Chapter 2: Alkanes and Cycloalkanes - PowerPoint PPT Presentation

1 / 13
About This Presentation
Title:

Chapter 2: Alkanes and Cycloalkanes

Description:

Low-molecular-weight alkanes (methane to butane) are gases at room temperature. ... Octane rating: The percent 2,2,4-trimethylpentane (isooctane) in a mixture of ... – PowerPoint PPT presentation

Number of Views:60
Avg rating:3.0/5.0
Slides: 14
Provided by: uclache
Category:

less

Transcript and Presenter's Notes

Title: Chapter 2: Alkanes and Cycloalkanes


1
Chapter 2 Alkanes and Cycloalkanes
  • Chem 30A
  • Lecture 8

2
Physical Properties of Alkanes
  • Intermolecular forces of attraction
  • ion-ion (Na and Cl- in NaCl)
  • ion-dipole (ions solvated in aqueous solution)
  • dipole-dipole and hydrogen bonding
  • dispersion forces (electrostatic attraction
    between temporary dipoles)

3
Physical Properties
  • Low-molecular-weight alkanes (methane to butane)
    are gases at room temperature.
  • Higher molecular-weight alkanes (pentane, decane,
    gasoline, and kerosene) are liquids at room
    temperature.
  • High-molecular-weight alkanes (paraffin wax) are
    semisolids or solids at room temperature.

4
Physical Properties
  • Constitutional isomers have different physical
    properties.

5
Oxidation of Alkanes
  • Oxidation is the basis for the use of alkanes as
    energy sources for heat and power.
  • heat of combustion The heat released when one
    mole of a substance in its standard state is
    oxidized to carbon dioxide and water.

6
Heat of Combustion
  • Heat of combustion for constitutional isomers

7
Heats of Combustion
  • For constitutional isomers kJ (kcal)/mol

8
Heat of Combustion
  • Strain in cycloalkane rings determined by
  • heats of combustion

9
Sources of Alkanes
  • Natural gas
  • 90-95 methane
  • Petroleum
  • gases (bp below 20C)
  • naphthas, including gasoline (bp 20 - 200C)
  • kerosene (bp 175 - 275C)
  • fuel oil (bp 250 - 400C)
  • lubricating oils (bp above 350C)
  • asphalt (residue after distillation)
  • Coal

10
Petroleum
  • Fractional distillation of petroleum.

11
Gasoline
  • Octane rating The percent 2,2,4-trimethylpentane
    (isooctane) in a mixture of isooctane and heptane
    that has equivalent antiknock properties.

12
Synthesis Gas
  • A mixture of carbon monoxide and hydrogen in
    varying proportions which depend on how it is
    produced.

13
Synthesis Gas
  • Synthesis gas is a feedstock for the industrial
    production of methanol and acetic acid.
  • It is likely that industrial routes to other
    organic chemicals from coal via methanol will
    also be developed.
Write a Comment
User Comments (0)
About PowerShow.com