Chemistry 22.2
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22.2
Unsaturated Hydrocarbons
Roach traps are baited with
pheromones, which roaches
produce to attract mates. The
structure of many pheromones
is based on unsaturated
hydrocarbons. You will study
two types of unsaturated
hydrocarbons—alkenes and
alkynes.
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22.2
Unsaturated Hydrocarbons
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Alkenes
Alkenes
What are the structural characteristics
of alkenes?
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22.2
Unsaturated Hydrocarbons
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Alkenes
At least one carbon-carbon bond in an
alkene is a double covalent bond. Other
bonds may be single carbon-carbon
bonds and carbon-hydrogen bonds.
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22.2
Unsaturated Hydrocarbons
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Alkenes
• Organic compounds that contain the
maximum number of hydrogen atoms per
carbon atom are called saturated
compounds.
• Compounds that contain double or triple
carbon-carbon bonds are called unsaturated
compounds.
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22.2
Unsaturated Hydrocarbons
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Alkenes
Alkenes are hydrocarbons that contain one or
more carbon-carbon double covalent bonds.
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22.2
Unsaturated Hydrocarbons
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Alkenes
Because rotation is restricted around the double
bond, atoms in ethene lie in one plane.
Ethene
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22.2
Unsaturated Hydrocarbons
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Alkynes
Alkynes
What are the structural characteristics
of alkynes?
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22.2
Unsaturated Hydrocarbons
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Alkynes
At least one carbon-carbon bond in an
alkyne is a triple covalent bond. Other
bonds may be single or double carboncarbon bonds and single carbonhydrogen bonds.
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22.2
Unsaturated Hydrocarbons
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Alkynes
• Hydrocarbons that contain one or more
carbon-carbon triple covalent bonds are called
alkynes.
• Straight-chain and branched-chain alkanes,
alkenes, and alkynes are aliphatic
hydrocarbons.
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22.2
Unsaturated Hydrocarbons
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Alkynes
The triple bond restricts rotation in an ethyne
molecule, which has a linear shape.
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22.2
Unsaturated Hydrocarbons
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Alkenes
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22.2 Section Quiz.
Assess students’ understanding
of the concepts in Section 22.2.
Continue to:
-or-
Launch:
Section Quiz
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22.2 Section Quiz.
1. Alkenes and alkynes are called unsaturated
compounds because they contain
a. single bonds only.
b. double or triple bonds.
c. oxygen atoms.
d. hydrogen atoms.
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22.2 Section Quiz.
2. What is the correct name for a compound with
a C-C-C=C-C carbon skeleton?
a. 3-pentyne
b. 2-pentene
c. 3-pentene
d. 4-pentene
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22.2 Section Quiz.
3. Which of the following substances is an
alkyne?
a. C6H12
b. C2H4
c. C2H2
d. C4H8
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END OF SHOW