mccord ch301

exam 3

11/5


Where do I go for Exam 3 ?

Monday • 11/5 • 7:30 - 9pm


9:30 Class

Room Assignments:

last names A - Mi in BUR 106

last names Mo - Z in JES A121A

Please make SURE you go to the right room!



11:00 Class

Room Assignments:

last names A - Mi in UTC 2.112A

last names Mo - Z in UTC 2.102A WCH 1.120

Please make SURE you go to the right room! Notice the obvious room change for Mo - Z students!

What we provide on Exams We will provide all students with:

  • copy of the exam
  • an answer sheet - aka: bubblesheet
  • a Periodic Table Handout sheet
  • scratch paper if needed

Note that the periodic table handout is available on the gchem site in the appendix under "Exam Preparation". Here is a direct link to the Periodic Table Handout for Exam 1.

Coverage: Exam 3 covers all the material that was covered on LE's 19-24 and HW's 08-12. The exam will cover the rest of Chapter 4 (Bonding) and all of Chapter 5 (IMFs) from the gchem site.

Questions: The exam has exactly 25 multiple choice questions. All the questions have equal weights of 4 points each. We will only grade you by what is bubbled in on the answer sheet. We will not look at your exam copy for answers, nor consider them in any way. Bubble carefully and correctly.

Bring the Following to the Exam

  • a pencil(s) - mechanical or wood
  • scanner only reads pencil - no ink!
  • bring eraser if you are prone to mistakes
  • we provide the rest - see top of page

NO calculators on this exam!

DO NOT bring...

  • ink pens
  • ANY type of calculator!
  • electronic devices - including earbuds, etc...
  • smart watches - put away that Apple Watch!
  • small creatures - or large... no creatures

VSEPR Theory

Empirical. Shapes are predicted via "common sense" about electron regions repulsing each other.


Dr. McCord's VSEPR Help Site - a mini review site with all things VSEPR and a little VB to boot.

VB Theory

The geometries needed for compounds are made by combining atomic orbitals into hybrid orbitals with the corresponding geometries. Sigma and pi bonding are introduced and are a key component of this bonding theory. All hybridizations are localized on the central atoms.

MO Theory

All of the atomic orbitals for the entire set of atoms in the molecule are used to create a new set of molecular orbitals. MO theory is much more "whole-istic" meaning it includes all the nuclei and electrons to make molecular orbitals. The sigma and pi bonding concept is still in place, but antibonding orbitals are introduced as well.

Intermolecular Forces (IMFs)

Intermolecular forces are the forces that are between molecules. They are the forces that hold liquids and solids together - collectively known as cohesive forces.

dipole-dipole

All polar molecules have dipole-dipole forces of attraction. All the partial positive and negative charges pull the molecules together.

H bonding

A special case version of dipole-dipole that is much stronger than "plain" dipole-dipole. A partially positive H must be covalently bonded to a nitrogen, oxygen, or fluorine atom in order to have H-bonding.

dispersion forces

All molecules have dispersion forces. For non-polar molecules, dispersion forces are the only IMFs present. Dispersion forces are the weakest of the three forces when compared one to one in small molecules. However, dispersion forces scale with molecular size (surface area actually). So all large molecules (and atoms) tend to have large dispersion forces - so much so that all very large molecules are solids.

Learning Outcomes for Bonding

Students will be able to...

  1. Identify metals and non-metals, and predict the types of compounds (ionic/covalent) that will form from different elements.
  2. Distinguish between molecules, ions, and atoms.
  3. Predict the anion or cation that a main-group element is likely to form.
  4. Relate Coulomb’s law to ionic radii, ionic charge, and lattice energy.
  5. Describe the distance dependence of the potential energy of a covalent bond.
  6. Predict and explain relative bond strength and lengths in a compound.
  7. Name and write formulas for covalent compounds.
  8. Interpret line drawings of chemical compounds with implicit hydrogens, carbons, and lone pairs.
  9. Rank the polarity of covalent bonds based on relative electronegativity.
  10. Define dipole moment and identify polar bonds.
  11. Draw the best Lewis structure (including any resonance structures) for a molecule or polyatomic ion.
  12. Apply formal charges to structures and use them to predict the most likely structure.
  13. Recognize and apply exceptions to the octet rule.
  14. Apply the VSEPR model to determine a molecule's electronic and molecular geometry based on its Lewis dot structure.
  15. Assess if a molecule is polar based on polar bonds and its molecular geometry.
  16. Identify the orbital hybridization for any atom in a given molecule using the VB model.
  17. Describe the type of bond (e.g. sigma, pi) and the atomic orbitals that are associated with the bond using the VB model.
  18. Differentiate between localized and delocalized electrons within a structure.
  19. Diagram orbital hybridization using orbital notation.
  20. Recognize that Molecular Orbital (MO) theory is used to determine the energy of the electron in a molecule as well as its geometry.
  21. Differentiate between constructive interference and destructive interference of atomic orbitals.
  22. Construct and fully interpret a MO diagram, including identifying the bond order, the lowest energy electronic excitation energy (HOMO-LUMO gap), and the magnetism (paramagnetic or diamagnetic) for a compound.

Learning Outcomes for IMFs

Students will be able to...

  1. Define the three major intermolecular forces (IMFs) that can exist in condensed phases: dipole-dipole, hydrogen bonding, and dispersion.
  2. Predict the types of IMFs that a compound can exhibit based on its structure.
  3. Using bonding theories and IMFs, predict the chemical and physical properties of organic materials.
  4. Explain how size, shape and polarizability affect the magnitude of dispersion forces.
  5. Relate the IMFs of a compound to liquid properties such as boiling point, vapor pressure, viscosity, and surface tension.
  6. Explain how liquid properties vary with temperature.
  7. Fully describe (atomic arrangement/microscopic view) and visually depict the four types of solids (covalent, ionic, metallic, molecular).
  8. Summarize how the macroscopic properties of solids (e.g. melting point, hardness, conductivity) can be explained by the microscopic model of solids.
  9. Use physical data to deduce the type of bonding within solids.