che 240 unit 1 structure and stereochemistry of alkanes chapter two n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
CHE-240 Unit 1 Structure and Stereochemistry of Alkanes CHAPTER TWO PowerPoint Presentation
Download Presentation
CHE-240 Unit 1 Structure and Stereochemistry of Alkanes CHAPTER TWO

Loading in 2 Seconds...

play fullscreen
1 / 23

CHE-240 Unit 1 Structure and Stereochemistry of Alkanes CHAPTER TWO - PowerPoint PPT Presentation


  • 119 Views
  • Uploaded on

CHE-240 Unit 1 Structure and Stereochemistry of Alkanes CHAPTER TWO. Terrence P. Sherlock Burlington County College 2004. =>. Multiple Bonds. A double bond (2 pairs of shared electrons) consists of a sigma bond and a pi bond.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'CHE-240 Unit 1 Structure and Stereochemistry of Alkanes CHAPTER TWO' - lane


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
che 240 unit 1 structure and stereochemistry of alkanes chapter two

CHE-240Unit 1Structure and Stereochemistry of AlkanesCHAPTER TWO

Terrence P. Sherlock

Burlington County College

2004

multiple bonds

=>

Multiple Bonds
  • A double bond (2 pairs of shared electrons) consists of a sigma bond and a pi bond.
  • A triple bond (3 pairs of shared electrons) consists of a sigma bond and two pi bonds.

Chapter 2

molecular shapes
Molecular Shapes
  • Bond angles cannot be explained with simple s and p orbitals. Use VSEPR theory.
  • Hybridized orbitals are lower in energy because electron pairs are farther apart.
  • Hybridization is LCAO within one atom, just prior to bonding. =>

Chapter 2

sp hybrid orbitals

=>

sp Hybrid Orbitals
  • 2 VSEPR pairs
  • Linear electron pair geometry
  • 180° bond angle

Chapter 2

sp 2 hybrid orbitals

=>

sp2 Hybrid Orbitals
  • 3 VSEPR pairs
  • Trigonal planar e- pair geometry
  • 120° bond angle

Chapter 2

sp 3 hybrid orbitals

=>

sp3 Hybrid Orbitals
  • 4 VSEPR pairs
  • Tetrahedral e- pair geometry
  • 109.5° bond angle

Chapter 2

sample problems

=>

Sample Problems
  • Predict the hybridization, geometry, and bond angle for each atom in the following molecules:
  • Caution! You must start with a good Lewis structure!
  • NH2NH2
  • CH3-CC-CHO

Chapter 2

bond dipole moments
are due to differences in electronegativity.

depend on the amount of charge and distance of separation.

In debyes,

 = 4.8 x (electron charge) x d(angstroms)

=>

Bond Dipole Moments

Chapter 2

molecular dipole moments

=>

Molecular Dipole Moments
  • Depend on bond polarity and bond angles.
  • Vector sum of the bond dipole moments.
  • Lone pairs of electrons contribute to the dipole moment.

Chapter 2

intermolecular forces
Intermolecular Forces
  • Strength of attractions between molecules influence m.p., b.p., and solubility; esp. for solids and liquids.
  • Classification depends on structure.
    • Dipole-dipole interactions
    • London dispersions
    • Hydrogen bonding =>

Chapter 2

dipole dipole forces
Dipole-Dipole Forces
  • Between polar molecules
  • Positive end of one molecule aligns with negative end of another molecule.
  • Lower energy than repulsions, so net force is attractive.
  • Larger dipoles cause higher boiling points and higher heats of vaporization. =>

Chapter 2

dipole dipole
Dipole-Dipole

=>

Chapter 2

london dispersions

=>

London Dispersions
  • Between nonpolar molecules
  • Temporary dipole-dipole interactions
  • Larger atoms are more polarizable.
  • Branching lowers b.p. because of decreased surface contact between molecules.

Chapter 2

dispersions
Dispersions

=>

Chapter 2

hydrogen bonding
Hydrogen Bonding
  • Strong dipole-dipole attraction
  • Organic molecule must have N-H or O-H.
  • The hydrogen from one molecule is strongly attracted to a lone pair of electrons on the other molecule.
  • O-H more polar than N-H, so stronger hydrogen bonding =>

Chapter 2

h bonds
H Bonds

=>

Chapter 2

solubility
Solubility
  • Like dissolves like
  • Polar solutes dissolve in polar solvents.
  • Nonpolar solutes dissolve in nonpolar solvents.
  • Molecules with similar intermolecular forces will mix freely. =>

Chapter 2

hydrocarbons
Hydrocarbons
  • Alkane: single bonds, sp3 carbons
  • Cycloalkane: carbons form a ring
  • Alkene: double bond, sp2 carbons
  • Cycloalkene: double bond in ring
  • Alkyne: triple bond, sp carbons
  • Aromatic: contains a benzene ring =>

Chapter 2

compounds containing oxygen

=>

Compounds Containing Oxygen
  • Alcohol: R-OH
  • Ether: R-O-R'
  • Aldehyde: RCHO
  • Ketone: RCOR'

Chapter 2

carboxylic acids and their derivatives

=>

Carboxylic Acids and Their Derivatives
  • Carboxylic Acid: RCOOH
  • Acid Chloride: RCOCl
  • Ester: RCOOR'
  • Amide: RCONH2

Chapter 2

compounds containing nitrogen

=>

Compounds Containing Nitrogen
  • Amines: RNH2, RNHR', or R3N
  • Amides: RCONH2, RCONHR, RCONR2
  • Nitrile: RCN

Chapter 2

slide23

POWER POINT IMAGES FROM “ORGANIC CHEMISTRY, 5TH EDITION”L.G. WADEALL MATERIALS USED WITH PERMISSION OF AUTHORPRESENTATION ADAPTED FOR BURLINGTON COUNTY COLLEGEORGANIC CHEMISTRY COURSEBY:ANNALICIA POEHLER STEFANIE LAYMAN CALY MARTIN

Chapter 2