Exam 2

Question 1

Enantiomers

Answer 1

Mirror images

Question 2

Configurational aka …

Answer 2

Steroisomers
Differ in the 3D position of the groups

Question 3

Chiral

Answer 3

Not identical to its mirror image

Question 4

Achiral

Answer 4

superimposable on its mirror image

Question 5

Chirality center

Answer 5

Carbon bonded to 4 different groups

Question 6

Optical rotation

Answer 6

Chiral compound that can rotate plane- polarizing light

Question 7

Clockwise light rotation

Answer 7

Dextrorotatory (D)
Positive +

Question 8

Counterclockwise

Answer 8

Levorotatory (L)
Negative -

Question 9

Racemic Mixtures

Answer 9

Mixtures containing equal quantities of enantiomers, optically inactive

Question 10

Homochiral/Enantiopure

Answer 10

All the molecules in a mixture of the same handedness (same direction of light rotation)

Question 11

Enantiomeric Excess

Answer 11

Mixture of enantiomers where one isomer is present in larger amounts

Question 12

R

Answer 12

Clockwise

Question 13

S

Answer 13

Counterclockwise

Question 14

How do enantiomers differ?

Answer 14

In their interactions with chiral molecules or phenomena

Question 15

Diastereomers

Answer 15

Sterioisomers that are not mirror images

Question 16

Fischer projections

Answer 16

Horizontal- pointed out
Vertical- pointed back

Question 17

Meso compound

Answer 17

A compound with at least two chirality centers that is achiral

Question 18

Why are meso compounds achiral?

Answer 18

they are superimposable on its mirror image

Question 19

Why do alcohols have such high boiling points?

Answer 19

Hydrogen bonding

Question 20

Alcohols and alkyl halides are (polar/nonpolar)

Answer 20

Polar

Question 21

What increases the boiling point of halogens?

Answer 21

Polarizability

Question 22

What is the reactivity trend of halides

Answer 22

HI>HBr>HCl>HF

Question 23

Reactivity trend of alcohols

Answer 23

Primary<secondary<tertiary

Question 24

The peaks are called:
The valleys are called:

Answer 24

Transition states
Intermediate

Question 25

What are the Steps of the SN1 Mechanism
What is the rate determining step?

Answer 25

Protonate the alcohol
Create the carbocation
Attack the carbocation

The formation of the carbocation (unimolecular)

Question 26

What do you need to watch for in secondary carbocations?
Why does this happen?

Answer 26

Inversion of configuration
Methyl shift or hydride shift
To achieve stability

Question 27

What do you need to watch for with tertiary carbocations?
Produce…

Answer 27

Scrambling
a racemic mixture

Question 28

What are the steps of SN2 reactions?
What is the slow step?

Answer 28

1. protonation of the alcohol
2. loss of water and bonding of the halide

Step 2 (bimolecular)

Question 29

What are the 3 ways of making an alkyl halide?

Answer 29

1. Alcohol + thionyl chloride
2. Alcohol+ PBr3 or PCl3
3. Alcohol + Br or Cl

Question 30

What carbo cations are used in SN1?
SN2?

Answer 30

Tertiary and secondary
Primary

Question 31

How does SN2 occur?

Answer 31

Inversion of configuration, and backside attack by the nucleophile

Question 32

Steric Hinderance

Answer 32

the space occupied by the alkyl group, the more of this the slower the reaction

Question 33

what make good leaving groups?

Answer 33

Sulfurs and H20
RF<RCl<RBr<RI
The more negative the better

Question 34

Steps of Solvolysis
What is the rate determining

Answer 34

1. Loss of leaving group
2. Attack of weak nucleophile
3. Loss of proton

Step 1

Question 35

Solvolysis is what kind of reaction mechanism? why?

Answer 35

SN1, a carbocation is formed

Question 36

How do you get a 50/50 mixture, how do you get an unequal one?

Answer 36

Leaving group completely out of the way
Leaving group hovering