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Chemistry 1201 Section 4
Spring 1999
Professor Russo
Exam #7
Type of exam: Take-home. You can work with anyone on this exam, including me! You
should know how to do these problems, though. You will probably see similar problems again.
Due: Tuesday, April 13, at the beginning of class.
130 points. After this exam, you will have had 700 total points. If you have been perfect,
you can even stop taking exams!
Show your work neatly. We will not grade papers that just show an answer, nor can we
assign partial credit if we don't see the work.
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Question #1. (BLB 8.85 a) Compute the isomerization energy for the conversion of ethanol
to dimethylether. Express your answer in kJ/mol.
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isomerization energy, kJ/mol
Question #2. Draw three-dimensional representations of ethanol and dimethylether.
Chem 1201 Sec. 4
Exam #7
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Question #3. Bring “toothpick and jelly bean” models of the molecules in Question #2. Bring
them to class on the day this assignment is due. We'll grade immediately and you can eat your
molecules! You can also build these models out of a real molecular model set, which you will
need next year anyhow. I can also accept models made from pipecleaners, beads, beans, etc.
Question #4. (BLB 8.85b) Compute the isomerization energy for the conversion of ethylene
oxide to acetaldehyde. Express the answer in kJ/mol.
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Answer here
Question #5. (BLB 8.80) The Lewis structure shown in the book for this problem is
incorrect. Fix it.
Chem 1201 Sec. 4
Exam #7
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Question #6. (BLB 8.58c) Estimate the energy change (OK, it’s actually an enthalpy change)
for the decomposition of nitrogen chloride into nitrogen gas plus chlorine gas. Express your
answer in kJ per mol of nitrogen trichloride decomposed.
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decomposition enthalpy, kJ/mol
Question #7. Draw the Lewis dot structure for nitrogen chloride. Is the molecule polar?
Question #8. (BLB 2.38) OK—it’s time to do a little nomenclature, though it is an odious
task. Write formulae for these compounds.
a) Magnesium nitrate is:
b) Sodium carbonate is:
c) Barium hydroxide is:
d) Ammonium phosphate is:
e) Mercury (II) chlorate is:
Chem 1201 Sec. 4
Exam #7
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Question 9. (BLB 2.43) Name these ionic compounds
a) AlF3 = _________________________________________
b) Fe(OH)2 = _________________________________________
c) Ba(ClO4)2 = _________________________________________
c) Cr2(CO3)3 = _________________________________________
Question 10. (BLB 3.4) Balance these reactions.
a) _______PCl5 + _______H2O  _______H3PO4 + _______HCl
b) _______C5H10O2 + _______O2  _______CO2 + _______H2O
c) _______Mg3N2 + _______H2O  _______Mg(OH)2 + _______NH3
Question 11. We just had a seminar in the department by a famous professor named Luigi
Marzilli from Emory University in Atlanta. He studies the how the chemotherapy drug,
cisplatin, interacts with DNA. Compute the formula weight of cisplatin, PtCl2(NH3)2. How
many hydrogen atoms are there in 33.4 mg of cisplatin? Express your answer as an absolute
number and in millimoles (mmol). One of these is way more convenient than the other.
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hydrogen atoms in actual numbers
Chem 1201 Sec. 4
Exam #7
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hydrogen atoms in mmol
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Question 12. (BLB 3.34) Calculate the number of molecules present in a 250 mg tablet of
vitamin C, C6H8O6. Express your answer in mol. What is the mass of all the oxygen atoms in
the tablet? Express your answer in mg.
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mols of vitamin C
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mass of oxygen atoms in mg
Question 13. Sketch a 2D structure for pentadiene, and try to draw this molecule indicating its
true geometry in 3D also. The “text” formula for it is: CH2(CH)3CH3. For extra credit, draw a
“barebones” stick structure (i.e., without labeling the H and C atoms--this is how the real
organic chemists do it).
Chem 1201 Sec. 4
Exam #7
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