CHEM 1412 SAMPLE FINAL EXAM
PART I - Multiple Choice (2 points each)
_____ 1.
In which colligative property(ies) does the value decrease as more solute is added?
A. boiling point
C. vapor pressure
_____ 2.
What is the molarity of a solution prepared by dissolving 25.2 g of CaCO3 in 600 mL of solution?
A. 0.420 M
_____ 3.
C. 2.58 °C
D. -2.58 °C
B. 4.89 atm
C. 25.1 atm
D. 36.0 atm
B. 314 mm Hg
C. 34.9 mm Hg
D. 69.8 mm Hg
B. M-1 s-1
C. M-2 s-1
D. s-1
For second-order reactions the slope of a plot of 1/[A] versus time is
A. k
_____ 8.
B. -0.258 °C
For first-order reactions, the rate constant, k, has the units
A. M s-1
_____ 7.
D. 0.325 M
The vapor pressure of pure ethanol at 60 °C is 349 mm Hg. Calculate the vapor pressure at
60 °C of a solution prepared by dissolving 10.0 mol of naphthalene (nonvolatile) in 90.0 mol of
ethanol.
A. 600 mm Hg
_____ 6.
C. 0.042 M
What is the osmotic pressure produced by a 1.20 M glucose (C6H12O6) solution at 25 °C ?
A. 29.4 atm
_____ 5.
B. 0.567 M
What is the freezing point of an aqueous glucose solution that has 25.0 g of glucose, C6H12O6,
per 100.0 g of H2O ? (Kf for water = 1.86 °C /m)
A. 0.258 °C
_____ 4.
B. freezing point and osmotic pressure
D. freezing point and vapor pressure
B. k/[A]0
C. kt
D. -k
If the reaction 2A + 3D  Products is first-order in A and second- order in D, then the rate law
will have the form Rate =
A. k[A]2[D]3
B. k[A][D]
C. k[A]2[D]2
D. k[A][D]2
_____ 9. In the first-order reaction A  Products, the initial concentration of A is 1.56 M and the
concentration is 0.869 M after 48.0 min. What is the value of the rate constant, k ?
A. 3.84 X 10-2 min-1
B. 2.92 X 10-2 min-1 C. 5.68 X 10-2 min-1 D. 1.22 X 10-2 min-1
_____ 10. Consider the reaction
2 HI (g)
H2 (g) + I2 (g) .
What is the value of the equilibrium constant, Kc, if at equilibrium, [H2] = 6.50 X 10-7 M,
[I2] = 1.06 X 10-5 M, and [HI] = 1.87 X 10-5 M?
A. 3.68 X 10-7
B. 1.97 X 10-2
C. 1.29 X 10-16
D. 50.8
_____ 11. In the mechanism below, which substance is the catalyst in the reaction?
Step 1:
Step 2:
Step 3:
Step 4:
C + ClO2  ClO + CO
CO + ClO2  CO2 + ClO
ClO + O2  ClO2 + O
ClO + O  ClO2
A. ClO2
B. CO2
C. O
D. CO
_____ 12. For the reaction
CaO (s) + CO2 (g)
CaCO3 (s)
the equilibrium constant expression for Keq is
A [CO2]
C. [CaO][CO2] / [CaCO3]
_____ 13. The value of Kp for the reaction 2 NO2 (g)
at this temperature for the reaction N2O4 (g)
A. -1.52
B. 1.23
B. 1 / [CO2]
D. [CaCO3] / [CaO][CO2]
N2O4 (g) is 1.52 at 319 K. What is the value of Kp
2 NO2 (g) ?
C. 5.74 X 10-4
D. 0.658
_____ 14. Which of the following is true for the following voltaic cell?
Zn (s)  Zn2+(aq)  Cr3+ (aq)  Cr (s)
A.
B.
C.
D.
The electrons flow from cathode to the anode.
The electrons flow from the zinc electrode to the chromium electrode.
The electrons flow from the chromium electrode to the zinc electrode.
Zinc is reduced in the reaction.
_____ 15. How many electrons are transferred in the following reaction?
2 ClO3- + 12 H+ + 10 I -  5 I2 + Cl2 + 6 H2O
A. 10
B. 12
C. 5
D. 30
_____ 16. A voltaic cell has E0cell = +1.00 V. The cell reaction
A. is not spontaneous
B. has K = 1
C. has G0 = 0
D. has a negative G0
_____ 17. Which energy conversion takes place in a galvanic cell?
A. electrical to chemical
C. mechanical to chemical
B. chemical to electrical
D. electrical to mechanical
_____ 18. The value of Kc for the reaction C(s) + CO2(g)
2CO(g) is 1.6. What is the equilibrium
concentration of CO if the equilibrium concentration of CO2 is 0.50 M ?
A. 0.31
B. 0.80
C. 0.89
D. 0.75
_____ 19. Consider the following reaction:
2 SO3 (g)
2 SO2 (g) + O2 (g)
H° = +198 kJ
All of the following changes will shift the equilibrium to the left () except one. Which one will
not cause the equilibrium to shift to the left?
A. removing some SO3
C. increasing the container volume
B. decreasing the temperature
D. adding some SO2
_____ 20. Calculate the pH of a solution which has [OH ] = 0.000700 M.
A. 3.15
B. 17.2
C. 10.8
D. 11
_____ 21. Which conjugate base of the following Brønsted-Lowry acids is incorrect?
(compound, conjugate base)
A. HClO, ClO-
B. H2S, HS-
C. H2SO4, HSO4-
D. NH3, NH4+
_____ 22. Predict whether aqueous solutions of the following compounds are acidic, basic, or neutral.
Which answer is incorrect?
A. KNO3 (neutral)
C. KClO (acidic)
B. NaC2H3O2 (basic)
D. NaCN (basic)
_____ 23. Calculate the pH of a buffer solution which is 0.20 M in formic acid and 0.15 M in sodium formate.
(Ka for formic acid = 1.8 X 10-4)
A. 2.4 X 10-4
B. 3.62
C. 0.82
D. 8.33
_____ 24. If X is the molar solubility of a slightly soluble ionic compound, which one of the following Ksp
expressions is incorrect?
A. Ag2S, Ksp = X2
C. BaSO4, Ksp = X2
B. AgCl , Ksp = X2
D. Cu(OH)2, Ksp = 4X3
_____ 25. For each of the following reactions, predict whether the entropy change, S, is positive or negative:
(I) 2 K (s) + Br2 (l)  2 KBr (s)
(II) 2 MnO2 (s)  2 MnO (s) + O2 (g)
A. (I) positive, (II) positive
C. (I) positive, (II) negative
B. (I) negative, (II) positive
D. (I) negative, (II) negative
_____ 26. Using the given values of S°, calculate the value of S° for the reaction
0
S (J/mole K):
C2H4 (g)
219.5
A. -120.6 J/K
H2 (g) 
130.59
+
B. 120.6 J/K
C2H6 (g)
229.5
C. 10.0 J/K
D. 140.0 J/ K
_____ 27. Given the following unbalanced redox reaction:
Fe2+ + Cr2O7 2-  Fe3+ + Cr 3+
What is the coefficient of Fe3+ in the balanced equation in acidic solution?
A. 1
B. 2
C. 3
D. none of these
_____ 28. Given the standard reduction potentials for the following half reactions:
Cr3+ + 3e-  Cr(s)
E0 = -0.73 V
Br2 + 2e-  2 Br-
E0 = +1.09 V
What is the cell voltage, E0cell, for a voltaic cell using these reactions?
A. 1.82 V
B. 0.36 V
C. 4.75 V
D. 1.79 V
_____ 29. Which of the following represents a positron?
1
A. 1H
B.
0
-1e
C.
0
+1e
4
D. 2He
_____ 30. Which of the following balanced equation is labeled incorrectly?
A. Beta decay,
239
92U

B. Alpha bombardment,
239
93Np
24
11Na
7
C. Electron capture, 4Be +
D. All are correctly labeled.
+
0
-1e
+
0
-1e
4
2He


7
3Li
27
13Al
+
1
0n
_____ 31. Which of the following pairs is incorrect?
A. ethane - C2H6
B. hexane - C6H14
C. decane - C10H22
D. heptane - C7H14
_____ 32. Which of the following is a general formula for a non-cyclic alkene which contains n carbon atoms and
one double bond?
A. CnHn
B. CnH2n+2
C. CnH2n
D. CnH2n-2
_____ 33. Classify the following molecule according to its functional group:
CH3CH2 - C= O

OCH3
A. ester
B. aldehyde
C. ketone
D. carboxylic acid
_____ 34. What is the correct IUPAC name of the following compound?
H3C
CH2CH3
C=C
H3C
Cl
A. 3-chloro-2-methyl-2-pentene
C. 1,1-dimethyl-1-butene
B. 3-chloro-4-methylpentene
D. 1-chloro-1-ethyl-2,2-dimethylpropene
_____ 35. Which of the following is the correct condensed molecular formula for isopropyl alcohol?
A. CH3CH2CH2OH
CH3

C. CH3- C -CH2OH

CH3
B. CH3CHCH3

OH
D. CH3CH2 = CH-OH
PART II - Show work (5 points each)
Please write your complete work in the space provided. Partial credit will be given.
1.
A solution is prepared by dissolving 6.00 g of an unknown nonelectrolyte in enough water to make
1.00 L of solution. The osmotic pressure of this solution is 0.750 atm at 25.0 °C. What is the molecular
weight of the unknown solute?
2.
Rate data were obtained for the following reaction:
A (g) + 2 B (g)  C (g) + D (g)
Experiment
1
2
3
What is
Initial [A], M
0.15
0.30
0.15
Initial [B], M
0.10
0.10
0.20
Initial Rate, M s-1
0.45
1.8
0.9
a) the rate law, and
b) the value of the rate constant k (with units) for the reaction?
3.
A rainwater sample is found to have a pH of 6.30. What are
a) the molar concentrations of H+(aq) and OH-(aq), and
b) the pOH of the sample?
4.
A 50.0 mL sample of 0.50 M acetic acid, HC2H3O2, is titrated with 0.150 M NaOH. Calculate the pH of
the solution after 25.0 mL of the base have been added. (Ka for acetic acid = 1.8 X 10-5)
5.
If a constant current of 5.00 amperes is passed through a solution containing Cr3+ for 1.50 hr, how many
grams of Cr metal will plate out on to the cathode?
6.
The half-life of strontium-90 is 28.1 years. How long will it take a 10.0 g sample of strontium-90 to
decay until only 0.10 g of strontium-90 remains in the sample?
Answers
Part I - Multiple-Choice
1. D
2. A
3. D
4. A
5. B
6. D
7. A
8. D
9. D
10. B
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
A
B
D
B
A
D
B
C
C
C
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
D
C
B
A
B
A
D (Ans. = 6)
A
C
D
31.
32.
33.
34.
35.
D
C
A
A
B
Part II - Show-Work
1. 1)  = MRT, M =
2) M = moles ,
L
=
0.750 atm
(0.08206 L atm / mol K)(298.15 K)
MW = grams
moles
-
=
6.00 g
0.03065455 mol
-
k = 200 M 2 s 1
3. a) [H+] = 10-pH = 10-6.30 = 5.01 X 10-7 M
[OH-] =
= 0.03065455 mol/L
moles = M X L = (0.03065455 mol/L)(1.00 L) = 0.03065455 mol
3) moles = grams ,
MW
2. Rate = k[A]2[B]

RT
1.0 X 10-14 = 2.00 X 10-8 M
5.01 X 10-7 M
b) pOH = -log[OH-] = -log(2.00 X 10-8 M) = 7.70
Or, pOH = 14 - pH = 14 - 6.30 = 7.70
= 196 g/mol (3 significant figures)
4.
HC2H3O2 (aq)
0.0250 mol
0.02125 mol
Initially:
After rxn:
+ NaOH (aq) 
0.00375 mol
0
NaC2H3O2 (aq) + H2O (l)
0
0.00375 mol
-
pH = -log(1.8 X 10-5) + log(0.00375 mol / 0.02125 mol) = 3.99
5. Coulombs
=
5.00 C
s
X
1.50 hr X
1
60 min
hr
X
60 s = 27000 C
min
Grams of Cr = 27000 C X 1 mol e- X 1 mol Cr X 51.996 g Cr = 4.85 g
1
96485 C
3 mol emol Cr
6. k = ln(2) = ln(2) = 0.024667 yr-1
t1/2
28.1 yr
ln(0.10 g) = -(0.024667 yr-1) t + ln(10.0 g) ,
t = 187 yr