I. 2.1 BACKGROUND AND INTRODUCTION (NOMENCLATURE)
A. Basic nomenclature
| Carbon Chain Prefixes and Alkane Names | |||
| # of C atoms in a row | Prefix | Alkane | Name |
| 1 | Meth- | CH4 | Methane |
| 2 | Eth- | CH3CH3 | Ethane |
| 3 | Prop- | CH3CH2CH3 | Propane |
| 4 | But- | CH3(CH2)2CH3 | butane |
| 5 | Pent- | CH3(CH2)3CH3 | Pentane |
| 6 | Hex- | CH3(CH2)4CH3 | Hexane |
| 7 | Hept- | CH3(CH2)5CH3 | Heptane |
| 8 | Oct- | CH3(CH2)6CH3 | Octane |
| 9 | Non- | CH3(CH2)7CH3 | Nonane |
| 10 | Dec- | CH3(CH2)8CH3 | Decane |
Nomenclature for Substituents
| Nomenclature for Substituents | |
| -CH3 | Methyl |
| -CH2CH3 | Ethyl |
| -CH2CH2CH3 | Propyl |
| H3C-CH-CH3⃒ | Isopropyl |
| -CH2CH2CH2CH3 | Butyl (or n-butyl) |
| CH3CHCH2CH3⃒ | sec-butyl |
| CH3 ⃒-C-CH3⃒CH3 | tert-butyl (or t-butyl) |
B. Common functional groups
II. 2.2 ABBREVIATED LINE STRUCTURE
III. 2.3 NOMENCLATURE OF ALKANES
A. Rules
1. Identify the longest chain of carbons (7 carbons, hept-)
2. Identify substituents: there are 3 methyl groups and 1 isopropyl goup
3. Number the carbon chain so substituents have the lowest #
a) 2-methyl, 3-methyl, 3-methyl, 4-isopropyl
4. Identical substituents are grouped together with the prefixes di-, tri-, etc to denote how many there are; numbers are separated by a comma
a) 2,3,3-trimethyl
5. Alphabetize the substituents, ignoring prefixes (di-, iso-, etc); separate numbers from words by hyphen and numbers from numbers by comma
a) 2,3,3-trimethyl-4-isopropylheptane
IV. 2.4 NOMENCLATURE OF HALOALKANES
A. Fluorine = fluoro-
B. Chlorine = chloro-
C. Bromine = bromo-
D. Iodine = iodo-
V. 2.5 NOMENCLATURE OF ALCOHOLS
A. Replace the “e” with “ol” in the last part of an alkane to name alcohol
1. methane → methanol
B. Position of the hydroxyl group
When the position of the hydroxyl group needs to be specified, the number is placed after the name of the longest carbon chain, but before the “ol” suffix, separated by hyphens
C. Priorities are assigned to give the hydroxyl group the lowest number
VI. 2.6 Video notes
A. Properties of Alkanes
1. Branching and molecular weight: melting point and boiling point
a) Increase MW → increase MP and increase BP
b) Increase branching → decrease MP and decrease BP
2. Hydrogen bonding (H connected to F, O, or N)
a) Increase H-bonding → increase MP and BP
3. Reactivity vs stability:
| Stability | Reactivity | |
| Carbocations(a C loses atom as well as e–) | 3º>2º>1º | 1º>2º>3º |
| Radical(dangling bond – 1 e–) | 3º>2º>1º | 1º>2º>3º |
| Carbanion(a C loses the atom, but not e–) | 1º>2º>3º | 3º>2º>1º |
4. ACIDITY TRENDS → acids donate protons, accepts e-s, or decreases pH
a) More stable of a conjugate base (usually due to resonance), the more acidic
b) Strong acid has weak conjugate base (means base is not reactive b/c it is stable)
c) Trends that increase acidity:
(1) resonance increases acidity (ex, phenol)
(2) + charge (OH–, H2O, H3O+) the H3O+ is most acidic
(3) Inductive effect – the more electronegative atoms near the acid, the more acid
(4) → right on periodic table = increasing acidity
d) Memorize:
| Strong acids | Strong bases |
| H2SO4 | Group I and II hydroxides |
| HNO3 | Na, K, Rb, Cs, Ca, Ba, Sr |
| HI | |
| HBr | |
| HCl | |
| HClO4 |
e) Weak acids, from strong to weak
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(3) Alcohols >
(4) Aldehydes >
(5) Ketones >
(6) Alkynes >
(7) Akenes >
(8) Alkanes
