Lecture 8- Stereochemistry 1/4

Question 1

Draw the family tree of isomers

Answer 1

Question 2

definition of a structural isomer

Answer 2

different compounds with the same molecular formula (but a different structural formula).

Question 3

Draw two structural isomers with the molecular formular C4H10

Answer 3

Question 4

What is a stereoisomer?

Answer 4

Same constitutions, same formula, different spatial arrangement.

Question 5

What is a conformational isomer?

Answer 5

Different arrangement of atoms due to bond rotation

Question 6

What bonds allow for conformational isomers?

Answer 6

sigma bonds

Question 7

Draw the two types of confirmation of ethane using the Newman projection. Name them

Answer 7

Question 8

Is the staggered or eclipsed confirmation preferred?

Answer 8

Staggered because it is in a lower energy due to the C-H bonds being further from each other- minimises repulsion between electrons.

Question 9

Draw a chair cyclohexane showing the equatorial and axial bonds

Answer 9

Question 10

An axial bond is drawn upwards for every carbon that points …….. and downwards for every carbon that points ………….

Answer 10

up
down

Question 11

How do you draw equatorial bonds?

Answer 11

109.5 degrees from the axial bonds. If axial bond is up, equatorial is down and vice versa.

Question 12

Draw ring flipping for this molecule.

Answer 12

Question 13

In terms of ring flipping, is it preferred for groups of higher molecular mass to be in axial positions or equatorial?

Answer 13

Equatorial. Axial is higher in energy- groups in axial are closer together.