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Name______________________________________________
Student ID Number___________________________________
LAB Sec. # ___; TA: __________; Lab day/time: __________
Fall 2006
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).
(1) Read each question carefully.
(2) For Parts I and II, there is no partial credit given and only answers
marked on this cover page will be graded.
(3) The last two pages contains a periodic table and some useful
information. You may remove it for easy access.
(4) If you finish early, RECHECK YOUR ANSWERS!
Multiple Choice
(circle one)
1.
a b
c d
e
2.
a b
c d
e
3.
a b
c d
e
4.
a b
c d
e
5.
a b
c d
e
6.
a b
c d
e
1-6 total pts:
7.
a b
c d
e
8.
a b
c d
e
7-8 total pts:
U.C. Davis is an Honor Institution
Possible Points
Points
#1–6. (3 pts each)
/ 18
#7-8. (5 pts each)
/ 10
#9. (6 pts)
/6
#10-11. (42 pts)
/ 42
#12. (27 pts)
/ 27
Total Score (103)
/ 103
Name: ____________________________________
Exam I (Page 2 of 9)
Part I: Multiple Choice, Concepts (3 points each)
Select the best answer and enter your choice on the cover sheet – No partial credit
1. (3 pts) Which of the following metals is most easily reduced?
(a) Li
(b) Ca
(c) Zn
(d) Ag
(e) Cu
2. (3 pts) Which of the following metals will oxidize first?
(a) Li
(b) Ca
(c) Zn
(d) Ag
(e) Cu
3. (3 pts) Which statement about batteries is not true?
(a) The reaction occurring in a primary cell battery is not reversible.
(b) A battery changes electrical energy to chemical energy for use in chemical
reactions.
(c) The hydrogen-oxygen fuel cell battery produces water as a product.
(d) The lead-acid battery in automobiles is rechargeable and has an approximate
potential of 12 volts.
(e) None of the above.
4. (3 pts) Choose the correct statement about atomic radii.
(a) Chromium is larger than cadmium.
(b) Yttrium is smaller than gold.
(c) Rhodium and platinum are the same size.
(d) Titanium is larger than zinc.
(e) Transition metals do not have atomic radii.
Name: ____________________________________
Exam I (Page 3 of 9)
5. (3 pts) Which of the following statements are true about applications of transition metals?
(a) Copper and silver are good conductors.
(b) Titanium is used as a pigment in paper.
(c) Iron is found in certain biomolecules.
(d) All of the above
(e) Metal coins consist of argon.
6. (3 pts) For the reactions below, what must be done to make the overall reaction
spontaneous? (See the table at the back of the exam for additional info.)
Mg2+ (aq) + 2 e- à Mg (s)
Al3+ (aq) + 3 e- à Al (s)
(a) Make the magnesium reaction an oxidation reaction.
(b) Make the aluminum reaction an oxidation reaction.
(c) Make the magnesium reaction a reduction reaction.
(d) Any combination of these reactions is spontaneous.
(e) Nothing can be done. It is impossible.
Name: ____________________________________
Exam I (Page 4 of 9)
Part II: Multiple Choice, Short Calculations, Fill in the Blank
Select the best answer and enter your choice on the cover sheet – No partial credit
7. (5 pts) What mass of aluminum can be deposited by the passage of a constant current of
5.00 A through an aluminum nitrate solution for 2.00 hours?
(a) 1.12
(b) 3.36 g
(c) 0.0559
(d) 0.672
(e) None of the above.
8. (5 pts) What is Keq of the spontaneous cell made from Zn/Zn2+ and Br2/Br- half cells?
(Use the table at the back to find useful information.)
(a) 5.75 x 10-6
(b) 3.03 x 1010
(c) 6.28 x 1061
(d) 3.30 x 10-11
(e) None of the above.
9. (6 pts) Write the correct name for the following transition metal compounds.
(a) [Cu(H2O)6]I2
Answer:
______________________________________________________________
(b) Ca[Fe(CN)5(CO)]
Answer:
______________________________________________________________
(c) [Mn(en)2(SO4)2]2SO4
Answer:
______________________________________________________________
Name: ____________________________________
Exam I (Page 5 of 9)
10. (30 pts) Fill in the blanks in the table below for the given molecules.
Molecule
Coordination
Number of
Metal
Electronic
Config. of
Metal (i.e., d8)
Oxidation
State
of Metal
Could the
molecule be
chiral?
VSEPR shape (if
more than one
possible, list all)
[CoCl2(H2O)2]Br
[MnIClBr(NH3)3]
K3[Fe(CN)6]
11. (12 pts) Draw the stereoisomers, if any, of [MnIClBr(NH3)3] below using the given template:
Mn
Mn
Mirror Plane
Name: ____________________________________
Exam I (Page 6 of 9)
Part III: Long Answer
Please show all work for calculations – Partial credit may be given
12. (27 pts) Answer the following questions given the galvanic cell written in shorthand below.
Write you answers in the marked boxes. Assume 25ºC.
Zn (s)
Zn2+ (aq)
VO2+ (aq), V3+ (aq)
Pt (s)
(a) (3 pts) Find the oxidation half reaction. Include state symbols.
Answer:
(b) (3 pts) Find the reduction half reaction. Include state symbols.
Answer:
(c) (3 pts) Find the overall reaction in acidic conditions. Include state symbols.
Answer:
Name: ____________________________________
Exam I (Page 7 of 9)
(d) (6 pts) 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
(e) (3 pts) The voltage for the reduction half reaction (part b) is +0.337 V. Using the table at the
back of the exam, find the standard potential (ξº) for the galvanic cell.
(f) (3 pts) Find the Gibbs free energy.
(h) (6 pts) If the galvanic cell is changed such that [Zn2+] = [H+] = [VO2+] = [V3+] = 0.50 M,
what is the potential (ξ) of the galvanic cell?
Name: ____________________________________
Exam I (Page 8 of 9)
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
Equations:
o
ΔG ° = − nFE cell
ΔG = − nFE cell
o
Ecell
=
ΔG° = ΔH ° − TΔS ° ΔG = ΔG° + RT ln Q
0.025693
ln K eq
n
h = 6.626 x 10-34 J s
o
Ecell = Ecell
−
ΔG ° = − RT ln K eq
0.0592
log Q
n
o
Ecell = Ecell
−
RT
ln Q
nF
Name: ____________________________________
Exam I (Page 9 of 9)