Chapter 3 Flashcards
Hydrocarbons only contain __ and __
Carbons and Hydrogens
a hydrocarbon that contains only single bonds is said to be _______ because it has the maximum # of the bonded H possible
saturated
if double or triple bonds are present in a hydrocarbon, it is considered _______
unsaturated
Alkanes: backbond of most organic compounds contain only _______ bonds
sigma
What is the general formula for alkanes? (molecular formula)
C(n) H(2n+2)
The general formula applies to _______ and _______ isomers of alkanes
branched and unbranched
IUPAC names of Alkanes: _______ + ANE
root
What are the rules for nomenclature of alkanes?
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
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
1
2
3
4
sigma
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
yl
parenthesis
root
What are the 4 common names for the complex groups we need to know?
isopropyl
isobutyl
sec-butyl
tert-butyl
Prefixes (di, tri, tetra, etc, and sec, and tert) are _______ in alphabetization
ignored
the term Iso and cycle (rings) _______ counted for alphabetization
are
haloalkanes are named like alkanes with the halogens treated as a _______
substituent
What is the substituent name for F, Cl, Br, and I
Fluoro
Chloro
Bromo
Iodo
Alkanes are primarily used as fuels, solvents, and lubricants. They are the _______ reactive class of organic compounds
least
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
1) nonpolar
2) hydrophobic
3) dispersion
4) low; MW; SA
5) low: MW
- higher
- lower
C-C sigma bonds are allowed to _______ which results in different conformations
rotate
In Newman Projections, what is the angle between the hydrogens called?
dihedral angle
_______ strain: resistance to twisting
torsional
What are the 2 Newman projections for ethane?
eclipsed and staggered
Which form of ethane is more stable? (eclipsed or staggered)
staggered
What are the 4 Newman projections for butane?
1) totally eclipsed
2) gauche
3) eclipsed
4) anti
Rank the 4 Newman projections from least stable to most stable
totally eclipsed < eclipsed < gauche < anti
_______ strain: interference between two large groups that are so close that their electron clouds experience repulsion
Steric
_______ is preferred over _______ strain
steric is preferred over torsional
What is the general formula for cycloalkanes?
C(n) H(2n)
When multiple substituents are present in cycloalkanes, what are the 3 rules in order of most important to least important
1) lowest possible # given to substituents
2) most substituents
3) alphabetization of substituents
When naming and a ring and branch are the same length, choose the _______ as the root
ring
NEVER number into or out of a _______
ring
What bond angle does the optimum orbital overlap require?
109.5
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
ring
cyclobutane has _____ angle strain and _____ torsional strain compared to cyclopropane
less
less
Cyclic compound with 4 or more carbons adopt _______ conformations to relieve ring strain
non-planar
cyclopentane:
1) _______ angle strain
2) _______ torsional strain (if planar)
- actual conformation is nonplanar known as (_______)
- shape is f______
3) _______ ring strain
less
considerable
pucured or envelop
fluctional
low
Cyclohexane chair conformation:
_____ angle strain
_____ torsional strain
_____ ring strain
no
no
no
Cyclohexane boat conformation:
_____ angle strain
_____ torsional strain
_____ steric strain
no
yes
yes
Cyclohexane twist-boat conformation:
_____ angle strain
_____ torsional strain (compared to boat)
_____ steric strain (compared to boat)
slight
less
less
What are the 2 orientations of substituents in chair conformations?
1) axial
2) equatorial
If the cyclohexane ring is substituded with a group other than H, the two chair conformations (are/aren’t) equal in energy
aren’t
Ring-flipping interconverts ______ axial and equatorial positions!!
All
Given an option, _______ groups prefer to be equatorial to avoid the steric strain from _______
larger
1,3-diaxial interactions
Chair conformation is most stable unless you have _______, then twist boat is the most stable
2 tert-butyl groups
