1. Carey Chapter 2 – Hydrocarbon Frameworks : “Alkanes”
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2. Chemical Bonding
Figure 2.3 – Valence bond picture for H2
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3. 2.2-2.3 Chemical Bonding – Two Possibilities
Figure 2.5
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4. 2.4 Molecular orbitals by combining two atomic orbitals
Figure 2.6
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5. 2.5 Introduction to Alkanes – Methane, Ethane, Propane
Figure 2.7
CH CH3CH CH3CH2CH3
b.p oC oC oC
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6. 2.6 sp3 Hybridization and bonding in Methane
Figure 2.9
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7. 2.6 sp3 Hybridization and bonding in Methane
Figure 2.10
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8. 2.7 sp3 Hybridization and bonding in Ethane
Figure 2.11
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9. 2.8 Isomeric alkanes – the Butanes
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Structural Isomers
C4H10 n-butane
C4H10 isobutane
Higher alkanes – the C5H12 isomers
C5H12
n-pentane
C5H12
isopentane
C5H12
neopentane

10. 2.10 Higher alkanes – diversity
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11. Careful with drawing chains!
All the same compound!
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12. 2.11-2.12 Alkane nomenclature - Need to know up to C-12
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13. 2.11-2.12 Alkane nomenclature e.g. 2,3-dimethylheptane
IUPAC Rules:
Find the longest continuous carbon chain
Identify substituent groups attached to the chain
Number the chain so as to keep numbers small
Write the name in the following format:
Numerical location - [substituent(s)][parent alkane]
e.g. 2,3-dimethylheptane
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14. 2.12 IUPAC Rules and how to apply them
Hexane (IUPAC); n-hexane (common)
Longest chain - hexane
substituent - methyl
position on chain - 2
2-methylhexane not 5-methylhexane
2,4-dimethylheptane
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15. Replace -ane ending with -yl
2.13 Alkyl groups - Classes
Replace -ane ending with -yl
primary (1o) secondary (2o) tertiary (3o)
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16. Replace -ane ending with -yl
2.13 Alkyl groups - Common
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Replace -ane ending with -yl
propyl group isopropyl group t-Butyl group (1-methylethyl) (1,1-dimethylethyl)

17. 2.14 Highly branched alkanes
4-ethyloctane
4-ethyl-3-methyloctane
4-ethyl-3,5-dimethyloctane
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18. 2-ethyl-1,1-dimethylcyclopentane
2.15 Cycloalkanes
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1,1,3-trimethylcyclohexane
2-ethyl-1,1-dimethylcyclopentane
(notice the “di” is not involved in the alphabetization)
(1,1-dimethylethyl)cycloheptane

19. 2.16 Sources of alkanes and cycloalkanes
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Figure 2.12

20. 2.17 Physical properties
Figure 2.15
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21. 2.17 Physical properties – branched alkanes
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Figure 2.16

22. 2.18 Chemical properties of Alkanes
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Alkane properties:
Generally very insoluble in water (“greasy” or “oily”)
Individual molecules interact via van der Waals forces
These intermolecular forces decrease with branching
Alkanes may be combusted in oxygen:
e.g. CH4 + 2O2 CO2 + 2H2O DH = kcal
i.e combustion of hydrocarbons releases energy

23. 2.18 Heats of combustion – Figure 2.17
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24. 2.19 Oxidation-Reduction in Organic Chemistry
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25. 2.20 sp2 Hybridization in ethylene
Figure 2.18
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26. 2.20 sp2 Hybridization in ethylene
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Figure 2.19

27. 2.20 sp2 Hybridization in ethylene
Figure 2.20
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28. 2.21 sp Hybridization in acetylene
Figure 2.22
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29. 2.21 sp Hybridization in acetylene
Figure 2.21
Figure 2.23
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