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CHEM 121:
General Chemistry II
Dr. Wanda Oehrli (Early)

Welcome back!
“All the world is a laboratory to the
inquiring mind”
• Martin H. Fischer
• (1879 - 1962)
• German-American physician and ...
Today’s Agenda
•
•
•
•

Roll sheet, please sign and note your TEAM #
Introductions
Start Chapter 11
Syllabus
Grew up in DeKalb
Kalamazoo College & MSU

B.A. Chemistry, 1992

Ph.D. Chemistry, 1997
Ph.D. Research
• Optical Sensors
• Funded by the Air Force
• Benzene, Toluene, Zylene
(BTEX) are used to clean jet
engines...
NRC Postdoctoral Research Fellow
Center for Advanced Research in Biotechnology
and National Cancer Institute
1997-2004
Pro...
Teaching 2005-2008 & Ball
Horticultural
Kishwaukee
Beloit
Rock Valley
Elmhurst
Harper
Got Married
Flower seed
germination
2009- Present
MBA – DePaul
Consulting Work
Nanotechnology company in S. Dakota
Green Certification Company in CA
Investmen...
I want to get to know you!
• Please fill out the info sheet as
thoroughly as possible
• This information will help me get ...
Gen. Chem. Lab
• Lab begins next week! January 16!
– Lab Safety and Math Review

• No class of January 20 (MLK Week) & no
...
Office Hours
My office is Parmer 319
• M,W, F 10:30 -11:30 (meet in 310 if 319 is
occupied)
• Or by appointment (e-mail me...
Pre-Class Reading Assignment

Reading for Friday January 10:
Sections 11.1-11.2
There will be a Reading Quiz at
the beginn...
Chapter 11
Intermolecular Forces
A Molecular Comparison of Liquids
and Solids

15
A Molecular Comparison of Liquids
and Solids
• Converting a gas into a liquid or solid requires
the molecules to get close...
Intermolecular Forces
Intermolecular Forces
• The covalent bond holding a molecule together is an
intramolecular forces.
• The attraction betwee...
Intermolecular Forces
There are four types of intermolecular forces
(IMF) for covalent molecules:
•
•
•
•

London Dispersi...
Strength of IM Forces
•
•
•
•

London Dispersion Forces (LD)
2-10 kJ/mol
Dipole-Dipole (D/D)
Ion-Dipole (I/D, only in wate...
Polarity of Molecules
Dipole Moments of Polyatomic Molecules
Induced Dipoles or Instantaneous
Dipoles
Neutral molecules and atoms can induce
a charge in each other
London Dispersion Forces

The fluctuating charge distribution in an atom can give rise to an
instantaneous dipole moment.
...
London Dispersion Forces
• These forces are
present in all
molecules, whether
they are polar or
nonpolar.
• The tendency o...
Factors Affecting London Forces
• The strength of
dispersion forces tends
to increase with
increased molecular
weight.
• L...
Syllabus
• Go over syllabus with your “Team”
– Introduce yourselves
– Take a few minutes to read the syllabus
– Then, with...
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Jan8 2014 CHEM 121 Lecture Dominican University Wanda Oehrli

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Transcript of "Jan8 2014 CHEM 121 Lecture Dominican University Wanda Oehrli"

  1. 1. CHEM 121: General Chemistry II Dr. Wanda Oehrli (Early) Welcome back!
  2. 2. “All the world is a laboratory to the inquiring mind” • Martin H. Fischer • (1879 - 1962) • German-American physician and writer • An education in chemistry and science can be applied to a broad variety of problems.
  3. 3. Today’s Agenda • • • • Roll sheet, please sign and note your TEAM # Introductions Start Chapter 11 Syllabus
  4. 4. Grew up in DeKalb
  5. 5. Kalamazoo College & MSU B.A. Chemistry, 1992 Ph.D. Chemistry, 1997
  6. 6. Ph.D. Research • Optical Sensors • Funded by the Air Force • Benzene, Toluene, Zylene (BTEX) are used to clean jet engines • BTEX leach into ground water • Bioremediation
  7. 7. NRC Postdoctoral Research Fellow Center for Advanced Research in Biotechnology and National Cancer Institute 1997-2004 Protein Folding GroEL GroES How do heat shock proteins work? Biopharmaceutical Development of drugs for cancer based on antibodies and other biomolecules
  8. 8. Teaching 2005-2008 & Ball Horticultural Kishwaukee Beloit Rock Valley Elmhurst Harper Got Married Flower seed germination
  9. 9. 2009- Present MBA – DePaul Consulting Work Nanotechnology company in S. Dakota Green Certification Company in CA Investment Advisor Firm Internet Marketing Back to teaching
  10. 10. I want to get to know you! • Please fill out the info sheet as thoroughly as possible • This information will help me get to know you and shape the course for your needs
  11. 11. Gen. Chem. Lab • Lab begins next week! January 16! – Lab Safety and Math Review • No class of January 20 (MLK Week) & no lab that week • Lab resumes week following week
  12. 12. Office Hours My office is Parmer 319 • M,W, F 10:30 -11:30 (meet in 310 if 319 is occupied) • Or by appointment (e-mail me) • Office hours will be posted on the myDU page each week
  13. 13. Pre-Class Reading Assignment Reading for Friday January 10: Sections 11.1-11.2 There will be a Reading Quiz at the beginning of class on Friday!
  14. 14. Chapter 11 Intermolecular Forces
  15. 15. A Molecular Comparison of Liquids and Solids 15
  16. 16. A Molecular Comparison of Liquids and Solids • Converting a gas into a liquid or solid requires the molecules to get closer to each other: – cool or compress. • Converting a solid into a liquid or gas requires the molecules to move further apart: – heat or reduce pressure. • The forces holding solids and liquids together are called intermolecular forces.
  17. 17. Intermolecular Forces
  18. 18. Intermolecular Forces • The covalent bond holding a molecule together is an intramolecular forces. • The attraction between molecules is an intermolecular force. • Intermolecular forces are much weaker than intramolecular forces • (e.g. 16 kJ/mol vs. 431 kJ/mol for HCl). • Ex. Less energy is required to vaporize liquid HCl than to form an HCl bond • When a substance melts or boils the intermolecular forces are broken (not the covalent bonds). When a substance condenses intermolecular forces are formed.
  19. 19. Intermolecular Forces There are four types of intermolecular forces (IMF) for covalent molecules: • • • • London Dispersion Forces (LD) Dipole-Dipole (D/D) Hydrogen bonding (H-bond) Ion-Dipole (I/D, only in water solutions) We see evidence of these intermolecular forces as they affect the boiling point and melting point of compounds. – As IMF increase … bp and mp increase
  20. 20. Strength of IM Forces • • • • London Dispersion Forces (LD) 2-10 kJ/mol Dipole-Dipole (D/D) Ion-Dipole (I/D, only in water solutions) 15 kJ/mol Hydrogen bonding (H-bonding) 5-25 kJ/mol • First two are called van der Waals
  21. 21. Polarity of Molecules Dipole Moments of Polyatomic Molecules
  22. 22. Induced Dipoles or Instantaneous Dipoles Neutral molecules and atoms can induce a charge in each other
  23. 23. London Dispersion Forces The fluctuating charge distribution in an atom can give rise to an instantaneous dipole moment. When two atoms are close, their fluctuating dipole moments are correlated, leading to attraction.
  24. 24. London Dispersion Forces • These forces are present in all molecules, whether they are polar or nonpolar. • The tendency of an electron cloud to distort in this way is called polarizability.
  25. 25. Factors Affecting London Forces • The strength of dispersion forces tends to increase with increased molecular weight. • Larger atoms have larger electron clouds that are easier to polarize.
  26. 26. Syllabus • Go over syllabus with your “Team” – Introduce yourselves – Take a few minutes to read the syllabus – Then, with your team, come up with at least 3 questions you have about the class that are NOT answered on the syllabus – Write the questions down on a 4 x 6 card (one card per team) – I will collect the cards when you are done and put together a handout answering the questions.
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