1. Brown, LeMay Ch 25 AP Chemistry
Organic Chemistry
Brown, LeMay Ch 25
AP Chemistry

2. 25.1: Organic Chemistry
The study of carbon compounds, but not limited to living systems
Biochemistry: study of the chemistry of living things
Functional group: a group of atoms which determine how a molecule functions or reacts
A part of a molecule that is not part of the “base” carbon chain
Also called a substituent

3. 25.2: Intro to Hydrocarbons
Compounds composed of only C and H
Combust to form CO2 and H2O
Types:
Alkanes: contain only single C-C bonds
Also called saturated (contain the maximum # of H’s)
Unsaturated: contain < maximum # of H’s
Alkenes: contain at least one C=C bond
Alkynes: contain at least one C≡C bond
Aromatics: C’s connected in a planar ring (contain s and p bonds) and have delocalization

4. 25.3: Alkanes Lewis structure vs. condensed structural formula
Ex: C4H10
H3C–CH2–CH2–CH3
CH3CH2CH2CH3

5. Structural isomers
Compounds with same formula but different structures (different bonding arrangements)
Free rotation around C-C bonds limits number of isomers of alkanes
* Straight-chain
n- all C in a continuous chain
* Branched
iso- one CH3 branched off
t- or neo- lower-case “t”-shaped
“n-” means normal
There are 18 possible isomers for C8H18, and 75 possible isomers for C10H22.

6. Ex: Draw all the structural isomers for...
CH4 C2H6
C3H8
C4H10
C5H12

7. Organic Nomenclature prefix base suffix What substituents?
What “family”?
How many carbons?
Originally formulated by IUPAC in 1892 (
Find the longest continuous chain of C atoms; use the name of this chain as the base of the compound’s name.
1 = meth- 2 = eth- 3 = prop- 4 = but- 5 = pent-6 = hex- 7 = hept- 8 = oct- 9 = non- 10 = dec-
IUPAC = International Union of Pure and Applied Chemistry

8. Number the C atoms in the longest chain, beginning with the end nearest to a substituent. If different substituents are present, give the lowest number to the substituent with highest priority (see list). (
Name and give the location (carbon #) of each substituent as prefixes or suffixes. (It varies.)
When 2 or more substituents are present, name them in alphabetical order as prefixes
When 2 or more of the same substituents are present, use a Greek prefix (di-, tri-, tetra-, penta-, hexa-, …)

9. Ex: Name all the molecules. CH4 C2H6 C3H8
methane
ethane
propane
butane
2-methylpropane
pentane
2,2-dimethylpropane
2-methylbutane

10. Saturated hydrocarbons
Alkanes: CnH2n+2; suffix is -ane
Cycloalkanes: CnH2n (n>2); prefix is cyclo-
C’s bonded in a ring; not planar like an aromatic compound (except cyclopropane)
Ex: Draw Lewis structures of the first 4 cycloalkanes and name them.
cyclobutane
cyclopropane
cyclopentane
cyclohexane

11. 25.4: Unsaturated hydrocarbons
Alkenes: CnH2n; prefix is bond #; suffix is –ene
(more than one double bond: –diene, -triene)
Geometrical isomers: same formula & same groups, but different structures.
cis- groups with highest priority on same side of
bond axis (high priority = high atomic mass)
trans- groups with highest priority diagonal/across the
double bond
Ex: Draw and name all the isomers of C4H8. y y x x

12. Alkynes: CnH2n-2; prefix is bond #; suffix is –yne
Reactions: unsaturated molecules are more chemically reactive than saturated compounds
Addition: H3C-C≡C-CH3 + Br2 → ?
Hydrogenation:
CH3-CH=CH-CH3 + H2 → ?
→ H3C-C=C-CH3 | Br
Br―Br
Manufacturers hydrogenate the oil in peanut bitter so it will not separate from the peanut part.
→ H3C-CH―CH-CH3 | H
H―H

13. Aromatics: named like alkanes, but primarily based on benzene
Prefix describes relative positions of substituents:
ortho- 2 substituents next to each other
meta- 2 substituents separated by one C
para- 2 substituents separated by two C’s
ortho-
meta-
para-
Naphthalene: “mothballs”

14. 25.4 – 25.5: Functional Groups Notation: “R” stands for:
Alkyl group, such as -CH3
-C2H5
-C3H7, etc. H

15. Ester Name of group Formula of group Suffix Name Example structure
Example chemical name
Carboxylic acid O ||
R-C-OH or
“R-COOH”
-oic acid
Ester
R-C-O-R
“R-COOR”
-yl ___oate

16. Ketone R-O-H Alcohol “R-OH” -al -one -ol (suffix if highest priority)
Aldehyde O ||
R-C-H or
“R-CHO”
-al
Ketone
R-C-R
-one
Alcohol
R-O-H
“R-OH”
-ol (suffix if highest priority)
hydroxyl- (prefix if lower priority)

17. Ether
R-C-O-C-R
___ ether
Amine
R-NH2
-amine
NH2
NH2

18. (bromo-, chloro-, fluoro-, iodo-)
Alkene
\ / C=C / \
-ene
Alkyne
R-C≡C-R
-yne
Halide
R-X
halo-
(bromo-, chloro-, fluoro-, iodo-)

19. C ring with double bond(s)
Cycloalkane
C ring
cyclo-___-ane
Cycloalkene
C ring with double bond(s)
cyclo-___-ene
Alkane
-(CH2)n-CH3
-yl

20. *25.7: Chirality
Chiral: a molecule having a nonsuperimposable mirror image
(Originally discovered by Louis Pasteur)
Compounds containing C atoms with four different substituents are inherently chiral
Optical isomers or enantiomers: nonsuperimposable mirror images
Labeled “L” (levo, left-handed) and “D” (dextro, right-handed)
Racemic: a mixture containing both enantiomers (both L and D)