enantiomer will rotate Plane polarised light by the same degree but in different directions

Question 17

Why is stereochemistry important when understanding molecules?

Answer 17

Molecules behave in specific ways depending on their stereochemistry

Question 18

What is a stereocentre?

Answer 18

A geometric point in space