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CHM 103 GENERAL CHEMISTRY
SPRING QUARTER 2004
Lesson Plan – 6/8/2004
A. Quiz at 12:00.
B. Hand in your extra credit (pH meter calibration) assignments.
C. Organic Chemistry (Just a Wee Taste)
1. Introduction
2. Saturated Hydrocarbons
3. Unsaturated Hydrocarbons
4. Aromatic Hydrocarbons
5. Organics Containing Oxygen
6. Organics Containing Nitrogen
7. Isomerism
8. Polymers
D. Introduction
1. >90% of all chemical compounds contain carbon. Reason: It is easy to
form chains and rings containing C-C bonds.
2. Organics tend to be molecular (rather than ionic).
3. Four covalent bonds on a carbon atom.
4. Favorite bonding partners: C, H, O, N, F, Cl, Br, I, S, P.
5. Numbers of bonds:
C
4
H, F, Cl, Br, I
1
O, S
2
N, P
3
E. Saturated Hydrocarbons (Alkanes)
1. Made up only of C and H.
2. C’s are formed into chains (except methane).
3. C--C bonds are all single bonds with (nearly) free rotation.
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4. Tetrahedral geometry about C – in methane (CH4), all H--H distances are
the same.
5. Chains may be “straight” or branched. Butane and 2-methylpropane (also
called n-butane and isobutane) are structural isomers.
6. Structural isomers are distinct chemical compounds with different boiling
points, etc., despite having the same atomic compositions and molecular
weights.
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7. Typical alkanes:
a. Natural gas: methane (CH4) and ethane (C2H6).
b. Bottle gas: propane (C3H8) and butane (C4H10).
c. Gasoline: mixture in C5 to C9 range.
d. Fuel oil.
e. Lubricating oil.
f. Asphalt.
g. Crude oil (a mixture with wide range of b. p.’s). Separated into
useful components by fractional distillation.
F. Unsaturated Hydrocarbons (Alkenes and Alkynes)
1. Characterized by one or more multiple bonds (we will consider only
simple alkenes, having one double bond, and simple alkynes, having one
triple bond).
2. Alkenes
a. One carbon-carbon double bond.
b. General formula: CnH2n
c. No rotation about the double bond.
d. The double bond is considerably more reactive than a C--C
single bond.
e. Geometry at double bond (>C=C<) is planar.
f. Ethylene (ethane) and propylene (propene) are simplest
examples.
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3. Alkynes
a.
b.
c.
d.
One carbon-carbon triple bond.
General formula: CnH2n-2
Geometry at triple bond is linear.
Acetylene is simplest example.
G. Aromatic Hydrocarbons and Their Derivatives
1. Characterized by planar, ringed structures.
2. Benzene, C6H6, is simplest example.
3. Benzene has a six membered ring structure
 6 identical C—C bonds
 the bond angles are all 120°
 the 6 carbons are coplanar
 valence bond picture (resonance hybrid structure):

molecular orbital picture:


each vertex represents a C atom
one H is bonded to each C (H atoms and C—H bonds not shown)
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 the circle represents the 6 delocalized “pi” electrons
4. Some Common Derivatives of Benzene
5. Condensed Ring Structures
 condensed rings are generally planar
 graphite and coal contain large sheets of condensed rings
H. Organics Containing Oxygen
1. Alcohols: Organics containing –O—H (hydroxyl) groups
a. Methanol (methyl alcohol): CH3OH
 Imagine methane (CH4) with one H replaced by OH (but it is
not made this way)
 Generally manufactured from synthesis gas (CO + H2) under
conditions of high temperature and pressure and using catalyst:
CO(g) + 2H2(g)  CH3OH(g)
b. Ethanol (ethyl alcohol): C2H5OH
 Generally made by fermentation of sugar
 Industrial grade made by reacting ethylene with water (and
sulfuric acid as catalyst)
c. Multi-Hydroxyl Alcohols
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2. Carboxylic Acids: Organics containing –COOH (carboxyl) groups
a. Carboxyl structure
b. Formic Acid (HCOOH): the simplest carboxylic acid
c. Acetic Acid (CH3COOH): the most familiar


This is the same acetic acid we classed as a weak acid in
chapter 13 and wrote: HC2H3O2.
Even if we write it as CH3COOH, we can still react it with
strong base to produce an acetate salt:

A similar reaction can convert stearic acid into a soap.
3. Esters: Organics containing –COO– groups (ester linkages)
a. Structure of an ester linkage:
b. Make an ester by reacting an alcohol with a carboxylic acid to
eliminate water and generate an ester:
c. Names of esters:
 The first name of the ester is the same as the first name of the
alcohol.
 The second name of the ester is like the first name of the acid,
except that you change the “-ic” suffix to “-ate.”
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
Example: the ester obtained from the reaction of ethyl alcohol
and formic acid is called “ethyl formate.”
4. Other Oxygen-containing Organics – See Table 22.1
a. Ethers (–O–)
b. Aldehydes (–CHO)
c. Ketones (–CO–)
I. Organics Containing Nitrogen
1. (Primary) Amines: Organics containing –NH2 (primary amine) groups
a. Simplest member is methyl amine: CH3NH2
b. Another is aniline: C6H5NH2 (we saw this earlier as a benzene
derivative)
2. Amides: Organics containing carbonyl linked to nitrogen
a. Structures of amides
b. Amide types (a), (b), and (c) all contain an amide linkage
[–(C=O)NH–]
c. React an amine with a carboxylic acid to eliminate water and
generate an amide
 Amide type (a) is the reaction product of ammonia with a
carboxylic acid, for example:
CH3COOH + NH3  CH3CONH2 + H2O
 Amide type (b) is the reaction product of a primary amine, such
as methyl amine, with a carboxylic acid, for example:
CH3COOH + CH3NH2  CH3CONHCH3 + H2O
 Amide type (c) is the reaction product of a secondary amine,
such as dimethyl amine, with a carboxylic acid.
3. Amino Acids: Organics containing both a carboxyl group and an amine
group
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a. If the amine is substituted on the carbon that is next to the
carboxyl group, we have an alpha-amino acid. Some examples,
recovered from proteins, are shown in the following table:
b. An amino acid is capable of forming two amide linkages, one
with its N, the other with the C in its carboxyl group.
c. Groups of alpha-amino acids can react to form chains whose
backbones contain repeated peptide units: –NHCHRCO– , for
example: (The R groups are characteristic of the various amino
acids.)
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