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HYDROCARBONS
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http://www.youtube.com/watch?v=mAjrnZ-znkY
HYDROCARBON BONDING
HYDROCARBONS
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– A hydrocarbon is a compound consisting of only hydrogen and carbon. – The carbon to carbon can be single, double, or triple bonds. – The bonds are always nonpolar. – Alkanes are hydrocarbons with only single bonds. • Each successive compound differs from the one before it only by a CH2 – As the number of Carbons increase so does the MP/BP – As the number of Carbons increase so does structural isomers
HYDROCARBON BONDING
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(A) straight (B) branched (C) in a closed ring
single (A) double (B) triple (C) Each carbon atom has four dashes, which represent four bonding pairs of electrons, satisfying the octet rule.
1
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First Ten Hydrocarbons Name
2 ALKANES CnH2n+2
3 4 5 6
Methane
Number of Molecular Carbon Atoms Formula CH4 1 CH4
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Condensed Structural Formula
LEARN IT, LOVE IT!
Ethane
2
C2H6
CH3CH3
Propane
3
C3H8
CH3CH2CH3
Butane
4
C4H10
CH3CH2CH2CH3
Pentane
5
C5H12
CH3CH2CH2CH2CH3
Hexane
6
C6H14
CH3CH2CH2CH2CH2CH3
Heptane
7
C7H16
CH3CH2CH2CH2CH2CH2CH3
Octane
8
C8H18
CH3CH2CH2CH2CH2CH2CH2CH3
Nonane
9
C9H20
CH3CH2CH2CH2CH2CH2CH2CH2CH3
Decane
10
C10H22
CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3
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H
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#1 METHANE
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S
#2 ETHANE
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H H H H
H C H H
H
C C C C H H H H H
Methane CH4
Butane C4H10
Methane is Tetrahedral
H
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 634
#2 ETHANE
H
H
C
C
H
H
H
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 635
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#3 PROPANE
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Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 635
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#3 PROPANE
H
H
H
H
C
C
C
H
H
H
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Structure of Propane
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H
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 635
#4 BUTANE
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Structure of Butane
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Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 635
#5 PENTANE
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S Hydrocarbons (alkanes) SINGLE BOND
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ALKANE PROPERTIES Name
Number of Molecular Melting Boiling Carbon Atoms Formula Point, oC Point, oC
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# of Isomers
Methane
1
CH4
-182.5
-161.5
0
Ethane
2
C2H6
-183.2
-88.6
0
n-Propane
3
C3H8
-187.7
-42.1
0
n-Butane
4
C4H10
-138.3
-0.5
2
n-Pentane
5
C5H12
-129.7
36.1
3
n-Hexane
6
C6H14
-95.3
68.7
5
n-Heptane
7
C7H16
-90.6
98.4
9
n-Octane
8
C8H18
-56.8
125.7
18
n-Nonane
9
C9H20
-53.6
150.8
35
n-Decane
10
C10H22
-29.7
174.0
75
butane
H H H H H
NAMING ALKANES
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1. Find the longest continuous chain of carbon atoms in the molecule 2. Start numbering the chain at the carbon nearest the first branching point constituents have the lowest #s possible) 3. Name and number the constituents Hydrocarbon groups that are attached to the longest continuous chain and named using the parent name, changing the –ane suffix to –yl. 4. Write out the name of the molecule
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Isomers of Pentane
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C C C C H H H H H
Isomers of Butane
C4H10
H HH H C H H
C C C
H
H H H
methyl propane or isobutane Timberlake, Chemistry 7th Edition, page 383
STRUCTURAL ISOMERS
Timberlake, Chemistry 7th Edition, page 385
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• Carbon can make 4 covalent bonds – There are more carbon-based compounds present on earth than the total of all compounds lacking carbon – Compounds that have the same molecular formula, but different structures (arrangements of the atoms) are called isomers. • Example: Isomers of C4H10 – Butane:
CH3 CH2 CH2 CH3
– Isobutane:
CH3 CH
Structural Isomers All have formula C5H12
NAMING ALKANES
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• Identify the longest continuous chain. • The locations or other groups of atoms attached to the longest chain are identified and numbered by counting from the end of the molecule which keeps the numbering system as low as possible.
CH3
CH3
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METHYL GROUPS (R)
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H H C H
H
H H
C C C C H H H H H
Methane CH4
H C
?
Butane C4H10
H
H ? R
H H H H
C H
R
H
C C C C H H H H H
Methyl -CH3
C C C 1 6
52
43
Butyl -C4H9
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H H CH3 H
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H H H H
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CH3 CH3
H H C H 3 4
C C C C C C
H C H 25
2,4,5 trimethyl 3ethyl octane
CH3
H C H 16
H 3, 3 dimethyl hexane or
Lowest sum of numbers is correct
4, 4 dimethyl hexane
2, 5 dimethyl 3,3diethyl nonane
ALKENES AND AKYNES
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Hydrocarbons Number of Alkanes Carbon Atoms CnH2n + 2
Alkenes CnH2n
Alkynes CnH2n-2
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1
CH4
Methane
2
C2H6
Ethane
C2H4
Ethene
C2H2
Ethyne
3
C3H8
Propane
C3H6
Propene
C3H4
Propyne
Butane
C4H8
Butene
C4H6
Butyne
Pentene
C5H8
Pentyne
4
C4H10
5
C5H12
Pentane
C5H10
6
C6H14
Hexane
C6H12
Hexene
C6H10
Hexyne
Heptane
C7H14
Heptene
C7H12
Heptyne
Octene
C8H14
Octyne
7
C7H16
8
C8H18
Octane
C8H18
9
C9H20
Nonane
C9H18
Nonene
C9H16
Nonyne
C10H20
Decene
C10H18
Decyne
10
C10H22 Decane
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ALKENES AND ALKYNES
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• Alkenes and Alkynes – Alkenes are hydrocarbons with at least one double carbon to carbon bond. • To show the presence of the double bond, the –ane suffix from the alkane name is changed to –ene. – The alkenes are unsaturated with respect to hydrogen • This means it does not have the maximum number of hydrogen atoms as it would if it were an alkane (a saturated hydrocarbon).
ALKYNES
ALKENES
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CnH2n
S
S
S
S
(CnH2n-2)
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S
S
S
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H H H H H
C C C C H
C C C C H 1
Butane C4H10
H
2
3
H
H H H H
• Ethylene is the gas that ripens fruit, and a ripe fruit emits the gas, which will act on unripe fruit. • A ripe tomato placed in a sealed bag with green tomatoes will help ripen them.
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H H H
H
4
H H but(1)ene
1-butene n-butene
H
H H H
C
C C C H
H
H H
Butene Butane C4H8
1
2
3
4
2-butene
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DNA damage
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DO YOU CARE
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NAMING ALKENES/ ALKYNESS
Guanine
+ HO OH
8-Hydroxyguanine
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– Naming is similar to naming alkanes except: • The longest continuous chain must contain the double bond. • The base name now ends in –ene. • The carbons are numbered so as to keep the number for the double bond as low as possible. • The base name is given a number which identifies the location of the double bond. – An alkyne is a hydrocarbon with at least one carbon to carbon triple bond. – Naming an alkyne is similar to the alkenes, except the base name ends in –yne.
The most highly mutagenic lesions identified
FUNCTIONAL GROUPS S
ALCOHOLS
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– Alkenes can also add to each other in an addition reaction to form long chains of carbon compounds. • this is called polymerization – The atom or group of atoms that are added to the hydrocarbon are called functional groups. • Functional groups usually have multiple bonds or lone pairs of electrons that make them very reactive. FREE RADICALS?????
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Alcohols S – An alcohol has a hydrogen replaced by a hydroxyl (-OH) group. – The name of the hydrocarbon that was substituted determines the name of the alcohol. – The alcohol is named using the hydrocarbon name and adding the suffix –ol. • If methane is substituted with an OH group it becomes methanol • If a pentane group is substituted with an OH group it is pentanol. • For alcohols with more than two carbon atoms we need the number the chain so as to keep the alcohol group as low as possible.
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Naming Functional Groups
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