Ch.7

Question 1

What is the energy in pi bonds

Answer 1

60-65 kcal/mol

Question 2

What is a degree of unsaturation

Answer 2

A pi bond or a ring

Question 3

How do you calculate unsaturation?

Answer 3

Use CnH2n+2, so how many Hs you are missing and divide that by 2

Question 4

Double bond Nomenclature

Answer 4

1. Find the longest carbon chain including the double-bonded carbons
2. Ending changes from -ane to -ene
3. Number the chain so the double has the lowest possible number

Question 5

In a ring, the double bond is assumed to be in between carbon ___ and _____

Answer 5

carbon 1 and 2

Question 6

Cis vs. Trans double bond

Answer 6

Cis: Both constituents are on the same side of the bond
Trans: Both constituents are on the opposite side of the bond

Question 7

When are trans cycloalkenes stable

Answer 7

When the ring has at least 8 carbons

Question 8

Determining E and Z

Answer 8

Number substituents according to atomic number
If groups are on opposite sides it’s E, if they are on the same size it’s Z

Question 9

Lower heat of hydrogenation means a chemical is ____ stable

Answer 9

more

Question 10

Bredt’s Rule

Answer 10

A bridged, bicyclic compound cannot have a double bond at a bridgehead positioin unless one of the rings contains at least eight carbon atoms

Question 11

What drives elimination reactions

Answer 11

Strong or weak bases

Question 12

How many groups are lost during an E1 Reaction

Answer 12

A hydrogen and a Halide

Question 13

A ________ acts as a base

Answer 13

Nucleophile

Question 14

E1 has the same conditions as ______

Answer 14

SN1

Question 15

E1 Rate Law

Answer 15

k[electrophile]

Question 16

Do you go through carbocations with E1

Answer 16

Yes! so you can still form SN1 products

Question 17

E1 forms the _____ stable alkenes because of the __-rule

Answer 17

most stable
Z-rule

Question 18

For E1 use a ______ and a ______ electrophile

Answer 18

Weak base
tertiary electrophile

Question 19

Does E1 product both cis and trans products

Answer 19

Yes

Question 20

Zaitsev’s Rule

Answer 20

If more than one elimination product is possible, the most substituted alkene is the major product

Question 21

E2 happens in ____ step(s)

Answer 21

one step; the proton is removed, the double bond forms, and the leaving group leaves all in one step

Question 22

E2 needs _______ orientation

Answer 22

Antiperplanar (cis)

Question 23

E2 order of reactivity

Answer 23

3º > 2º > 1º

Question 24

Hoffmann Orientation

Answer 24

Formed by bulky bases, The least stable alkene (the one with the least number of substituents on the carbons of the double bond) is formed

Question 25

If you have a 6 member ring, the leaving group and H need to be _____

Answer 25

axial

Question 26

How can alcohols be dehydrated

Answer 26

Using H2SO4 or H3PO4 to form an alkene and water using E1 mechanism

Question 27

What is catalytic cracking

Answer 27

A long chain-alkane is heated with a catalyst to produce an alkene and shorter alkane

Question 28

How can alkanes be dehydrogenated

Answer 28

H2 is removed, forming an alkene and H2