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1. (18 pts) Draw six (6) different isomers with the empirical formula C9H20.
NAME all six isomers using only IUPAC nomenclature.
ANSWER
2. (14 pts) For each of the following, circle all correct answers. Note that
a penalty of -1/2 will be assessed for each extra answer.
(a) Circle the strongest acid.
ANSWER
(b) Circle all molecules that have at least one atom with sp hybridization.
ANSWER
(c) Circle the electronic configuration for Na+.
ANSWER
(d) Circle the syn rotamer of ethane.
ANSWER
(e) Circle the molecule with the largest dipole.
ANSWER
(f) Circle the molecule expected to have the highest boiling point.
ANSWER
(g) Circle the orbital that best describes the shape of a sp3 hybrid orbital.
ANSWER
(h) Circle the molecule expected to have the largest Ka upon reaction with a
strong base.
ANSWER
(i) Circle all molecules that have a prefix of pent-.
ANSWER
(j) Circle all molecules that are resonance stabilized.
ANSWER
3. (10 pts, 6,2,2) When comparing the reaction of formic acid with NaOH and
methanol with NaOH (both structures are shown), the
equilibrium concentration of the conjugate base of formic
acid is greater than the equilibrium concentration of the
conjugate base of methanol.
(a) Explain why the concentration of the conjugate base from methanol is lower
than from formic acid.
(b) When comparing the two reactions, how does the greater concentration of
conjugate base from formic acid influence Ka?
(c) Which is likely to be more acidic? formic acid or methanol?
ANSWER
4. (12 pts) Draw the more stable rotamer of 1,2-difluoroethane in both Newman
projection, and as a sawhorse diagram, on the provided figures.
Note that in both cases, bonds are drawn to one atom and not the
other. You must draw in all atoms as well as the three bonds that
are missing - for the more stable rotamer.
ANSWER
5. (10 pts) Briefly explain why the C-F bond in fluoromethane is stronger than
the C-Cl bond in chloromethane.
ANSWER
6. (14 pts, 2, 12)
(a) Calculate the formal charge for any atom for which the charge is not
zero. SHOW YOUR WORK
ANSWER
(b) Draw all resonance structures for this molecule.
ANSWER
7. (10 pts, 3, 7) Allene is an interesting molecule with the structure
H2C=C=CH2.
(a) Give the hybridization for all three carbon atoms.
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ANSWER
(b) Draw a diagram that indicates the relative position of any and all sigma
bonds and pi bonds.
ANSWER
8. (12 pts, 4, 3, 5) (a) Draw the product expected when boron trifluoride
(BF3) reacts with water (HOH).
ANSWER
(b) Is AlCl3 a Lewis acid? Why or why not?
ANSWER
(c) If BF3 is a Lewis acid, and I say that it reacts with chloromethane to
form an ate complex - draw that complex using Lewis electron dot
structures.
ANSWER
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