Chemistry 110
Final Exam, 8:00 Section
G. E. Rodgers
(There are 200 points on this exam.)
GOOD LUCK!
HAPPY HOLIDAYS!
December 15, 2003
Name _________________________________
Honor code: ____________________________
(20 pts) I. Multiple Choice: Circle the letter corresponding to the best answer. Choice: Answer 10 of
the following 11 items. That is, you can omit answering one of these without penalty. Put an
asterisk next to the item you wish not to be graded.
1. Which of the following is true about Dr. Rodgers?
(a) He strips off his shirt in class under a black light.
(b) He is a Boston Red Sox fan.
(c) He thinks that Jean-Luc Picard is the best captain of a Star Fleet vessel.
(d) He thinks lone pairs of electrons are “scarier” than bonding pairs.
(e) His theories tend to be “quick and dirty”.
(f) His wife is a great cook and hostess.
(g) His Basset hound Dewey is a guest greeter extraordinaire.
(h) All of these are true.
2. In our green KaFeb(C2O4)c  dH2O compound, the oxalate anion is the
(a) loose base
(e) Erroneous base
(b) loose cannon
(f) Bronchial base
(c) Lewis base
(g) Lewis acid
(d) Clark base
(h) none of these
Given the following skeletal equation: Ce4+ + SO32- + H2O  Ce3+ + SO42- + H+, answer
the next two questions:
3. Which reactant or product is the oxidizing agent?
(a) Ce4+
(b) SO32-
(c) H2O
(d) Ce3+
(e) SO42-
(f) H+
4. Once the above skeletal equation is balanced the Ce4+: SO32- mole ratio would be
(a) 1:1
(b) 2:1
(c) 1:2
(d) 3:1
(f) 1:3
(f) none of these
5. Using Lewis structures with the most favorable formal charges, the average bond order of
the P-O bonds in the phosphate ion is
(a) 0.25
(b) 1.00
(c) 1.25
(d) 1.33
(e) 1.50
(f) 1.75
(g) 2.00
6. Of NaCl, KCl, RbCl, and CsCl, the salt with the greatest magnitude of lattice energy is
(a) NaCl
(b) KCl
(c) RbCl
(d) CsCl
(e) not enough information to tell
Final Exam, Chemistry 110, Fall 2003
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7. The proper name of CrTeO4 is
(a) chromium(II) thallate
(b) chromium tellurium(VI)oxide
(c) chromium(III) tetraoxotellenate (d) chromium(I) tellurate
(e) chromium(II) tellurite
(f) chromium(II) tellurate
8. The best name for HBr(aq) is
(a) hydrogen bromide
(d) hydrobromous acid
(b) hydrogen bromate
(c) hydrobromic acid
(e) hydrohypobromous acid (f) none of these
9. Which of the following polyatomic ions contains the shortest Br-O bonds?
(a) hypobromite
(b) bromite
(c) bromate
(d) perbromate
10. Which of the following molecules are non-polar?
(a) CH2Cl2
(b) CHCl3
(e) none are polar
(c) CH3Cl
(d) CH3OCH3
(f) all are polar
11. The hybridization of the underlined atom in bold type in H2N-CH2-CHO is
(a) sp
(b) sp2
(c) sp3
(d) sp3d
(e) sp3d2
II. Properties of Nickel
(6 pts)
1. Density. When a piece of nickel of mass 88.78 grams is dropped into a graduated cylinder
containing 25.6 mL of water, the water level rises to 35.6 mL. What is the density of the nickel
(in grams per mL)?
(10 pts) 2. Specific Heat. When this same piece (see above) of nickel is heated to 152.6C and placed
in 209 g of water at a temperature of 25.0C, the water is heated to 30.5C. Determine the
specific heat of the nickel. Assume that no heat is lost to the container. (The specific heat of
water is 4.184 J/g-deg.)
Final Exam, Chemistry 110, Fall 2003
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II. Properties of Nickel (continued)
(10 pts) 3. Work Function. When light with a wavelength of 218 nm falls on a nickel metal surface,
an electron is ejected at a speed of 4.88 x 105 m/s. Calculate the work function of nickel?
(mass of electron = 9.109 x 10-31 kg)
(10 pts) 4. Atomic Weight. Briefly but carefully explain how the atomic weight of nickel could be
determined using a mass spectrometer? Use a detailed diagram to aid your explanation.
(15 pts) 5. Electronic Configurations (in this and other universes).
(a) Write the full electronic configuration of nickel.
(b) Write the abbreviated orbital or box-like diagram for nickel.
(c) Write the set of quantum numbers for the first electron to removed from a nickel atom on
the way to producing the Ni2+ cation.
(d) Suppose you are in a “Spock Universe” in which there are three allowed values of the spin
quantum number, ms. Write the electron configuration for nickel under those circumstances.
What type of element (name a section of the periodic table) would nickel be under these
circumstances? Briefly justify your answer.
Final Exam, Chemistry 110, Fall 2003
(6 pts)
Page 4 of 7
III. Nomenclature of Nickel Compounds. Fill in the appropriate formula or name for the
following nickel compounds
(a)
NiC2O4 · 3H2O
____________________
(b)
____________
nickel(II) chlorite
IV. Nickel Oxalate Salts in Aqueous Solution.
(12 pts) 1. To represent the dissolving of NiC2O4 · 3H2O(s) in water we write the following equation:
H2O
NiC2O4 · 3H2O(s)
 Ni2+(aq) + C2O42-(aq) + 3H2O
Draw diagrams showing exactly what is meant by the symbols for the two aqueous (aq)
products. Be sure that your diagrams are as geometrically accurate as possible.
Ni2+(aq):
C2O42-(aq):
(10 pts) 2. Suppose you have prepared a solution that is 0.0638 M in (NH4)2Ce(NO3)6. You weigh about
0.280 g of NiC2O4 · 3H2O into a 250 mL Erlenmeyer flask and prepare to titrate the oxalate in
the above compound in aqueous solution using ferroin as an indicator. About how many mL of
the (NH4)2Ce(NO3)6(aq) solution do you expect to use in the titration? The skeletal equation for
the reaction of Ce4+(aq) and C2O42- is given below. Show your calculations as clearly as
possible.
Ce4+(aq) + C2O42-(aq)  Ce3+(aq) + CO2(aq)
Final Exam, Chemistry 110, Fall 2003
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(15 pts) V. The Nature of Atomic Orbitals. Using the concept of the wave-particle duality of matter,
describe as clearly as possible what 2s and 2p atomic orbitals are. In as much detail as time
allows, explain why the 2s orbital is of lower energy than the 2p orbital in a many-electron atom
(MEA) but these two orbitals are degenerate in a hydrogen-like species. Draw and refer to
radial distribution functions (and/or dot density diagrams ), effective nuclear charge, and
Coulomb potential energy as part of your answer. Label your radial distribution functions
clearly.
(13 pts) VI. Lewis Structures Revisited: Provide Lewis structures for the following molecules, salts,
or ions.
1. SnCl2
2. K2C2O4
3. H2SO3
(13 pts) VII. Mass Percentages and Formulas: A compound is 29.7% by mass sulfur and 70.3%
fluorine. Determine its empirical formula, name the compound, and determine its molecular
geometry by drawing a diagram and giving it a descriptive name such as “linear”, “trigonal
planar”, etc. Show all of your work as clearly as possible.
Final Exam, Chemistry 110, Fall 2003
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(16 pts) VIII. Another Representative –ic Acid in All Its Glory! Draw Lewis, VSEPR, and VBT
diagrams of boric acid. Assign formal charges in the Lewis structure, estimate the value of
bond angles in the VSEPR diagram, and label all orbitals and bonds in the VBT diagram. If
there are resonance structures, use one of these in the VBT section of your answer.
Lewis
VSEPR
VBT
IX. Ammonia and the Return of the Natives!
(12 pts) 1. Draw the abbreviated box-like or orbital diagrams for nitrogen and hydrogen. What native
atomic orbitals would these atoms use to form ammonia, NH3? Under these circumstances,
what would be the value of the H-N-H bond angle in this molecule? Explain your answer.
Would the bonds be equivalent? Why or why not?
(7 pts)
2. Draw a diagram showing the best valence bond
picture of NH3. Carefully label all orbitals and
types of bonds in your diagram.
Final Exam, Chemistry 110, Fall 2003
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(10 pts) 3. Using ammonia as your starting point, how would you determine the N-H bond energy?
Carefully show a chemical equation that will allow you to determine this bond energy. Besides
the Hf of NH3(g), what other standard heats of formation would you need to carry out the
calculation? Carefully describe how you would determine a value for the DN-H?
(10 pts) X. Ammonia Production. (a) How much ammonia can be produced by the Haber-Bosch
Process (the skeletal equation for which is shown below) if we start with 12.0g N2 and 2.00g
H2? Assuming 100% yield, how many grams of which reactant will be left over after the
reaction?
High T and P
N2(g) + H2(g)  NH3(g)
Fe
(5 pts)
(b) If 10.0 grams of ammonia are actually produced in the above reaction, calculate the percent
yield of the Haber-Bosch reaction.