1. Brown, LeMay Ch 25 AP Chemistry Monta Vista High School
Organic Chemistry
Brown, LeMay Ch 25
AP Chemistry
Monta Vista High School
Problem Set: #5, 7, 9, 10, 11, 15, 20, 23 (not c), 41(not c), 44; Recommended: #2, 16, 17, 43, 69

2. 25.1: Organic Chemistry
The study of carbon compounds, but not limited to living systems
Biochemistry: study of the chemistry of living things
Hydrocarbons are Compounds composed of only C and H
Combust to form CO2 and H2O
Hydrocarbons have a
-parent carbon chain: It is the longest continuous carbon chain (does not have to be straight)
- and a side substituent: Ex: alkyl groups

3. 25.2: Intro to Hydrocarbons
Types:
Alkanes: contain only single C-C bonds. General formula Cn H2n+2, ending -ane
Also called saturated (contain the maximum # of H’s)
Ex. Methane, Ethane etc.
Unsaturated: contain < maximum # of H’s
Alkenes: contain at least one C=C bond. General Formula CnH2n, ending - ene
Alkynes: contain at least one C≡C bond. General Formula CnH2n-2, ending - yne
Aromatics: C’s connected in a planar ring (contain s and p bonds) and have delocalization. Contain benzene ring, ex: benzene, chlorobenzene

4. How many carbons in longest chain?
Organic Nomenclature
prefix
base
suffix
What substituents?
What “family”?
How many carbons in longest chain?
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. This is called the parent carbon chain.
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

5. 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 on the website). The idea is to number the parent carbon chain to give the side substituents the lowest numbering.
Priority List: carboxylic acid> aldehyde> ketone>alcohol> double or triple bond> alkyl group

6. 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-, …)
Examples:

7. 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
cyclohexane
cyclopropane

8. Ways to represent Organic Compounds
Molecular Formula Ex: C4H10 condensed formula Ex: H3C–CH2–CH2–CH3 or CH3CH2CH2CH3 CH3CH2CH2CH3 Structural formula Ex:

9. Understanding Check
Draw condensed formula and structural formula for the following: C3H8

10. Ex: Name all the molecules. CH4 C2H6 C3H8 C4H10 C5H12
methane
ethane
propane
butane
2-methylpropane
pentane
2,2-dimethylpropane
2-methylbutane

11. Write the name of the following:
______________________ ______________________
______________________ ______________________

12. ______________________ ______________________
_______________________ ______________________

13. Draw condensed structural formulas for the following hydrocarbons:
2,3-dimethylpentane
2,4-dimethylhexane
Cyclohexane
2,2-dimethylpropane
2,4-dimethyl-1-hexene

14. 2,4,6-trinitromethylbenzene
cis-2,3-dichloro-2-butene
1,1,2-trichloroethane
1,2-methylcyclohexane
1,4-dichlorobenzene
1-chloro-2-butyne
1,3-cyclohexadiene

15. 25.4 – 25.5: Functional Groups Notation: “R” stands for:
Alkyl group, such as -CH3
-C2H5
-C3H7, etc. H
Carbonyls: contain a C=O

16. 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
methanoic acid
ethyl propanoate
propyl ethanoate

17. 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)
2-methyl- butanal
2-butanone
2,3-pentadiol

18. Ether Amine R-NH2 ___ ether -amine R-C-O-C-R diethyl ether NH2
2,2-pentadiamine
NH2

19. (bromo-, chloro-, fluoro-, iodo-)
Alkene
\ / C=C / \
-ene
Alkyne
R-C≡C-R
-yne
Halide
R-X
halo-
(bromo-, chloro-, fluoro-, iodo-)
1-propene
2-butyne
2-bromopropane

20. C ring with double bond(s) cyclo-___-ene
Cycloalkene
C ring with double bond(s)
cyclo-___-ene
Cycloalkane
C ring
cyclo-___-ane
Alkane
-(CH2)n-CH3
-yl (as functional group) or
-ane
1-cyclopentene
cycloheptane
2,3-dimethylbutane

21. Isomers:
Compounds with same molecular formula but different structures (different bonding arrangements)
There are two main types of isomers:
1. Structural Isomers: Same formula but differ in the arrangement of atoms around the carbon chain. Structural isomers can be:
a. branched chain (depending on C chain)
b. positional (position of a side group)
c. functional group isomers (position of a functional group).
2. Stereoisomers: Same formula but different 3-D orientation. They can be of two types:
a. Geometric Isomers ( cis, trans, double bonded C atoms only)
b. Optical Isomers (3D- orientation different- chirality)
“n-” means normal
There are 18 possible isomers for C8H18, and 75 possible isomers for C10H22.

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

23. 25.4: Geometric Isomers (cis-trans)
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

24. The essential requirement for this stereoisomerism is that each carbon of the double bond must have two different substituent groups (one may be hydrogen). This is illustrated by the following general formulas. In the first example, the left-hand double bond carbon has two identical substituents (A) so stereoisomerism about the double bond is not possible (reversing substituents on the right-hand carbon gives the same configuration). In the next two examples, each double bond carbon atom has two different substituent groups and stereoisomerism exists, regardless of whether the two substituents on one carbon are the same as those on the other.
Credits:

25. Optical Isomers
Two molecules are optical isomers if they are non super imposable, mirror images of each other.
Credit: Google Images

26. *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)
AA found in proteins are L

27. 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

28. 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”