Orgo Exam 2

Question 1

same connectivity, but different in terms of geometry

Answer 1

stereoisomer

Question 2

different compound with same connectivity but not mirror images

Answer 2

diastereomers

Question 3

physical properties of diastereomers

Answer 3

have different physical properties

Question 4

non-superimposable mirror image

Answer 4

enantiomer

Question 5

physical properties of enantiomers

Answer 5

they have the same properties except they rotate polarized light in opposite directions

Question 6

cant interconvert, must have 4 different groups

Answer 6

chiral atoms

Question 7

clockwise

Answer 7

R

Question 8

counterclockwise

Answer 8

S

Question 9

are neutral amines chiral?

Answer 9

if amines are trapped in a ring structure, they are chiral

Question 10

are conformational isomers chiral?

Answer 10

most aren’t but a few are. If it can inner convert easily, it is not chiral

Question 11

restricted rotation around a single bond

Answer 11

atropisomer

Question 12

max number of possible enantiomers

Answer 12

2^n where n is the number of chiral centers

Question 13

achiral compounds with chiral centers

Answer 13

meso compounds

Question 14

two ways to distinguish enantiomers

Answer 14

1. chiral interactions (analogous to hand in glove)

2. rotation of plane polarized light

Question 15

a 50/50 mixture of enantiomers

Answer 15

racemic

Question 16

bronsted acid

Answer 16

proton donor

Question 17

bronsted base

Answer 17

proton acceptor

Question 18

high pka, — acidic

Answer 18

less

Question 19

which side does an acid/base reaction favor?

Answer 19

going to favor side with weaker acid/ side with most stable conjugate base

Question 20

lewis acid

Answer 20

electron pair acceptor

Question 21

lewis base

Answer 21

electron pair donor

Question 22

electrophile

Answer 22

lewis acid

Question 23

nucleophile

Answer 23

lewis base

Question 24

tries to form a bond with something other than hydrogen

Answer 24

nucleophile

Question 25

when forward and reverse reaction rates are equal

Answer 25

equilibrium

Question 26

How much energy is required to make a system do something

Answer 26

changeGprime --- gibbs free energy

Question 27

as k increases, change G ---

Answer 27

decreases

Question 28

-changeG favors

Answer 28

products

Question 29

energy of forming or braking bonds

Answer 29

enthalpy- changeH

Question 30

entropy

Answer 30

changeS

Question 31

-changeH favors --- changeG | is this exothermic or endothermic?

Answer 31

- | exothermic

Question 32

+change favors ---changeG | exo or endo?

Answer 32

+ | endothermic

Question 33

+changeS favors ---changeG

Answer 33

-

Question 34

-changeS favors --- changeG

Answer 34

+

Question 35

--- take priority over halide for determining main chain

Answer 35

alcohols

Question 36

number through alkenes must have the --- number

Answer 36

lowest

Question 37

main chain contains groups that are facing the same direction

Answer 37

cis isomer

Question 38

main chain contains groups that are facing opposite directions

Answer 38

trans isomers

Question 39

E

Answer 39

trans

Question 40

Z

Answer 40

cis

Question 41

atropisomers are only chiral when...

Answer 41

the rotation barrier is high enough (cant rotate all the way around)

Question 42

kcal to rotate around a single bond

Answer 42

6

Question 43

kcal to rotate around a double bond

Answer 43

35

Question 44

kcal to rotate atropisomer

Answer 44

greater than 20

Question 45

enzymes --- activation energy

Answer 45

lower

Question 46

which has a higher melting point E or Z?

Answer 46

Z

Question 47

--- are in trans fat (they are more easily stacked)

Answer 47

Z

Question 48

the side of the reaction with the --- enthalpy will be the most stable

Answer 48

highest

Question 49

the --- curve is the rate limiting one

Answer 49

highest

Question 50

reactive intermediate

Answer 50

carbocation

Question 51

why are some carbocations more stable than others?

Answer 51

hyperconjugation

Question 52

hyperconjugation --- bonds

Answer 52

stabilizes

Question 53

hyperconjugation is when ---

Answer 53

alkyl groups contribute a negative charge (just share, don't actually donate)

Question 54

regioselective

Answer 54

reaction goes to a certain region, will form the most stable isomer

Question 55

lowers activation energy

Answer 55

catalyst

Question 56

a catalyst usually introduces a ---

Answer 56

intermediate

Question 57

the more acidic molecule has the --- stable base

Answer 57

most

Question 58

delocalizes a negative charge

Answer 58

resonance

Question 59

equilibrium will favor whichever side has the ---

Answer 59

more stable negative charge ( conj base)

Question 60

different positions that a molecule can twist

Answer 60

conformations

Question 61

a matter of R or S

Answer 61

configuration

Question 62

cis/trans isomers are

Answer 62

diastereomers

Question 63

compounds that have stereocenters but also has symmetry making it the mirror image of itself

Answer 63

a meso compound

Question 64

a compound is chiral if it is : (2)

Answer 64

they have stereocenters and are not meso compounds

Question 65

chiral compounds rotate polarized light, if the rotation is clockwise then we say it is ---, if it is counterclockwise, we say it is ---

Answer 65

+ | -

Question 66

when will no light be rotated?

Answer 66

if we have a 50/50 mixture of enantiomers (racemic)---because the rotations cancel each other out

Question 67

S/R and +/- are or are not related?

Answer 67

are not

Question 68

whether or not a compound is + or - often depends on

Answer 68

temperature