Chapter #4

Question 1

an acid and base reaction will continue to occur as long as ______

Answer 1

the reactants are more reactive than the products (or the reverse reaction will begin to occur)

Question 2

a lewis acid is an electron _____

Answer 2

acceptor

Question 3

a lewis base is an electron ______

Answer 3

donor

Question 4

lewis bases tend to be _____

Answer 4

nucleophiles

Question 5

lewis acids tend to be ____

Answer 5

electrophiles

Question 6

coordinate covalent bonds

Answer 6

covalent bonds in which both electrons in the bond came from the same starting material

Question 7

In the Bronsted lowry definition, an acid is a species that can ______ while a base is a species that can ____

Answer 7

donate a proton

accept a proton

Question 8

amphoteric

Answer 8

can act as acid or base

Question 9

what does Ka measure?

Answer 9

the strength of an acid in a solution.

Question 10

acids with a Pka value below ____ are considered strong acids

Answer 10

-2

Question 11

the ____ the Ka and the ___ the pKa means a stronger acid

Answer 11

higher

lower

Question 12

Discuss acidity and periodic table trends and acidity and EN trends

Answer 12

the more EN the atom, the better the acid (can pop off the H easier)
further down in the periodic table, bond strength weakens so you can also pop off the hydrogen easier

Question 13

which types of hydrogens are specifically acidic pertaining to a carbonyl?

Answer 13

alpha hydrogens

Question 14

name some important biological amphoteric molecules

Answer 14

water, amino acids, and bicarbonate

Question 15

compare nucleophilicity and basicity

Answer 15

nucleophile strength is based on relative rates of reaction with a common electrophile (kinetic property), while base strength is related to the equilibrium position of a reaction (thermodynamic property)

Question 16

what are the 4 factors that determine nucleophilicity?

Answer 16

charge
electronegativity
steric hindrance
solvent

Question 17

how does nucleophilicity depend on charge?

Answer 17

nucleophilicity increases with increasing electron density (more negative charge)

Question 18

how does nucleophilicity depend on electronegativity?

Answer 18

nucleophilicity decreases as EN increases because these atoms are less likely to share electron density

Question 19

how does nucleophilicity depend on steric hindrance?

Answer 19

bulkier molecules are less nucleophilic

Question 20

how does nucleophilicity depend on the solvent?

Answer 20

protic solvents can hinder nucleophilicity by protonating the nucleophile or through hydrogen bonding

Question 21

in polar protic solvents, nucleophilicity increases ____ the periodic table, while in polar aprotic solvents, nucleophilicity increases _______ the periodic table

Answer 21

down
up

protons in solution of protic solvent are attracted to the nucleophile.

Question 22

if a solvent is not given on test day, assume it is a ____ solvent

Answer 22

polar solvent (protic or aprotic)

Question 23

in____ solvents, nucleophilicity relates directly to basicity

Answer 23

aprotic

Question 24

nucleophiles

Answer 24

have either lone pairs or pi bonds that can form new bonds to electrophiles

Question 25

electrophiles

Answer 25

positive charge or positively polarized atom that accepts an electron pair when forming new bonds with a nucleophile

Question 26

what affects electrophilicity

Answer 26

the more positive, the more electrophilic better leaving group, better electrophilicity empty orbitals, better electrophilicity

Question 27

describe the electrophilicity of carboxylic acid derivitives

Answer 27

anhydrides > carboxylic acids = esters > amides

Question 28

for carboxylic acid derivatives: derivatives of higher reactivity can form derivatives of ____ reactivity but not vice versa

Answer 28

lower

Question 29

heterolytic reactions

Answer 29

the opposite of coordinate covalent bond formation: a bond is broken and both electrons are given to one of the two products

Question 30

the best leaving groups are those that are able to _____

Answer 30

stabilize the extra electrons | have resonance or EWG

Question 31

___ bases make good leaving groups

Answer 31

weak bases, stable

Question 32

SN1 reactions

Answer 32

2 steps first step is the rate limiting step in which the LG leaves then the nucleophile attacks the carbocation first order reaction that only depends on the concentration of the substrate

Question 33

which step of SN1 reactions is the rate limiting step?

Answer 33

first step, LG leaves

Question 34

SN1 reactions are ____ order reactions

Answer 34

first

Question 35

the product of SN1 reaction is ____ because the formation of the carbocation intermediate causes the reaction to pass through a planar intermediate

Answer 35

a racemic mixture | the nucleophile can attack from either side

Question 36

what is another name for SN1 reactions

Answer 36

unimolecular nucleophilic substitution reaction

Question 37

what is another name for SN2 reactions

Answer 37

bimolecular nucleophilic substitution reaction

Question 38

SN2 reactions

Answer 38

one step the nucleophile attacks the compound at the same time the leaving group leaves rate limiting step involves 2 molecules (nucleophile and substrate). backside attack nucleophile must be strong and the electrophile cannot be too sterically hindered.

Question 39

a concerted reaction is one that ____

Answer 39

only has one step

Question 40

discuss rate of SN1 and SN2 reactions based on how substituted the central carbon is

Answer 40

more substituted: faster SN1 | less substituted: faster SN2

Question 41

what increases electrophilicity?

Answer 41

better leaving group and positive charge

Question 42

the conjugate bases of strong acids are __ bases

Answer 42

weak

Question 43

the molecules with ____ steric hindrance will be the better nucleophile

Answer 43

least

Question 44

oxidation state is an indicator of the hypothetical charge that an atom would have if all bonds were completely _____

Answer 44

ionic

Question 45

oxidation is an _____ in oxidation state and a ____ in electron

Answer 45

increase in oxidation state loss of electrons more bonds to heteroatoms (besides carbon and hydrogen)

Question 46

reduction is a ____ in oxidation state or a ____ in electrons

Answer 46

decrease gain increasing the number of bonds to hydrogen

Question 47

compare oxidation and reduction in terms of bonds

Answer 47

oxidation is increasing bonds to heteroatoms (not oxygen and hydrogen) reduction is increasing bonds to hydrogen

Question 48

what is an example of the most oxidized compound?

Answer 48

carbon dioxide

Question 49

oxidizing agents usually have a lot of ____

Answer 49

oxygens (and high affinity for electrons)

Question 50

reducing agents usually have a lot of ___

Answer 50

hydrogens (and low affinity for electrons)

Question 51

why are transition metals often included in oxidation or reducing agents?

Answer 51

low ionization energies and presence of d-orbitals allow them to give up and accept electrons easily.

Question 52

the ____ oxidized the functional group, the more reactive it is in both nucleophile-electrophile and oxidation-reduction reactions.

Answer 52

more this is because the more oxidizing groups, the more electronegative groups around it and the larger partial positive charge it will experience

Question 53

compare reactivity of aldehydes and ketones

Answer 53

aldehydes are usually more reactive toward nucleophiles because they have less steric hindrance.

Question 54

In SN2 reactions, _____ carbons will not react

Answer 54

tertiary

Question 55

aldehyde + diol ==>

Answer 55

acetal

Question 56

aldehyde + 2 equivalents of alcohol ==>

Answer 56

acetal

Question 57

ketone + diol ==>

Answer 57

ketal

Question 58

ketone + 2 equivalents of alcohol ==>

Answer 58

ketal

Question 59

stereoselectivity vs. stereospecificity

Answer 59

stereoselectivity: when one configuration of the product is more readily formed due to product characteristics stereospecificity: the configuration of the reactant necessarily leads to a specific configuration in the product.

Question 60

are amino groups or alcohol groups more nucleophilic?

Answer 60

amino groups

Question 61

Is OH- or RO- a better nucleophile?

Answer 61

ROH- because the alkyl group donated additional electron density.

Question 62

is HF a strong acid?

Answer 62

no

Question 63

can carboxylic acids, ketones, or tertiary alcohols undergo oxidation?

Answer 63

no, they already have 4 bonds to other carbons or oxygens already

Question 64

what is the hierarchy of reactivity for carboxylic acids that dictates how reactive they are toward nucleophilic attack?

Answer 64

anhydride > carboxylic acid and ester > amide derivatives of higher reactivity can form derivatives of lower reactivity but not vice versa/