chapter 9

Question 0

in an sn2 mechanism when does the bond breaking and forming occur?

Answer 0

the occur at the same time

Question 1

what is the difference between sn1 and SN2 reactions ?

Answer 1

the timing of the bonds breaking and forming

Question 2

the sn2 is an example of a unimolecular or bimolecular mechanism ?

Answer 2

bimolecular

Question 3

what is involved in the rate determining step of the sn2 mechanism?

Answer 3

the haloalkene and the nucleophile are both involved in the rate determining step

Question 4

does the sn2 mechanism happen via the from or back side?

Answer 4

backside attack for sn2

Question 5

how many steps are involved in sn2

Answer 5

just one step!

Question 6

describe the sn1 mechanism , when are the bonds broken and formed

Answer 6

bond breaking is completed before any bonds are formed with the nucleophile

Question 7

is sn1 unimoleular or bimolecular

Answer 7

sn1 is unimolecular

Question 8

what is involeved in the rate determining step in an sn1 mechanism

Answer 8

the haloalkane is involved in the rate determining step in an sn1 mechanism

Question 9

are there intermediates in SN2 reactions ?

Answer 9

no

Question 10

are there intermeditates in SN1 reactions?

Answer 10

yes , a carbocation intermediate is formed

Question 11

is the nucleophile involved in the kinetics of an SN1 reaction

Answer 11

no, just the haloalkene is involved in the rate mechanism

Question 12

describe the 2 things that are involved in an sn2 mechanism

Answer 12

the substrate and the nuclephile

Question 13

describe the stereochemistry of the sn1 mechanism

Answer 13

a racemic mixture is formed

Question 14

describe the stereochemistry of an sn2 mechanism

Answer 14

there is an inversion of configuration

Question 15

the stability of carbocations in SN1 reactions are examples of what kind of factors

Answer 15

electronic factors

Question 16

SN2 reactions are governed by what kind of factors

Answer 16

steric factros

Question 17

in an SN1 reaction is a 3 or 1 more stable

Answer 17

a 3 is more stable

Question 18

an allylic or benzellic carbocation is more stable in sn1 or SN2 reactions

Answer 18

sn1

Question 19

describe what an allylic carbon looks like

Answer 19

it has a double bond next to the carbocation

Question 20

what makes a benzylic carbocation so stable

Answer 20

its ability to make resonance structures

Question 21

in SN2 reactions are we more likely to see 1 or 3 carbocations

Answer 21

1 , because we dont want steric hinderance in SN2 reactions

Question 22

describe what beta branching is

Answer 22

these are branches that are coming off of the central carbon

Question 23

the less beta branches that something has … the …the reaction

Answer 23

the less beta branches the faster the reaction

Question 24

what is the charge like on sn1 and SN2 reaction leaving groups

Answer 24

there is a partial negative charge on the leaving group in both sn1 and SN2 reactions

Question 25

what makes the best kind of leaving group?

Answer 25

the best leaving groups are those that are weak bases (of strong acids )

Question 26

weak bases are very stable or unstable antions?

Answer 26

weak bases make stable anions

Question 27

which is a better leaving group i or f

Answer 27

i

Question 28

which is a better leaving group br or cl

Answer 28

br

Question 29

what is the role of the solvent ?

Answer 29

it dissolves the reactant

Question 30

what are the 2 kinds of solvents

Answer 30

protic and aprotic

Question 31

what is something that we can use to determine is polar or non polar

Answer 31

we can use the dielectric constant to determine if something is polar or non polar

Question 32

if the dielectric constant of a solvent is 15 what kind of solvent is it

Answer 32

polar

Question 33

if the dielectric constant of a solvent is 5 or less what kind of solvent is it

Answer 33

non polar

Question 34

list the 3 kinds of POLAR PROTIC SOLVENTS YOU SHOULD KNOW

Answer 34

alcohols water formic acid

Question 35

dmso is what kind of solvent

Answer 35

aprotic

Question 36

acetone is what kind of solvent

Answer 36

aprotic

Question 37

what does the rate of an SN1 reaction depend on

Answer 37

the rate of an sn1 raction depends on the ability of a solvent to keep opposite charges separated and the ability to stabilize the charge

Question 38

what kind of solvents work best of SN1 reactions

Answer 38

polar protic solvents

Question 39

what kind of solvents work best for SN2 reactions

Answer 39

polar aprotic solvents

Question 40

what is nucleophilicity

Answer 40

it measures the rate at which it displaces a leaving group from a haloalkane

Question 41

nucleophiles are similar to what kind of bases

Answer 41

bronstead lawry bases

Question 42

why are nucleophiles and bronstead lawry bases similar

Answer 42

because they both deal with a lone pair of electrons

Question 43

what kind of base makes a good nucleophile

Answer 43

a strong base

Question 44

if something has a pka above 11 what kind of nucleophile is it

Answer 44

a pka above 11 means that it is a strong nucleophile

Question 45

if something has a pka below 11 what kind of nucleophile is it?

Answer 45

that means that it is a weak nucleophile

Question 46

in an aprotic solvent which is more nucleophilic f or i

Answer 46

f

Question 47

in a polar protic solvent which is more nucleophilic f or i

Answer 47

i

Question 48

which is more polarizible f or i

Answer 48

i is most polarizabile

Question 49

what do SN2 reactions have to worry about

Answer 49

steric hinderances

Question 50

in which ways are nucleophiles and bases similar

Answer 50

they both accept protons

Question 51

what is beta elimination

Answer 51

taking a proton away to break a bond to get a more stable molecule

Question 52

what kind of bases are needed for beta elimination

Answer 52

strong bases

Question 53

describe the zaitsev rule

Answer 53

the more substituted alkene is the dominant product, highlighter rule

Question 54

how do we do elimination ?

Answer 54

we look at the beta carbons and use beta hydrogens to determine where the double bond will be , also rememeber that the leaving group comes off !

Question 55

what are the 2 mechanisms of beta elimination

Answer 55

e1 and e2

Question 56

what is the difference between e1 and e2

Answer 56

the timing and breaking of the bonds

Question 57

describe the bond breaking etc of an e2 mechanism

Answer 57

the carbon and leaving group break to give the carbocaiton , before the reaction occurs . this means that it is a 2 step process

Question 58

is e1 bimolecular or unimolecular

Answer 58

it is unimolecular

Question 59

what is the rate determining step in an e1 mechanism

Answer 59

the haloalkane

Question 60

how many transition states are there in an e1 mechanism

Answer 60

there are 2 transition states

Question 61

t/f e1 and sn1 are always competing

Answer 61

true

Question 62

is the e2 mechanism a concerted process

Answer 62

yes

Question 63

what order are e1 reactions

Answer 63

they are 1st order

Question 64

what order are e2 reactions

Answer 64

they are 2nd order reactions

Question 65

is there rearrangement in e1 reactions

Answer 65

yes

Question 66

does e1 follow zaitsevs rule

Answer 66

yes

Question 67

if there is a fatty base what mechanism does it follow

Answer 67

e2

Question 68

if there is a fatty base is zaitsevs rule followed

Answer 68

no

Question 69

in which reaction must something be anti and coplanar

Answer 69

in e2 reactions