Week 10-11

Question 1

It is sometimes called olefin

Answer 1

Alkene

Question 2

Alkene is sometimes called

Answer 2

Olefin

Question 3

An alkene, sometimes called an olefin, is a hydrocarbon that contains a

Answer 3

Carbon-carbon double bond

Question 4

General formula of alkene

Answer 4

CnH2n

Question 5

The double bonds in alkenes are higher in ____ than single bonds and are more_____

Answer 5

energy; reactive

Question 6

It is the smallest, simplest alkene

Answer 6

Ethene

Question 7

Ethene is a_____ and the angle between its bonds is approximately _____

Answer 7

planar; 120°

Question 8

The ___ bonds are ______ stronger in ____than in ethane because the ___ bond draws electron density away from the carbon, which draws electron density away from the hydrogens

Answer 8

C-H
Stronger
Ethene
Pi

Question 9

It is an orange pigment and vitamin A precursor

Answer 9

β-Carotene

Question 10

(True or False)
Cycloalkenes are named similarly, but because there is no chain end to begin from, we number the cycloalkene so that the double bond is between C3 and C4

Answer 10

False
(C1 and C2)

Question 11

The ______ substituent has as low a number as possible

Answer 11

first

Question 12

(True or False)
It is necessary to indicate the position of the double bond in the name because its always C3 and C4

Answer 12

False
(not necessary; C1 and C2)

Question 13

=CH2 substituent is called a

Answer 13

methylene group

Question 14

H2C=CH- substituent is called a

Answer 14

vinyl group

Question 15

H2C=CHCH2- substituent is called an

Answer 15

allyl group

Question 16

is used to help draw chemical structures in organic chemistry

Answer 16

Degree of unsaturation or Index of Hydrogen Deficiency (IHD)

Question 17

each ring or double bond in a molecule corresponds to a loss of ______hydrogens from the alkane formula CnH2n+2.

Answer 17

two

Question 18

If IHD is equal to 0

Answer 18

single bonds only; no ring structures

Question 19

If IHD is equal to 1

Answer 19

1 double bond or 1 ring

Question 20

If IHD is equal to 2

Answer 20

1 triple bond, 2 double bonds, 2 rings, or 1 double bond and ring

Question 21

If IHD is equal to 3

Answer 21

2 double bonds and ring

Question 22

If IHD is equal to 4

Answer 22

benzene ring

Question 23

The _____ is used to calculate the number of rings and pi bonds there is/are in a molecule.

Answer 23

IHD

Question 24

(True or false)
cis and trans isomers of alkenes do not have the same stability

Answer 24

true

Question 25

caused by crowding of two alkyl groups on the
same side of a double bond

Answer 25

steric strain

Question 26

cis isomers is ____ than trans isomers

Answer 26

less stable

Question 27

(True or false)
The greater the number of attached alkyl groups, the lesser is the alkene’s stability

Answer 27

false
(greater)

Question 28

a stabilizing interaction between the C=C
π bond and adjacent C – H sigma bonds on substituents.

Answer 28

hyperconjugation

Question 29

(True or false)
a bond between an sp2 carbon and an sp3 carbon is somewhat stronger than a bond between two sp3
carbons

Answer 29

true

Question 30

first 3 members (C2 to C4) are _____ in nature

Answer 30

gaseous

Question 31

next 14 members (C4 to C18) are______

Answer 31

liquids

Question 32

greater than C19 are

Answer 32

solids

Question 33

alkenes are colorless and odorless (except_____, a colorless gas with a faintly sweet odor)

Answer 33

ethene

Question 34

Alkenes are insoluble in water but completely soluble in nonpolar solvents such as benzene

Answer 34

true

Question 35

(True or false)
Alkene’s boiling point increases with decreasing number of C atoms (increasing molecular weight)

Answer 35

false
(increasing)

Question 36

(True or False)
as carbon increases, LDF strength increases

Answer 36

true

Question 37

In alkenes, boiling point ___ in increasing branching

Answer 37

decreases

Question 38

(true or false)
cis-isomers have a greater melting point than trans-isomers

Answer 38

false
(lower)

Question 39

1,2-Elimination reactions is also called

Answer 39

β-Eliminations

Question 40

is an empirical rule used to predict the major
products of elimination reactions

Answer 40

Zaitsev’s rule

Question 41

It states that in an elimination reaction, the major product is the more stable alkene with the more highly substituted double bond

Answer 41

Zaitsev’s rule

Question 42

E2 rxn is

Answer 42

elimination bimolecular

Question 43

occurs when a migrating group with its pair of electrons moves from an adjacent carbon to the
carbon bearing the positive charge

Answer 43

carbocation rearrangement

Question 44

The carbon that loses the migrating group acquires the ______ charge

Answer 44

positive

Question 45

Rearrangement results to the formation of a ____________

Answer 45

more stable carbocation

Question 46

in which a hydrogen, with its pair of electrons, is the migrating group

Answer 46

hydride shift

Question 47

in which the alkyl group is the migrating group.

Answer 47

alkyl shift