Chapter 3

Question 1

Hydrocarbons only contain __ and __

Answer 1

Carbons and Hydrogens

Question 2

a hydrocarbon that contains only single bonds is said to be _______ because it has the maximum # of the bonded H possible

Answer 2

saturated

Question 3

if double or triple bonds are present in a hydrocarbon, it is considered _______

Answer 3

unsaturated

Question 4

Alkanes: backbond of most organic compounds contain only _______ bonds

Answer 4

sigma

Question 5

What is the general formula for alkanes? (molecular formula)

Answer 5

C(n) H(2n+2)

Question 6

The general formula applies to _______ and _______ isomers of alkanes

Answer 6

branched and unbranched

Question 7

IUPAC names of Alkanes: _______ + ANE

Answer 7

root

Question 8

What are the rules for nomenclature of alkanes?

Answer 8

1) find the longest chain
- when equal lengthmore branches = better
2) Number the carbons
3) Name the alkyl groups (substituents)
4) Assemble the name
- use hypens and commas and list substituents alphabetically

Question 9

Primary carbons (1°) are bonded to __other carbon
Secondary carbons (2°) are bonded to __other carbon
Tertiary carbons (3°) are bonded to __ other carbon
Quaternary carbons (4°) are bonded to __ other carbon
These only apply to _______ bonds

Answer 9

1
2
3
4
sigma

Question 10

Complex groups: substituent as though it were itself a compound
- name a complex substituent as though it were itself a compound
- REMEMBER: use “__” suffix to represent substituents
- _____ are used to represent complex groups systematically
- number always begins at the carbon bonded to the _____ chain

Answer 10

yl
parenthesis
root

Question 11

What are the 4 common names for the complex groups we need to know?

Answer 11

isopropyl
isobutyl
sec-butyl
tert-butyl

Question 12

Prefixes (di, tri, tetra, etc, and sec, and tert) are _______ in alphabetization

Answer 12

ignored

Question 13

the term Iso and cycle (rings) _______ counted for alphabetization

Answer 13

are

Question 14

haloalkanes are named like alkanes with the halogens treated as a _______

Answer 14

substituent

Question 15

What is the substituent name for F, Cl, Br, and I

Answer 15

Fluoro
Chloro
Bromo
Iodo

Question 16

Alkanes are primarily used as fuels, solvents, and lubricants. They are the _______ reactive class of organic compounds

Answer 16

least

Question 17

Alkane properties
1) _______
2) _______ (do not dissolve in water)
3) only _______ forces present
4) ___ bp-> increases with increasing __ and __
5) __ mp-> increases with increasing __
- even # of carbons = _______ temperature to melt
- odd # of carbons = _______ temperature to melt

Answer 17

1) nonpolar
2) hydrophobic
3) dispersion
4) low; MW; SA
5) low: MW
- higher
- lower

Question 18

C-C sigma bonds are allowed to _______ which results in different conformations

Answer 18

rotate

Question 19

In Newman Projections, what is the angle between the hydrogens called?

Answer 19

dihedral angle

Question 20

_______ strain: resistance to twisting

Answer 20

torsional

Question 21

What are the 2 Newman projections for ethane?

Answer 21

eclipsed and staggered

Question 22

Which form of ethane is more stable? (eclipsed or staggered)

Answer 22

staggered

Question 23

What are the 4 Newman projections for butane?

Answer 23

1) totally eclipsed
2) gauche
3) eclipsed
4) anti

Question 24

Rank the 4 Newman projections from least stable to most stable

Answer 24

totally eclipsed < eclipsed < gauche < anti

Question 25

_______ strain: interference between two large groups that are so close that their electron clouds experience repulsion

Answer 25

Steric

Question 26

_______ is preferred over _______ strain

Answer 26

steric is preferred over torsional

Question 27

What is the general formula for cycloalkanes?

Answer 27

C(n) H(2n)

Question 28

When multiple substituents are present in cycloalkanes, what are the 3 rules in order of most important to least important

Answer 28

1) lowest possible # given to substituents
2) most substituents
3) alphabetization of substituents

Question 29

When naming and a ring and branch are the same length, choose the _______ as the root

Answer 29

ring

Question 30

NEVER number into or out of a _______

Answer 30

ring

Question 31

What bond angle does the optimum orbital overlap require?

Answer 31

109.5

Question 32

Heat of combustion: the amount of heat released when a compound is burned. If a compound has extra energy because of _______ strain, it is released in combustion

Answer 32

ring

Question 33

cyclobutane has _____ angle strain and _____ torsional strain compared to cyclopropane

Answer 33

less
less

Question 34

Cyclic compound with 4 or more carbons adopt _______ conformations to relieve ring strain

Answer 34

non-planar

Question 35

cyclopentane:
1) _______ angle strain
2) _______ torsional strain (if planar)
- actual conformation is nonplanar known as (_______)
- shape is f______
3) _______ ring strain

Answer 35

less
considerable
pucured or envelop
fluctional
low

Question 36

Cyclohexane chair conformation:
_____ angle strain
_____ torsional strain
_____ ring strain

Answer 36

no
no
no

Question 37

Cyclohexane boat conformation:
_____ angle strain
_____ torsional strain
_____ steric strain

Answer 37

no
yes
yes

Question 38

Cyclohexane twist-boat conformation:
_____ angle strain
_____ torsional strain (compared to boat)
_____ steric strain (compared to boat)

Answer 38

slight
less
less

Question 39

What are the 2 orientations of substituents in chair conformations?

Answer 39

1) axial
2) equatorial

Question 40

If the cyclohexane ring is substituded with a group other than H, the two chair conformations (are/aren’t) equal in energy

Answer 40

aren’t

Question 41

Ring-flipping interconverts ______ axial and equatorial positions!!

Answer 41

All

Question 42

Given an option, _______ groups prefer to be equatorial to avoid the steric strain from _______

Answer 42

larger
1,3-diaxial interactions

Question 43

Chair conformation is most stable unless you have _______, then twist boat is the most stable

Answer 43

2 tert-butyl groups