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Carey Chapter 2 Hydrocarbon Frameworks Alkanes Hydrocarbons - - PowerPoint PPT Presentation
Carey Chapter 2 Hydrocarbon Frameworks Alkanes Hydrocarbons - - PowerPoint PPT Presentation
Carey Chapter 2 Hydrocarbon Frameworks Alkanes Hydrocarbons Hydrocarbons Hydrocarbons Aliphatic Aromatic Aliphatic Aromatic Aliphatic Aromatic Alkanes Alkanes Alkenes Alkenes Alkynes Alkynes Alkanes Alkenes Alkynes
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SLIDE 3
2.2-2.3 Chemical Bonding – Two Possibilities Figure 2.5
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2.4 Molecular orbitals by combining two atomic orbitals Figure 2.6
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2.5 Introduction to Alkanes – Methane, Ethane, Propane
Figure 2.7
CH4 CH3CH3 CH3CH2CH3 b.p. -160 oC
- 89 oC
- 42 oC
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2.6 sp3 Hybridization and bonding in Methane
Figure 2.9
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2.6 sp3 Hybridization and bonding in Methane
Figure 2.10
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2.7 sp3 Hybridization and bonding in Ethane
Figure 2.11
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2.8 Isomeric alkanes – the Butanes Structural Isomers C5H12 neopentane C4H10 isobutane C5H12 n-pentane C5H12 isopentane C4H10 n-butane 2.9-2.10 Higher alkanes – the C5H12 isomers
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2.10 Higher alkanes – diversity
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Careful with drawing chains!
CH3CHCH2CH3 CH3 CH3CHCH2CH3 CH3 CH3CH2CHCH3 CH3 CH3CH2CHCH3 CH3 CH2CH2CH3 CH3 CH3
All the same compound
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2.11-2.12 Alkane nomenclature Need to know up to C-12
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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 2.11-2.12 Alkane nomenclature
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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 3,4-dimethylheptane
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2.13 Alkyl groups Replace -ane ending with -yl
H C H C C C H C C C C C
primary (1o) secondary (2o) tertiary (3o) propyl group isopropyl group t-Butyl group 1-methylethyl 1,1-dimethylethyl
CH3 C CH3 H3C C H H H C H H C H H CH3CH2CH2 CH CH3 CH3 (CH3)2CH (CH3)3C
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2.14 Highly branched alkanes 4-ethyloctane 4-ethyl-3-methyloctane 4-ethyl-3,5-dimethyloctane
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2.15 Cycloalkanes
1,1,3-trimethylcyclohexane C(CH3)3 (1,1-dimethylethyl)cycloheptane 2-ethyl-1,1- dimethylcyclopentane (notice the “di” is not involved in the alphabetization)
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2.16 Sources of alkanes and cycloalkanes Figure 2.12
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2.17 Physical properties Figure 2.15
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2.17 Physical properties – branched alkanes Figure 2.16
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2.18 Chemical properties of Alkanes 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 ∆H = - 213 kcal i.e combustion of hydrocarbons releases energy
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2.18 Heats of combustion – Figure 2.17
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2.19 Oxidation-Reduction in Organic Chemistry
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C C H H H H
2.20 sp2 Hybridization in ethylene Figure 2.18
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2.20 sp2 Hybridization in ethylene Figure 2.19
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2.20 sp2 Hybridization in ethylene Figure 2.20
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2.21 sp Hybridization in ethylene Figure 2.21
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2.21 sp Hybridization in acetylene Figure 2.22
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