Name______________________________________________
Student ID Number___________________________________
LAB Sec. # ___; TA: __________; Lab day/time: __________
Fall 2016
Dr. Bryan Enderle
CHEMISTRY 2C (Section B)
Exam I
Instructions:
CLOSED BOOK EXAM! No books, notes, or additional scrap paper
are permitted. All information required is contained on the exam. Place
all work in the space provided. If you require additional space, use the
back of the exam. A scientific calculator may be used (if it is a
programmable calculator, its memory must be cleared before the exam).
Read each question carefully.
(1) For Parts I and II, there is no partial credit given (unless marked).
For Part I, only answers marked on this cover page will be graded.
You must also fill in your TA’s name at the top of the page. Failure
to do either of these will result in a 10 point deduction.
(2) The last two pages contain a periodic table and some useful
information. You may remove it for easy access.
(3) If you finish early, RECHECK YOUR ANSWERS!
U.C. Davis is an Honor Institution
Possible Points
Points
Multiple Choice
(circle one)
1.
a
b
c
d
e
2.
a
b
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d
e
3.
a
b
c
d
e
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a
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a
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8.
a
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9.
a
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10. a
b
c
d
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11. a
b
c
d
e
b
c
d
e
#1–12. (3 pts each)
/ 36
12. a
#13-14. (6 pts each)
/ 12
1-12 total pts:
#15-17. (24 pts)
/ 24
#18-19. (18 pts)
/ 18
#20. (17 pts)
/ 17
Total Score (107)
/ 107
13. a
b
c
d
e
14. a
b
c
d
e
13-14 total pts:
Name: ____________________________________
Exam I (Page 2 of 8)
Part I: Multiple Choice, Concepts (3 points each)
Select the best answer and enter your choice on the cover sheet – No partial credit
1. Which of the following metals would “plate-out” first?
(a) Li (b) Mg (c) Al (d) Cu (e) Pb
2. Which of the following metals will oxidize first?
(a) Li (b) Mg (c) Al (d) Cu (e) Pb
3. Which statement about batteries is not true?
(a) ξ° is not zero at equilibrium.
(b) ξ < 0 indicates spontaneity.
(c) Spontaneity for various T and P is determined by ξ not ξ°.
(d) ξ° does not change as solution concentration values change.
4. Which of the following complex ions do not have a coordination number of 6?
(a) [Fe(en)3]3+ (b) [Fe(EDTA)]- (c) [Fe(CO)6]3+ (d) [Fe(ox)2]5. Select the correct name for [Sc(CN)2(CO)4]3[Fe(NCS)3(SCN)3]
(a) tetracarbonylbicyanoscandium(III) trithiocyanato-N-trithiocyanato-S-ferrate(III)
(b) dicyanotetracarbonylscandate(III) trithiocyanato-N-trithiocyanato-S-iron(III)
(c) tetracarbonyldicyanoscandium(II) trithiocyanato-N-trithiocyanato-S-ferrate(IV)
(d) tetracarbonyldicyanoscandium(III) trithiocyanato-N-trithiocyanato-S-ferrate(III)
(e) Nothing can be done. It is impossible.
6. In a galvanic cell, oxidation occurs at the:
(a) anode (b) cathode (c) salt bridge (d) electrolyte
7. Determine ξ°cell for the reaction: 2 Al(s) + 3 Zn2+(aq) → 2 Al3+(aq) + 3 Zn(s).
(a) 0.913 V (b) -2.439 V (c) 2.439 V (d) -1.063 V (e) -0.913 V
8. For the reaction: Mg(s) + AgNO3(aq) → Ag(s) + Mg(NO3)2(aq)
Is the reaction spontaneous and why?
(a) No, Mg(s) does not react with Ag+.
(b) No, ξ° is a positive value.
(c) No, ξ° is a negative value.
(d) Yes, ξ° is a positive value.
(e) Yes, ξ° is a negative value.
9. In the cell Fe2+(aq) Fe3+(aq) || Cu2+(aq) Cu(s) which will increase the cell voltage the
most?
(a) Halve [Cu2+] (b) Halve [Fe2+] (c) Double [Cu2+] (d) Double [Fe2+]
10. Which of the following transition elements would have the smallest atomic radius?
(a) Fe (b) Zn (c) Ti (d) Ru (e) Os
11. Which of the following is not a common characteristic of the alkali metals?
(a) easily reduced (b) visible flame colors (c) oxide formation (d) weak metal bonding
Name: ____________________________________
Exam I (Page 3 of 8)
12. As ethylenediamine is added to a green solution of [Ni(H2O)6]2+, the water molecules are
replaced two at a time by ethylenediamine to produce the sequence of ions: [Ni(H2O)6]2+,
[Ni(en)(H2O)4]2+, [Ni(en)2(H2O)2]2+, and [Ni(en)3]2+. How does the color change through the
sequence?
(a) The color changes toward red with the addition of ethylenediamine.
(b) The color changes toward violet with the addition of ethylenediamine.
(c) The color changes are green, red, violet, and then blue with the addition of
ethylenediamine.
(d) Adding ethylenediamine will have no effect on field strength or wavelength of light.
Part II: Multiple Choice, Short Calculations, Fill in the Blank
Select the best answer and enter your choice on the cover sheet. If you do not select the
correct answer, you may show work for up to half credit per question.
13. How many coulombs would be needed to deposit all of the Ag+ ion from 600 mL of a
solution 0.250 M in Ag+?
(a) 1.45 × 107 C (b) 1.56 × 106 C (c) 1.45 × 104 C (d) 2.41 × 104 C (e) 1.56 × 104 C
14. For the reaction: Mg(s) + AgNO3(aq) → Ag(s) + Mg(NO3)2(aq)
Estimate Keq at 25°C.
(a) 5 × 10106 (b) 2 × 1053 (c) 4 × 1052 (d) 1 × 1027 (e) 10-107
Name: ____________________________________
Exam I (Page 4 of 8)
15. (12 total points) Fill in the blanks in the table below for the given molecules. When asked about the
metal, answer the questions for the underlined metal.
Molecule
Coordination
Number of
Metal
Electronic
Config. of
Metal (i.e., d8)
Could the
molecule be
chiral?
VSEPR shape (if
more than one
possible, list all)
[Fe(en)3]PO4
6
d5
yes
Octahedral
Name [Fe(en)3]PO4 = tris(ethylenediamine)iron(III) phosphate
Mg[CoBr3(H2O)]2
4
d7
No
Tetrahedral,
Square Planar
Name Mg[CoBr3(H2O)]2 = magnesium aquatribromocobaltate(II)
16. (4 total points) Reactions: fill in the blank with the appropriate compounds and balance the
reactions using whole numbers.
(a)
→ CrCl2 (aq) + H2 (g)
(b) AgNO3 (aq) + NaI (aq) →
Answer: Cr (s) + 2 HCl (aq)
Answer: AgI (s) + NaNO3 (aq)
17. (8 points) Fill in the blank: in the column marked “Answer” to the left of each statement, fill in the
statement number that best describes the element.
Answer
Sc
Mn
Ag
Pt
Statement – Which element is it?
1. This element is found in uranium ores. +3 is its most common oxidation
state. It has similar chemistry to Mg, Al, Y, and the lanthanides.
2. This metal can vary in oxidation state from +2 to +7. Some of its
applications include batteries (dry cells) and catalysts. It is also a
biologically relevant element.
3. The name of this coinage metal means “grey” or “shining.” It tarnishes
black when it reacts with sulfur. An application is the button battery.
4. This powerful catalyst is not very reactive. Its name means “little silver”
and is also commonly used in jewelry. Common oxidations states are +2
and +4.
Name: ____________________________________
Exam I (Page 5 of 8)
18. (6 points) Draw all stereoisomers for [CuI(CO)2(NH3)3]+.
Fac with cis, mer with cis, and mer with trans.
Part III: Long Answer
Please show all work for calculations – Partial credit may be given
19. (12 total points) Solve the following for [Fe(H2O)6]3+ and [Cu(CN)2]–.
(a) (11 points) Draw the CFT diagram for each in the space provided. (Include an energy
axis, appropriately filled electrons, labeled orbital levels, Δ, etc). Circle the coordination
compound with the largest number of unpaired electrons.
[Fe(H2O)6]3+
[Cu(CN)2]–
Fe: Octahedral CFT, weak field, 5 upe  Correct Answer
Cu: Linear, strong field, all electrons paired
(b) (1 point) Which of the compounds, [Fe(H2O)6]3+ or [Cu(CN)2], are paramagnetic, if any?
Fe compound
Name: ____________________________________
Exam I (Page 6 of 8)
20. (17 total points) The concentration cell described below has a measured cell potential of
0.180 V. (Assume 25ºC)
Ag(s) | Ag+(aq) (satd Ag3PO4) || Ag+(aq) (0.140 M) | Ag(s)
(a) (4 points) Write the overall cell reaction in the box provided. Include state symbols.
Ag(s) + Ag+(aq) → Ag+(aq) + Ag(s)
Or Ag+(aq) → Ag+(aq)
(b) (2 points) Determine ξ° and n for this cell. Include units in your answer.
ξ° = 0 V
n=1
(c) (5 points) Determine the concentration of aqueous silver at the anode [Ag+].
ξ = ξ° - (0.025693/n) ln Q, Q = [Ag+]/[Ag+]
0.180 V = 0 V - (0.025693/1) ln x/0.140 M
x = 1.3e-4 M
[Ag+] = (d) (6 points) Draw out the galvanic cell using the template below. Fill in electron flow, electrodes,
cathode, anode, salt bridge (include a salt), and reactions (including arrows to indicate flow).
V
Must draw: electron
flow, electrodes,
cathode, anode, salt
bridge (include a salt),
and reactions
(including arrows to
indicate flow
Name: ____________________________________
Exam I (Page 7 of 8)
Constants:
R = 8.3145 J / mol K
F = 96,485 C/ mol e-
R = 0.08206 L atm / mol K
c = 2.9979 x 108 m / s
h = 6.626 x 10-34 J s
Spectrochemical Series: CN->CO>NO2->en>NH3>H2O>ox2->OH->F->SCN->Cl->Br->IEquations:
o
G    nFE cell
G   nFE cell
o
E cell

G  H   TS  G  G   RT ln Q
800
620
r
400
430
v
o
b
y
g
580
560
490
0.025693
ln K eq
n
0.0592
log Q
n
RT
o
 E cell

ln Q
nF
o
E cell  E cell

G    RT ln K eq
E cell
Name: ____________________________________
Exam I (Page 8 of 8)