KING FAHD UNIVERSITY OF PETROLEUM AND MINERALS
CHEMISTRY DEPARTMENT
CHEM 102-091
MAJOR II-EXAM
TEST CODE NUMBER 001

STUDENT NUMBER:    _____________________________
NAME :                          _____________________________
SECTION NUMBER:    _____________________________
INSTRUCTIONS
1.
Write your student number, name, and section number on the EXAM COVER page.
2.
Write your student number, section number, and your name on your EXAM ANSWER FORM.
3.
Bubble in pencil your student number and your section number on the EXAM ANSWER FORM.
4.
Bubble in pencil on your EXAM ANSWER FORM the correct answer to each of the questions. .
You must not give more than ONE answer per question.
5.
At the end of the exam return the EXAM ANSWER FORM to the proctor.
6.
The exam contains 20 multiple choice questions and the time allowed is 80 min (1 hrs and 20 min). Time will be announced after 40 minutes and again 10 minutes before the end of the exam.

Important constants
Gas Constant (R)
= 0.0821
= 8.31
= 8.31 x 107
L.atm/(mol.K)
J/(mol.K)
g.cm2/(sec2.mol.K)
Planck’s Constant (h)
= 6.626 x 10-34
= 6.626 x 10-34
J.sec/particle kg.m2/(sec.particle)
Velocity of light (c)
= 2.998 x 108
m/sec
Avogadro’s number (N)
= 6.022 x 1023
particles/mole
Bohr’s Constant (RH)
= 2.179 x 10-18
J/particle
Faraday (F)
= 96485
Coulombs
Specific heat of H2O
= 4.18
J/(g.oC)
















1.
The Ksp for Mn(OH)2 is 2.0 × 10–13. At what pH will Mn(OH)2 begin to precipitate from a solution in which the initial concentration of Mn2+ is 0.10 M?
A.
6.47
B.
13.3
C.
5.85
D.
7.03
E.
8.15


2.
It is observed that 7.45 mmol of BaF2 will dissolve in 1.0 L of water. Use these data to calculate the value of Ksp for barium fluoride.
A.
1.1e–4
B.
4.1e–7
C.
1.7e–6
D.
2.2e–4
E.
5.6e–5


3.
Consider the reaction 2NO2(g) N2O4(g); ΔH° = –56.8 kJ     ΔS° = –175 J/K In a container (at 298 K) N2O4(g) and NO2(g) are mixed with initial partial pressures of 2.4 atm and 0.42 atm, respectively. Which of the following statements is correct?
A.
Some N2O4(g) will decompose into NO2(g).
B.
Some NO2(g) will dimerize to form N2O4(g).
C.
The system is at equilibrium at these initial pressures.
D.
The final total pressure must be known to answer this question.
E.
The final volume must be known to answer this question.


4.
Consider the following hypothetical reaction (at 310.6 K). Standard free energies in kJ/mol are given in parentheses.

   A      B   +   C      = ?
      (-32.2)          (207.8)            (-237.0)

What is the value of the equilibrium constant for the reaction at 310.6 K?
A.
0.31
B.
1.0
C.
8.1e4
D.
273
E.
0.42


5.
For which of the following processes would ΔS° be expected to be most positive?
A.
O2(g) + 2H2(g) → 2H2O(g)
B.
H2O(l) → H2O(s)
C.
NH3(g) + HCl(g) → NH4Cl(g)
D.
2NH4NO3(s) → 2N2(g) + O2(g) + 4H2O(g)
E.
N2O4(g) → 2NO2(g)


6.
For a certain process at 355 K, ΔG = -12.4 kJ and ΔH = -9.2 kJ. Therefore, ΔS for the process is
A.
0
B.
9.0 J/K mol
C.
–9.0 J/K mol
D.
–25.9 J/K mol
E.
25.9 J/K mol


7.
Substance X has a heat of vaporization of 41.8 kJ/mol at its normal boiling point (423oC). For the process X (l) X (g) at 1 atm and 423oC calculate the value of ΔSSURR.
A.
0
B.
60.1 J/K mol
C.
99 J/K mol
D.
–60.1 J/K mol
E.
–99 J/K mol


8.
Gold is produced electrochemically from an aqueous solution of Au(CN)2– containing an excess of CN–. Gold metal and oxygen gas are produced at the electrodes. How many moles of O2 will be produced during the production of 1.00 mole of gold?
A.
0.25
B.
0.50
C.
1.00
D.
3.56
E.
4.00


9.
A common car battery consists of six identical cells each of which carries out the reaction

   

The value of for such a cell is 2.041 V. Calculate at 25oC for the reaction.
A.
–196.9 kJ
B.
–98.5 kJ
C.
–393.9 kJ
D.
–787.7 kJ
E.
–590.8 kJ


10.
Consider the following reduction potentials:

         = +0.343 V
         = -0.130 V

For a galvanic cell employing the Cu, Cu2+ and Pb, Pb2+ couples, calculate the maximum amount of work that would accompany the reaction of one mole of lead under standard conditions.
A.
–41.1 kJ
B.
–45.6 kJ
C.
–91.3 kJ
D.
No work can be done. The system is at equilibrium.
E.
More information are required to answer this problem.


11.
The galvanic cell described by has a standard cell potential of 1.101 volts. Given that has an oxidation potential of 0.762 volts, determine the reduction potential for .
A.
1.863 V
B.
–1.863 V
C.
–0.339 V
D.
0.339 V
E.
none of these


12.
How many electrons are transferred in the following reaction? SO32–(aq) + MnO4–(aq) → SO42–(aq) + Mn2+(aq)
A.
6
B.
2
C.
10
D.
4
E.
3


13.
Calculate the change in energy in kJ/mol for the transmutation of radium from the given molar masses:
 
 
 
Ra
→
 
He
+
 
 
 
 
 
g/mol 226.0254
 
4.0026
 
222.0176
 
A.
–5.2 kJ/mol
B.
–1.6 kJ/mol
C.
–4.7 × 1014 kJ/mol
D.
–4.7 × 108 kJ/mol
E.
+1.6 × 108 kJ/mol


14.
Which of the following result(s) in an increase in the entropy of the system?
I.
 
(See diagram above.)
II.
 
Br2(g) → Br2(l)
III
 
.NaBr(s) → Na+(aq) + Br–(aq)
IV.
 
O2(298 K) → O2(373 K)
V.
 
NH3(1 atm, 298 K) → NH3(3 atm, 298 K)
 
A.
I
B.
II, V
C.
I, III, IV
D.
I, II, III, IV
E.
I, II, III, V


15.
Which of the following is true for the cell shown here? Zn(s)  Zn2+(aq)  Cr3+(aq)  Cr(s)
A.
The electrons flow from the cathode to the anode.
B.
The electrons flow from the zinc to the chromium.
C.
The electrons flow from the chromium to the zinc.
D.
The chromium is oxidized.
E.
The zinc is reduced.


16.
A radioactive sample has an initial activity of 2.00 106 cpm (counts per minute), and after 4.0 days, its activity is 9.0 105 cpm. What is its activity after 39 days?
A.
6.7 cpm
B.
8.3e2 cpm
C.
2.4e3 cpm
D.
2.1e–10 cpm
E.
1.3 cpm


17.
A sample of wood from an Egyptian mummy case gives a count of 9.0 cpm/gC (counts per minute per gram of carbon). How old is the wood? (The initial decay rate of is 15.3 cpm/gC, and its half-life is 5730 years.) Ignore significant figures for this problem.
A.
2194 yr
B.
6887 yr
C.
4387 yr
D.
5437 yr
E.
7520 yr


18.
When the U-235 nucleus is struck with a neutron, the Zn-72 and Sm-160 nuclei are produced along with some neutrons. How many neutrons are emitted?
A.
2
B.
3
C.
4
D.
5
E.
6


19.
The nuclide Tl is the daughter nuclide resulting from the α decay of what parent nuclide?
A.
Pb
B.
Au
C.
Hg
D.
Bi
E.
He


20.
Which of the following balanced equations is labeled incorrectly?
A.
fission: Bi + He → At + 2n
B.
fusion: H + H → H + H
C.
bombardment: Pu + n → Am + e
D.
beta production: U → Np + e
E.
positron decay:


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