Organic Test 2

Front 1

naming alkyl halides: functional class

Back 1

the alkly and halide are seperate words. ex., methyl fluoride, pentyl chloride, 1-ethylbutyl bromide, cyclohexyl iodide.

Front 2

naming alkyl halides: substitutive class

Back 2

the halogen becomes a "halo-" substituent on an alkane chain. 1-fluoropentane, 2-bromopentane, 3-iodopentane, 5-chloro-2-methylpentane.

Front 3

naming alcohols: functional class

Back 3

name the alkyl group that bears the -OH and then add alcohol as a seperate word. Ethyl alocohol, 1-methylpentyl alcohol, 1,1-dimethylbutyl alcohol.

Front 4

naming alcohols: substitutive class

Back 4

identify the longest continuous chain that bears the -OH and reaplace the -e ending with -ol. Position of -OH is given by number. Ethanol, 2-hexanol, 2-methyl-2-pentanol.

Front 5

The carbon that bears the functional group is ______ hybridized in alcohols and alkyl halides.

Back 5

sp3

Front 6

reaction of alcohols with hydrogen halides

Back 6

ROH + HX ---> RX + HOH

Hydrogen halide reactivity:
HF HCl HBr HI
------------------------------>
least reactive ---> most reactive

Front 7

increasing reactivity of alcohols toward hydrogen halides

Back 7

----------------------------------------->

RCH2OH<R2CHOH<R3COH
primary < secondary < tert.
least r. most r.

Front 8

unimolecular

Back 8

only one species undergoes a chemical change

Front 9

SN1 mechanism

Back 9

has a unimolecular slow step

Front 10

increasing stability of carbocation

Back 10

------------------------------------------>
methyl<ethyl<isopropyl<t-butyl
pr. sec. ter.

Front 11

Dipole moments: alcohols and alkyl halides are _______.

Back 11

polar.

Front 12

Alcohols have a relatively high boiling point because . . . .

Back 12

they have the strongest intermolecular attractive forces. I.e., hydrogen bonding is stronger than other dipole-dipole attractions.

Front 13

things to remember about hydrogen bonds

Back 13

they are not bonds at all. OH, NH, FH. Three atoms are involved in a hydrogen bond.

Front 14

reaction of alcohols and hydrogen halides

Back 14

ROH + HX ----> RX + HOH

Front 15

Tertiary alcohol will make the stabilist carbocation because...

Back 15

because the electron donating effect of three alkyl groups (thus makes the rxn go faster)

Front 16

Generally accepted mechanism steps:

Back 16

1. protonation of alcohol F
2. loss of water to form carbocation S
3. rxn carbocation with chloride to give product F

Front 17

Step 2 (carbocation formation) of a mechanism is the slow step because:

Back 17

it has a high activation energy

Front 18

unimolecular

Back 18

a single molecule reacts in a step

Front 19

bimolecular

Back 19

two species are involved in this step

Front 20

the lewis acid - lewis base reaction

Back 20

the carbocation is a lewis acid, the chloride is the lewis base

Front 21

step 1

Back 21

protonation of alcohol

ROH + HCL + ROH2+ + Cl-

Front 22

step 2

Back 22

loss of water to form carbocation

ROH2+ = R+ + H20

Front 23

step 3

Back 23

rxn carbocation with chloride to give RCl

R+ + Cl- = RCL

Front 24

molecularity

A ----> C + D

Back 24

unimolecular

Front 25

molecularity

A + B ------> C + D

Back 25

bimolecular

Front 26

how to determine what the rds is:

Back 26

run the rxn and measure the rate of rxn, change the concentration of one reagent at a time and see if rate changes, if rxn changes that reagent is in the slow step, if rate does not change that reagent is not in the slow step.

Front 27

rate equations

Back 27

rate = k[A][B] for bimolecular
rate = k[A] for unimolecular

Front 28

SN1

Back 28

substitution nucleophilic unimolecular.

Front 29

carbocation

Back 29

a cation in which carbon shares 6 valence electrons and has a positive charge

Front 30

structure of tert-butyl cation

Back 30

positively charged carbon is sp2 hybridized. all four c's lie in the same plane.

Front 31

why do alkyl groups stabilize carbocation groups better than h's?

Back 31

electrons in c-c bonds are more polarizable than those in c-h bonds

Front 32

the more stable the carbocation, the ____________ it is formed.

Back 32

faster

Front 33

3>2>1>methyl. this effects alcohol rate by:

Back 33

3 faster than 2 faster than 1 faster than methanol

Front 34

primary carbocations are too high in E to allow SN1 mech's, then how do they form alkyl halides?

Back 34

SN2 mech's!

Front 35

Alkenes

Back 35

double bonds, olefins, CnH2n, unsaturated.

Front 36

structure of ethene:

Back 36

hch and hcc bonds are ~120 degrees, sp2 hybridized, each carbon has a half filled p orbital

Front 37

pi bond

Back 37

side by side overlap of half filled p orbitals

Front 38

constitutional isomers

Back 38

isomers with different connectivity

Front 39

stereoisomers

Back 39

same connectivity, different arrangement of atoms in space

Front 40

cis

Back 40

same side

Front 41

trans

Back 41

opposite sides

Front 42

The pi component must be broken for interconversion of stereoisomer alkenes to occur.

Back 42

***

Front 43

E:

Back 43

higher ranked substituents on OPPOSITE sides

Front 44

Z:

Back 44

higher ranked substituents on SAME sides

Front 45

E-Z: how are substituents ranked?

Back 45

they are ranked mainly in order of decreasing atomic number.

Front 46

E-Z: when two substituents are ranked the same...

Back 46

compare the atoms attached to them on the basis of their atomic numbers. I.e., -C(C,H,H) or -C(H,H,H)

Front 47

why are cis alkenes less stable than trans alkenes?

Back 47

their van der waals strain is less stable due to crowding of cis-methyl groups. Steric effect.

Front 48

cyclopropene adn cyclobutene have more angle strain than larger cyclics like cyclopentene or cyclohexene.

Back 48

*****

Front 49

cis-cycloalkenes are (more or less) stable than trans-cycloalkenes?

Back 49

more

Front 50

b elimination rxnz

Back 50

X-C-C-Y ----> C=C + X-Y

Front 51

regioselectivity

Back 51

a rxn that can proceed in more than one direction, but in which one direction predominates

Front 52

zaitsev's rule

Back 52

when elimination can occur in more than one direction, the major alkene is formed by loss of H from the b carbon having the fewest hydrogen. a rule that states that if more than one alkene can be formed during dehalogenation by an elimination reaction, the more stable alkene is the major product. In general, the compound that has a more highly substituted C=C double bond is more stable.

Front 53

dehydration of an alcohol

Back 53

ROH + H2SO4 ---> ALKENE + H2O

Front 54

rearrangements

Back 54

sometimes the alkene product of of alcohol dehydration does not have the same carbon skeleton as the starting alcohol. carbocations can rearrange.

Front 55

activation energy

Back 55

The energy required to initiate a reaction

Front 56

substitution reaction

Back 56

a functional group in a particular chemical compound is replaced by another group

Front 57

carbocation

Back 57

any cation containing an excess positive charge on one or more carbon atoms

Front 58

rate-determining step

Back 58

slowest step in a chemical reaction.

Front 59

Sn1 reaction

Back 59

substitution nucleophilic unimolecular

Front 60

SN1 reaction rate equations

Back 60

rate = k[alkyloxonium ion]

rate = k[alcohol]

Front 61

2 other ways to make alkyl halides from alcohols

Back 61

PBR3 and SOCl2

Front 62

alkenes are more stable...

Back 62

the more alkyl groupos there are on the double bond due to teh fact that alkyl groups donate small amounts to the double bonds.

Front 63

acid catalyzed dehydration of alcohols to give alkenes: acids of choice

Back 63

H2SO4 and H3PO4

Front 64

dehydrohalogenation

Back 64

alkyl halides + strong base = alkenes

Front 65

explain sp2 bonding in alkenes

Back 65

the third p orbital becomes a double bond

Front 66

E1

Back 66

occurs in the presence of a weak base or no base at all. heat.

Front 67

E2

Back 67

occurs in the presence of a strong base. heat.