9.2 Substituted Hydrocarbons
The electric drill can be
used to drill holes,
tighten a screw, or sand
a rough surface. To
change the function of
the drill, you replace, or
substitute, an
attachment.
twist drill bit
Forstner drill bit
hole saw bit
drum sander
Phillips screwdriver bit
9.2 Substituted Hydrocarbons
A carbon atom in an organic compound
can have four attachments.
• In a methane molecule, the carbon atom has
four identical attachments—its hydrogen
atoms.
• Chlorine atoms can replace hydrogen atoms.
CH4 + Cl2  CH3Cl + HCl
9.2 Substituted Hydrocarbons
Chloromethane and hydrogen chloride are
products of the reaction between methane
and chlorine.
Other products have two, three, or four
chlorine atoms.
Organic compounds containing chlorine or
other halogens are halocarbons.
9.2 Substituted Hydrocarbons
A hydrocarbon in which one or more
hydrogen atoms have been replaced by an
atom or group of atoms is a substituted
hydrocarbon.
The substituted atom or group of atoms is
called a functional group.
9.2 Substituted Hydrocarbons
Exploring Boiling Points of Chlorocarbons
Graph the data below, plotting boiling point
vs. number of chlorine atoms. Draw a smooth
curve connecting the points.
9.2 Substituted Hydrocarbons
Exploring Boiling Points of Chlorocarbons
9.2 Substituted Hydrocarbons
Exploring Boiling Points of Chlorocarbons
1. Using Graphs Predict the boiling point of
dichloromethane.
9.2 Substituted Hydrocarbons
Exploring Boiling Points of Chlorocarbons
1. Using Graphs Predict the boiling point of
dichloromethane.
Answer: The boiling point of dichloromethane is
40°C, but temperatures between –24°C and
61°C are acceptable.
9.2 Substituted Hydrocarbons
Exploring Boiling Points of Chlorocarbons
2. Relating Cause and Effect What effect does
increasing the number of chlorine atoms have on
the boiling point?
9.2 Substituted Hydrocarbons
Exploring Boiling Points of Chlorocarbons
2. Relating Cause and Effect What effect does
increasing the number of chlorine atoms have on
the boiling point?
Answer: As the number of chlorine atoms
increases, the boiling point increases.
9.2 Substituted Hydrocarbons
Exploring Boiling Points of Chlorocarbons
3. Formulating Hypotheses Why is the boiling
point of CH3Br higher than the boiling point of
CH3Cl? (Hint: Compare the atomic masses for
bromine and chlorine.)
9.2 Substituted Hydrocarbons
Exploring Boiling Points of Chlorocarbons
3. Formulating Hypotheses Why is the boiling
point of CH3Br higher than the boiling point of
CH3Cl? (Hint: Compare the atomic masses for
bromine and chlorine.)
Answer: Bromine is more massive than chlorine.
9.2 Substituted Hydrocarbons
Alcohols
What functional groups are found in
alcohols?
The functional group in an alcohol is a
hydroxyl group, –OH.
9.2 Substituted Hydrocarbons
Alcohols
Methanol and ethanol are alcohols.
• Methanol, CH3OH, is used as a fuel in some
motorcycles.
• Ethanol, CH3CH2OH, is often mixed with
gasoline to help the gasoline burn more
completely.
• The name of an alcohol ends in –ol.
9.2 Substituted Hydrocarbons
Alcohols
When a halocarbon reacts with a base, the
products are an alcohol and salt.
CH3Cl + NaOH  CH3OH + NaCl
An alcohol can also be made by reacting an
alkene with water.
9.2 Substituted Hydrocarbons
Organic Acids and Bases
What functional groups are found in organic
acids and organic bases?
The functional group in organic acids is a
carboxyl group, –COOH.
The functional group in an amine is an
amino group, –NH2.
9.2 Substituted Hydrocarbons
Organic Acids and Bases
The names of organic acids end in -oic.
Organic acids tend to have sharp tastes and strong
odors. The sharp, sour taste of a lemon comes from
citric acid, an organic acid.
The simplest organic acid is methanoic acid.
Vinegar is a solution of water and ethanoic acid (also
known as acetic acid).
9.2 Substituted Hydrocarbons
Organic Acids and Bases
Birds sometimes will
sit on an ants’ nest
and allow the ants to
crawl over them. The
methanoic acid
sprayed by the ants is
a natural pesticide
that kills mites in the
birds’ feathers.
9.2 Substituted Hydrocarbons
Organic Acids and Bases
Do you know the smell of rotten fish? Then
you’ve encountered a type of substituted
hydrocarbon called an amine. Amines are
organic bases.
Amines are found in paints, dyes, and
disinfectants.
9.2 Substituted Hydrocarbons
Esters
How are esters formed?
Esters form when organic acids react with
alcohols.
9.2 Substituted Hydrocarbons
Esters
Esters are a group of substituted
hydrocarbons. Esters form when organic
acids react with alcohols. In a reversible
reaction, ethanoic acid and methanol
produce methyl ethanoate (methyl acetate).
9.2 Substituted Hydrocarbons
Esters
Esters are used in many
processed foods to
produce fruit flavors.
Esters in roses and
other flowers have
distinctive odors that
attract insects.
9.2 Substituted Hydrocarbons
Assessment Questions
1. An alcohol is formed by replacing at least one
hydrogen in a hydrocarbon with a(n)
a.
b.
c.
d.
carboxyl group.
hydroxyl group.
amino group.
carbon group.
9.2 Substituted Hydrocarbons
Assessment Questions
1. An alcohol is formed by replacing at least one
hydrogen in a hydrocarbon with a(n)
a.
b.
c.
d.
carboxyl group.
hydroxyl group.
amino group.
carbon group.
ANS: B
9.2 Substituted Hydrocarbons
Assessment Questions
2. What are the products of the reaction between
chloroethane and sodium hydroxide?
a.
b.
c.
d.
ethanoic acid and sodium chloride
ethanol and sodium chloride
sodium ethanoate and chlorine
chloroethanol and sodium
9.2 Substituted Hydrocarbons
Assessment Questions
2. What are the products of the reaction between
chloroethane and sodium hydroxide?
a.
b.
c.
d.
ethanoic acid and sodium chloride
ethanol and sodium chloride
sodium ethanoate and chlorine
chloroethanol and sodium
ANS: B