Final CHM 255

Question 1

lab 5

EAS/ electrophilic aromatic substituion

Answer 1

ring acts as a nucleophile to attack eletrophilic groups

ex: halogenation, alkylation, acylation, etc.

Question 2

lab 5

activating groups

Answer 2

electron donating groups

direct ortho para

Question 3

lab 5

deactivating groups

Answer 3

electron with drawing substituents

meta directors except for halogens

Question 4

lab 5

what is the mechanism for EAS?

Answer 4

1. nuc attack by ring on electrophile
   (resonance by C+)
2. pt to restore aromaticitiy

Question 5

lab 5

can F participate in halogenation of a ring via EAS?

Answer 5

no, it is too strong and too reactive

Question 6

lab 5

Why is nitration so useful?

Answer 6

bc when you reduce the nitro group to amine you can then react that amine in many different ways

Question 7

lab 6

Triglycerides

Answer 7

Three fatty acid chains attatched to a glycerol molecule

fatty acids can be saturated or unsaturated

Question 8

lab 6

Phospholipids

Answer 8

fatty acid chain and glycerol component + polar head group

Question 9

lab 6

Which part of phospholipids is hydrophobic and which part is hydrophilic?

Answer 9

the head is hydrophilic and the tails are hydrophobic

think of the lipid bilayer

Question 10

lab 6

Prostaglandins

Answer 10

carboxlyic acid + long tail of C-H bonds and a 5 membered ring

Question 11

lab 6

Terpenes

Answer 11

conjugated double bond chains that absorb light well

Question 12

lab 6

steroids

Answer 12

derived from terpenes, hormones etc.

Question 13

lab 6

unsaturated fatty acids

Answer 13

at least one pi C=C bond, liquids at room temp

Question 14

lab 6

saturated fatty acids

Answer 14

no double bonds in the chain, typically solids at room temperature

Question 15

lab 6

Mechanism for base catalyzed hydrolysis of esters

Answer 15

• nuc attack
• LLG
• pt
• pt

Question 16

lab 6

What is the product when an alkene is treated with KnMO4?

Answer 16

oxidative cleavage, two ketones or two aldehydes etc.

Question 17

lab 7

enols

Answer 17

over all neutral molecules that tautomerize with ketones

mildly nucleophilic, not as much as enolates

Question 18

lab 7

enolates

Answer 18

fully negativley charged molecules that are very nucleophilic

Question 19

lab 7

perkin condensation

Answer 19

aromatic aldehyde + derivative of acetic acid = alpha beta, unsaturated carboxylic acid

a sort of aldol condensation

Question 20

lab 7

Iodoform test

Answer 20

used to characterize methyl ketones bc when a ketone is treated with I2 under basic conditions a CI3 group is formed + a carb acid and the CI3 is a yellow crystalline solid

Question 21

lab 7

Aldol condensation

Answer 21

aldol addition products heated in basic conditiosn to yield loss of water and a pi bond

Question 22

lab 7

Mechanism for alpha halogenation under basic condtions

Answer 22

1. formation of X3 intermediate
2. nuc attack by NaOH
3. LLG
4. pt

X added until all alpha protons are gone at the least substitued C

Question 23

lab 7

Mechanism for alpha halogenation under acidic conditions

Answer 23

1. formation of enol
2. nuc attack by enol on X2
3. pt

one X added to the more substitued postion

Question 24

lab 7

The more acidic you make something the — soluble it will be in water

Answer 24

less

Question 25

# chpt 7 what is the difference between washing and extracting?

Answer 25

washing = keeping aq layer extracting = keeping org layer

Question 26

# lab 8 ATP

Answer 26

fuel of cells, can be used to drive systems out of equilibrium

Question 27

# lab 8 catenane molecular motors

Answer 27

two interlocked rings where one ring travels clock wise around the other based on the charges present (or rather not present on the ring)

Question 28

# lab 8 explain transient methylation of carboxlylates

Answer 28

the carboxylate is methylated by the sulfur molecule - treatment with NaOH returns methyl to sulfur molecule and yields the carboxylate again

Question 29

# lab 8 carb acids treated with a carbodiiamides

Answer 29

anhydride

Question 30

# lab 8 What is the driving force behind non biological fuel reactions?

Answer 30

the formation of a temporary bond

Question 31

# lab 8 Charged things are --- soluble in water

Answer 31

more | bc of the polarity of water

Question 32

# lab 8 The --- fuel added the longer the rate of reaction for non biological fuel systems | opposite of our actual findings

Answer 32

less | idk why tho

Question 33

# lab 8 Are non biological fuel systems in equilibrium?

Answer 33

No!

Question 34

# Mass spec EI ionization

Answer 34

Molecule is hit with electrons which causes it to lose one and generate a radical that can under go fragmenation | fragmentation detected by mass spec

Question 35

# mass spec M+ 1 peak

Answer 35

affected by N,O,Si and S - mass of M+ peak +1

Question 36

# mass spec M +2 peak

Answer 36

affected by Br, Cl and Sulfur - peak + from M+ peak that indicates the presence of one of the above atoms isotopes

Question 37

# mass spec Base peak

Answer 37

Most intense peak in the spectrum | based on intensity

Question 38

# mass spec Sigma bond dissociation

Answer 38

indicates no lp or pi bonds in molecule to start fragmentation

Question 39

# mass spec Homolytic alpha bond cleavage

Answer 39

the two electrons of a bond go to same places, splitting a bond one bond away from the atom bearing the radical cation | two headed arrow

Question 40

# mass spec Heterolytic alpha cleavage

Answer 40

both e are going to same place, one atom away from the atom bearing the radical cation | two headed arrows

Question 41

# mass spec If a sample has NO N what can be said about finding its M+ peak?

Answer 41

it cannot be an odd M/z

Question 42

# mass spec Only --- species are detected by mass spec

Answer 42

charged species