9.2 substituted hydrocarbons the electric drill can be used to drill holes, tighten a screw, or sand...
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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.
hole saw bit
Forstner drill bit
Phillips screwdriver bit
twist drill bit
drum sander
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A hydrocarbon in which one or more hydrogen atoms have been replaced by an atom or group of atoms is a substituted hydrocarbon.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
Graph the data below, plotting boiling point vs. number of chlorine atoms. Draw a smooth curve connecting the points.
Exploring Boiling Points of Chlorocarbons
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
What functional groups are found in alcohols?
Alcohols
The functional group in an alcohol is a hydroxyl group, –OH.
9.2 Substituted Hydrocarbons
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.
Alcohols
9.2 Substituted Hydrocarbons
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.
Alcohols
9.2 Substituted Hydrocarbons
What functional groups are found in organic acids and organic bases?
Organic Acids and 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
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).
Organic Acids and Bases
9.2 Substituted Hydrocarbons
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.
Organic Acids and Bases
9.2 Substituted Hydrocarbons
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.
Organic Acids and Bases
9.2 Substituted Hydrocarbons
How are esters formed?
Esters
Esters form when organic acids react with alcohols.
9.2 Substituted Hydrocarbons
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).
Esters
9.2 Substituted Hydrocarbons
Esters are used in many processed foods to produce fruit flavors.
Esters in roses and other flowers have distinctive odors that attract insects.
Esters
9.2 Substituted Hydrocarbons
Assessment Questions
1. An alcohol is formed by replacing at least one hydrogen in a hydrocarbon with a(n) a. carboxyl group.
b. hydroxyl group.
c. amino group.
d. 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. carboxyl group.
b. hydroxyl group.
c. amino group.
d. carbon group.
ANS: B
9.2 Substituted Hydrocarbons
Assessment Questions
2. What are the products of the reaction between chloroethane and sodium hydroxide?a. ethanoic acid and sodium chlorideb. ethanol and sodium chloridec. sodium ethanoate and chlorined. chloroethanol and sodium
9.2 Substituted Hydrocarbons
Assessment Questions
2. What are the products of the reaction between chloroethane and sodium hydroxide?a. ethanoic acid and sodium chlorideb. ethanol and sodium chloridec. sodium ethanoate and chlorined. chloroethanol and sodium
ANS: B