Final Exam

Question 1

Tosylate

Answer 1

Question 3

Constitutional Isomers

Answer 3

two structures with same molecular formula but **different connectivity **

Question 4

Electronegativity Trend on Periodic Table

Answer 4

increases from:

borrom to top of group

right → left of period

Question 5

Induction

Answer 5

withdrawal of electrons toward more EN atom

Question 6

Steric #

Answer 6

total number of s bonds

Question 7

Steric number indicates?

Answer 7

of e pairs that are repelling each other

Question 8

Steric number of 4

of lone pairs:

0

1

2

Answer 8

sp³

tetrahedral

trigonal planar

bent

Question 9

Steric number of 3

of lone pairs:

1

0

Answer 9

sp²

trigonal planar

bent

trigonal planar

Question 10

Steric number of 2

Answer 10

sp

linear

Question 11

dipole moment is an indicator of?

Answer 11

polarity

Question 12

Bronsted-Lowry Acid/Base

Answer 12

proton donor/acceptor

Question 13

NH_3, C=C, C≡C

strongest acids?

Answer 13

C=C < NH3 < C≡C

Question 14

(4) facors affect stability of a negative charge

Answer 14

1) Type of atom that carries charge
2) Resonance
3) Induction
4) Type of orbital where charge resides

Question 15

2 atoms: dominant effect when:

1) Same row
2) Same group

Answer 15

1) EN
- the more EN, the better it can stabilize (-) charge
2) Size
- larger atoms can spread charge over larger space which stabilizes (-) charge

Question 16

How does the type of orbital affect stability of the negative charge?

Answer 16

electrons in sp orbital held closer to nucleus than electrons of sp² and sp³

electrons are stabilized by being close to nucleus

Question 17

How do resonance effects make a conjugate base (or compound with negative charge) more stable?

Answer 17

charge is delocalized, therefore it is more stable

Question 18

How do inducive effects stablize a negative charge?

Answer 18

by withdrawing electron density away from negatively charged region, thereby stabilizing the negative charge

Question 19

equilibrium always favours formation of…

Answer 19

the more stable (weaker) base

(the more stabilzed negative charge)

Question 20

Lewis Acid/Base

Answer 20

electron pair acceptor/donor

Question 21

torsional strain

Answer 21

difference in energy between staggered and eclipsed conformation

Question 22

gauche interaction

Answer 22

steric interaction when two groups are seperated by 60˚

Question 23

Anti conformation

Answer 23

two groups are seperated by dihedral angle of 180˚

Question 24

Angle Strain

Answer 24

increase in energy associated with bond angle deviated from preferred angle of 109.5˚

Question 25

Most stable conformation of a cyclohexane ring

Answer 25

chair conformation

Question 26

In the chair conformation....

Answer 26

All the H's are staggered

Question 27

**Axial** position **Equatorial** position

Answer 27

parallel to vertical axis passing through center of ring positioned at angles parallel to sets of parallel lines making up chair

Question 28

Ring Flip

Answer 28

conformational change in which one chair conformation is converted into the other

Question 29

Which position is lower in energy (more stable)? Axial or Equatorial

Answer 29

equatorial

Question 30

1.3-diaxial interactions

Answer 30

the **steric interactions** between a **substituent** in **axial** position and **other axial H's** on **same** side of ring

Question 31

***1.3-diaxial interactions*** are equivalent to?

Answer 31

gauche interactions

Question 32

Stereoisomers

Answer 32

compounds with same molecular formula and sequence of bonded atoms (constitution) but differ in the 3D arrangement of atoms

Question 33

Isomers

Answer 33

nonidentical molecules with same formula

Question 34

Constitutional Isomers

Answer 34

differ in connectivity of atoms

Question 35

Enantiomer

Answer 35

stereoisomers that are nonsuperimposable mirror images of each other (chiral object)

Question 36

Chiral compounds always only have...

Answer 36

ONE enantiomer

Question 37

**R** and **S** configurations

Answer 37

right (R) and left (S)

Question 38

To redraw molecule in appropriate perspective to find if its R or S...

Answer 38

Switch group in 4th position with group on dash, and then switch the other two groups

Question 39

**Kinetics** refer to?

Answer 39

rate of reaction

Question 40

**Thermodynamics** refers to?

Answer 40

equilibrium concentrations of reactants and products

Question 41

electrophile

Answer 41

capable of accepting a pair of electons

Question 42

nucleophile

Answer 42

capable of donating a pair of electrons

Question 43

strength of a nucleophile is affect by many factors, including?

Answer 43

polarizability

Question 44

Polarizability

Answer 44

ability of an atom or molecule to distribute its electron density unevenly in response to external influence

Question 45

Polarizability is directly related to?

Answer 45

the size of the atom

Question 46

Carbocation arrangements dont usually occur when carbocation is already tertiary (3˚) unless?

Answer 46

a rearrangement will produce a resonance-stabilized carbocation

Question 47

allylic carbocation

Answer 47

positive charge is located at allylic position

Question 48

**Allylic** position

Answer 48

position next to double bond (alkene)

Question 49

**Substitution** Reaction

Answer 49

reaction in which one group is replaced by another group

Question 50

Good Leaving Groups

Answer 50

Halogens Conjugate bases or strong acids (weak bases)

Question 51

What determines reactivity for: SN1 SN2

Answer 51

carbocation stability steric hindrance

Question 52

SN2 and SN1 are not observed at?

Answer 52

sp2 centers backside attack - steric hindrance loss of LG produces unstable carbocation

Question 53

4 factors determing whether SN1 or SN2

Answer 53

1) substrate (1˚, 2˚, 3˚) 2) Nu 3) LG 4) Solvent

Question 54

Solvent: what solvents favor: a) SN1 b) SN2

Answer 54

a) **polar protic** - no H's connected to EN atom b) **polar aprotic** - H's connected to EN atom

Question 55

polar protic favours SN1 because?

Answer 55

it stabilizes polar intermediates and transition state

Question 56

polar aprotic stabilizes SN2 by?

Answer 56

raising energy of Nu giving a smaller E_a

Question 57

**Elimination** Reactions

Answer 57

type of organic reaction in which two substituents are removed from a molecule (H⁺ from ß position is removed with LG forming double bond) - **1,2 Elimination** or **ß Elimination**

Question 58

LG in: **a) Dehydrohalogenation** **b) Dehydration**

Answer 58

a) Halide b) Water

Question 59

E and Z configuration

Answer 59

E - opposite side of double bond Z - same side of double bond

Question 60

Alkenes are more stable when they are?

Answer 60

Highly substituted - electron effect (delocalization)

Question 61

Elimination Reactions always have which (2) steps?

Answer 61

**loss of LG** and **H⁺ transfer**

Question 62

**Zaitsev** vs **Hoffman** product

Answer 62

**Zaitsev** - more substitued **Hofmann** - less substituted

Question 63

Regiochemistry of E2 process can be controlled by?

Answer 63

choice of base

Question 64

Nucleophiles (only)

Answer 64

Halides (Cl, Br, I) Sulfur Nu's (HS^-, RS^-, H₂S, RSH)

Question 65

Base (only)

Answer 65

Hydride (H^- of NaH)

Question 66

Strong Nu/Strong Base

Answer 66

Question 67

Dehydration Reaction

Answer 67

elimination of water to form an alkene

Question 68

2 extra steps in E1

Answer 68

Question 69

tert-Butoxide favours?

Answer 69

E2 over SN2 when substrate is 1˚

Question 70

2˚ alcohol undergo E1 when?

Answer 70

H₂SO₄ + heat

Question 71

**Addition** Reaction

Answer 71

reverse of Elimination

Question 72

Addition or Elimination dependant on?

Answer 72

Temperature High - elimination Low - addition

Question 73

What bases will deprotonate a terminal alkyne?

Answer 73

alkane (with negative charge) H2N^- H^- Alkynide anion