Chapter 4

Question 1

curved arrows

Answer 1

a bond is forming or breaking

Question 2

4 main ways electrons move in polar reactions

Answer 2

1. nucleophilic attack
2. loss of leaving group
3. proton transfer (acid/base)
4. rearrangements

Question 3

nucleophilic attack

Answer 3

nucleophile attacks an electrophile
(tail of arrow starts on electrons and end on the nucleus to share a bond)

Question 4

loss of a leaving group

Answer 4

heterolytic bond cleavage, an atom or group takes an electron pair (creates more lone pairs)

Question 5

proton transfers

Answer 5

the deprotonation of a compound (proton removed and electrons added?)

Question 6

rearrangements

Answer 6

carbocations can be stabilized by neighboring groups through slight orbital overlapping called hyperconjugation

Question 7

homolytic cleavage

Answer 7

half arrows, movement of free radicals

Question 8

heterolytic cleavage

Answer 8

full arrows, result in ions

Question 9

stability of free radicals

Answer 9

3>2>1>methyl

Question 10

stability of carbocations

Answer 10

3>2>1>methyl+

Question 11

stability of carbanions

Answer 11

-methyl>1>2>3

Question 12

Steps to Chlorination of Methane

Answer 12

1. initiation
2. propogation
3. termination

Question 13

Chlorination of Methane: initiation

Answer 13

generates a radical

Question 14

Chlorination of Methane: propogation

Answer 14

• something we made + something we started with to produce something reactive
• will go until terminated

Question 15

Chlorination of Methane: termination

Answer 15

side reactions that destroy the reactive intermediate

Question 16

Energy for the Chlorination of Methane: lower the Ea, _______ the rate, so more __________ intermediate is formed

Answer 16

faster, stable

Question 17

Hammond Postulate: endothermic

Answer 17

transition state resembles the product

Question 18

Hammond Postulate: exothermic

Answer 18

transition state resembles the reactant

Question 19

radical inhibitor

Answer 19

an inhibitor combines with a free radical to form a more stable molecule, create a slow endothermic reaction

Question 20

early transition states are often a characteristic of fast _________ processes, while late transition states are often a characteristic of reverse

Answer 20

exothermic

Question 21

the hammond postulate states that reactions which are thermodynamically _________________ and kinetically slow have transition states that occur late in the reaction time frame and resemble the products

Answer 21

endothermic

Question 22

carbocation

Answer 22

positively charged carbon

Question 23

carbocation: inductive effect

Answer 23

stabilizesa carbocation by the donation of electron density along sigma bonds

Question 24

carbocation: hyperconjugation

Answer 24

stabilizes a carbocation by an overlap of sigma bonding orbitals with empty p orbitals

Question 25

carboanions

Answer 25

• 8 electrons (6 bonding and 1 lone pair), negative charge
• a more powerful base and a stronger nucleophile than an amine

Question 26

carbenes

Answer 26

neutral, vacant p orbital and lone pair of electrons in the sp2 orbital so it can act as both an electrophile and a nucleophiles