Week 10 - Organic Chemistry II

Question 1

conformation

Answer 1

the different three-dimensional structures that can be adopted - rotation of atoms about single bonds within the same molecule

Question 2

“eclipsed” structures

Answer 2

eclipsed is not stable, it is a transition state; structures that are ‘eclipsed’ suffer from steric strain (causes electron repulsion)

Question 3

which conformation will have the lowest energy

Answer 3

the conformation where the two ‘giant CH3’ groups are furthest apart from each other

Question 4

saturated functional groups

Answer 4

halide, alcohol, ether, amine

Question 5

geometry of halides

Answer 5

tetrahedral

Question 6

geometry of alcohols + ethers

Answer 6

bent

Question 7

geometry of amines

Answer 7

trigonal pyramidal

Question 8

Halide

Answer 8

X-R when x is any halogen (F, Br, I, Cl)

Question 9

alcohol

Answer 9

OH

Question 10

Ether

Answer 10

R-O-R

Question 11

amine

Answer 11

R-N-R **nitrogens with a double bond are not amino groups

Question 12

unsaturated functional groups

Answer 12

carbonyl, aldehyde, ketone

Question 13

aldehyde

Answer 13

R-C=O
|
H

Question 14

ketone

Answer 14

R-C=O
|
R

Question 15

carboxyls: carboxylic acid, ester

Answer 15

O=C-OH, O=C-O-C

Question 16

amide

Answer 16

O=C-N-R2

Question 17

nitriles

Answer 17

N=-C (triple bond)

Question 18

skeletal isomers

Answer 18

same chemical formula, different arrangement of carbon atoms

Question 19

positional isomers

Answer 19

same chemical formula, different position of functional group

Question 20

functional isomers

Answer 20

same chemical formula, different functional groups

Question 21

cis vs trans (and E vs Z)

Answer 21

cis (E) = majority of carbon chain on same side
trans (Z) = majority of carbon chain of opposite sides

cis/trans and E/Z are not always the same though, E/Z is based on priority based on highest atomic number

Question 22

geometric isomers

Answer 22

same chemical formula, same bonding, compounds are cyclic, isomerism is at the double bond, different rotation around the bond (not mirror images)

Question 23

enantiomers

Answer 23

compounds are mirror images of each other

Question 24

chiral object

Answer 24

no plane of symmetry and must have a chiral center, all different groups only

Question 25

enantiomers differ in one physical property…

Answer 25

they are optically active

Question 26

enantiomers can be classified as…

Answer 26

dextrorotatory or levorotatory

Question 27

how to name enantiomers

Answer 27

• assign priority from 1-4 based on atomic number
• point the lowest one to the back
• draw a curved arrow to show decreasing order of priority
• R if clockwise
• S if counterclockwise

Question 28

Diastereomers

Answer 28

same chemical formula, same bonding, compounds are not mirror images of each other

Question 29

if compounds have the same molecular formula, they are…

Answer 29

isomers

Question 30

conformational isomer

Answer 30

compounds can become each other by rotating single bonds