section 20.1 saturated hydrocarbons 1.to understand the types of bonds formed by the carbon atom...
TRANSCRIPT
Section 20.1
Saturated Hydrocarbons
1. To understand the types of bonds formed by the carbon atom
2. To learn about the alkanes
3. To learn about structural isomers
4. To learn to draw structural formulas
5. To learn to name alkanes and substituted alkanes
6. To learn about the composition and uses of petroleum
7. To learn about the chemical reactions of alkanes
Objectives
Section 20.1
Saturated Hydrocarbons
Carbon Chemistry
• Carbon is unusual – Bonds strongly to itself – Forms long chains or rings
• Biomolecule – molecule that functions in maintaining and reproducing life
• Organic compounds – vast majority of carbon compounds – Exceptions – oxides and carbonates
Section 20.1
Saturated Hydrocarbons
A. Carbon Bonding
• When carbon has 4 atoms bound to it these atoms have a tetrahedral shape.
Section 20.1
Saturated Hydrocarbons
A. Carbon Bonding
Double bond
Triple bond • Sharing of 3 pairs of electrons
• Sharing of 2 pairs of electrons
Section 20.1
Saturated Hydrocarbons
B. Alkanes
• Hydrocarbons – compounds composed of carbon and hydrogen– Saturated – all carbon-carbon bonds are single bonds– Unsaturated – containing carbon-carbon multiple bonds
Section 20.1
Saturated Hydrocarbons
B. Alkanes
• Normal, straight-chain or unbranched hydrocarbons
• Contain strings or chains of carbon atoms – Representations
Section 20.1
Saturated Hydrocarbons
C. Structural Formulas and Isomerism
• Structural isomerism – occurs when 2 molecules have the same atoms but different bonds
Section 20.1
Saturated Hydrocarbons
D. Naming Alkanes
• The name for an alkane is based on Greek root with the suffix –ane.
Basic principles
Section 20.1
Saturated Hydrocarbons
D. Naming Alkanes
• For branched hydrocarbons use the longest continuous chain for the root name.
Basic principles
Section 20.1
Saturated Hydrocarbons
D. Naming Alkanes
• Alkanes missing one H atom can have another hydrocarbon attached at the missing H point.
Basic principles
Section 20.1
Saturated Hydrocarbons
D. Naming Alkanes
• Specify the names of substituents by numbering the C atoms starting at the end closest to the branching.
Basic principles
Section 20.1
Saturated Hydrocarbons
D. Naming Alkanes
• If a substituent occurs more than once use a prefix to show this.
Basic principles
2,3-dimethylpentane
Section 20.1
Saturated Hydrocarbons
E. Petroleum
• Petroleum – thick, dark liquid composed mostly of hydrocarbon compounds
• Natural gas – consists mostly of methane, usually associated with petroleum deposits
Section 20.1
Saturated Hydrocarbons
F. Reactions of Alkanes
• Combustion – reaction with oxygen
• Substitution – one or more H atoms are replaced with different atoms
Section 20.1
Saturated Hydrocarbons
F. Reactions of Alkanes
• Dehydrogenation – one or more H atoms are removed and the product is an unsaturated hydrocarbon
Section 20.2
Unsaturated Hydrocarbons
1. To learn to name hydrocarbons with double and triple bonds
2. To understand addition reactions
3. To learn about the aromatic hydrocarbons
4. To learn to name aromatic compounds
Objectives
Section 20.2
Unsaturated Hydrocarbons
A. Alkenes and Alkynes
• Alkenes – hydrocarbon containing carbon-carbon double bonds
– General formula CnH2n
• Alkynes – hydrocarbons containing carbon-carbon triple bonds
– General formula CnH2n - 2
Section 20.2
Unsaturated Hydrocarbons
• Addition reactions – new atoms form single bonds to the carbons formerly involved in a double or triple bond
– Hydrogenation – use H2 as the reactant to be added
Reactions of Alkenes
– Halogenation – addition of halogen atoms
• Polymerization – joining of many small molecules to form a large molecule
A. Alkenes and Alkynes
Section 20.2
Unsaturated Hydrocarbons
B. Aromatic Hydrocarbons
• Aromatic hydrocarbons – cyclic unsaturated hydrocarbons with strong aromas
Section 20.2
Unsaturated Hydrocarbons
B. Aromatic Hydrocarbons
• Benzene – simplest aromatic hydrocarbon
Section 20.2
Unsaturated Hydrocarbons
C. Naming Aromatic Compounds
• Monosubstituted benzenes –
use the substituent name as
a prefix of benzene
Section 20.2
Unsaturated Hydrocarbons
C. Naming Aromatic Compounds
• Disubstituted benzenes – use numbers to indicate the position of substituents and the substituent name as a prefix of benzene
Section 20.3
Introduction to Functional Groups and Alcohols
1. To learn the common functional groups in organic molecules
2. To learn about simple alcohols and how to name them
3. To learn about how some alcohols are made and used
Objectives
Section 20.3
Introduction to Functional Groups and Alcohols
A. Functional Groups • Functional group – additional atom or groups of atoms
(containing elements in addition to H and C) found on a mostly hydrocarbon molecule
Section 20.3
Introduction to Functional Groups and Alcohols
B. Alcohols
• All alcohols contain the –OH group.
Section 20.3
Introduction to Functional Groups and Alcohols
C. Properties and Uses of Alcohols
• Methanol – starting material for making acetic acid and many
adhesives, fibers and plastics – motor fuel
• Ethanol – Fermentation product
– Fuel additive used to make gasohol
Section 20.3
Introduction to Functional Groups and Alcohols
C. Properties and Uses of Alcohols
• Other alcohols
– Ethylene glycol – automotive antifreeze – Phenol – production of adhesives and plastics
Section 20.4
Additional Organic Compounds
1. To learn about aldehydes and ketones
2. To learn to name aldehydes and ketones
3. To learn about some common carboxylic acids and esters
4. To learn about some common polymers
Objectives
Section 20.4
Additional Organic Compounds
A. Aldehydes and Ketones
• Carbonyl group – carbon oxygen group found in both aldehydes and ketones
– Ketone – carbonyl group is bonded to two carbon atoms
Section 20.4
Additional Organic Compounds
A. Aldehydes and Ketones
– Aldehyde – carbonyl group always appears on the end of the hydrocarbon chain and has at least one H atom bonded to the carbonyl group
Section 20.4
Additional Organic Compounds
B. Naming Aldehydes and Ketones
• Aldehydes
– Use the parent alkane name. • Remove the e and replace it with al.
Section 20.4
Additional Organic Compounds
B. Naming Aldehydes and Ketones
• Ketones
– Use the parent alkane name. • Remove the e and replace it with one. • Use a number to indicate the position of the
carbonyl group in the hydrocarbon chain. – Select the number so that the carbonyl has the lowest
possible number.
Section 20.4
Additional Organic Compounds
C. Carboxylic Acids and Esters
• Carboxylic acids – contains the carboxyl group
– COOH
• General formula RCOOH • Weak acids in solution
Section 20.4
Additional Organic Compounds
C. Carboxylic Acids and Esters
• To name carboxylic acids
– Use the parent alkane name. • Remove the e and replace it with oic.
Section 20.4
Additional Organic Compounds
C. Carboxylic Acids and Esters
• Esters – a carboxylic acid reacts with an alcohol to form an ester and a water molecule
– General formula
Section 20.4
Additional Organic Compounds
C. Carboxylic Acids and Esters
• To name esters
– Use the alkyl name from the alcohol followed by the acid name, where the –ic ending is replaced by –ate.
isopropylethanoate
Section 20.4
Additional Organic Compounds
D. Polymers
• Polymers – large chainlike molecules made from many small molecules called monomers – Simplest polymer – polyethylene– Polyethylene results from addition polymerization.