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CHEMISTRY 110 EXAM 4
DECEMBER 12, 2011
FORM A
3. For the following reaction, what is the reducing agent?
18 H+(aq) + 6 MnO4–(aq) + 5 I–(aq) " 6 Mn2+(aq) + 5 IO3–(aq) + 9 H2O (!)
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1. Mixing solutions of HCl (aq) and AgNO3 (aq) produces an
insoluble salt. Which of the following is the correct list of spectator
ions for this reaction?
A. MnO4–(aq)
B. I–(aq)
A. Ag+, NO3–
C. IO3–(aq)
B. H+, Cl–, Ag+, NO3–
D. H+(aq)
C. Ag+, Cl–
E. Mn2+(aq)
D. H+, Cl–
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E. H+, NO3–
4. Which of the following formula-name combinations is(are)
correct?
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2. Given the following:
2 NO (g) + 2 H2 (g)
N2 (g) + 2 H2O (g)
Kc = 6.5 ! 10
2
What is the Kc for the reaction below? Assume both reactions
occur at the same temperature.
2 N2 (g) + 4 H2O (g)
4 NO (g) + 4 H2 (g)
Kc = ???
A. 1.54 ! 10–3
B. 7.69 ! 10–4
C. 2.55 ! 101
i.
NH4Cl2
ammonium chloride
ii.
K2CO3
potassium carbonate
iii.
Ca3(PO4)2 calcium phosphate
A. i only
B. ii only
C. iii only
D. i and iii only
E. ii and iii only
D. 3.07 ! 10–3
E. 2.37 ! 10–6
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5. What is the maximum number of electrons with m! = –1 in the
ground state of Br?
7. If a selenium atom is in its ground state, which orbital has an
unpaired electron?
A. 1
B. 2
C. 4
D. 6
E. 8
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6. What is the solubility for helium in water at 30 °C, if its partial
pressure above the solution is 350 torr? The solubility constant for
helium in water at this temperature is 3.7 ! 10–4 M/atm
A. 1.7 ! 10–4 M
B. 3.4 ! 10–4 M
B.
A.
D.
C.
E. There are no unpaired electrons in Se.
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8. Which of the following molecules is polar?
H
H
C
A.
C
H
B. H
H
C
C
H
C. 5.6 ! 10–4 M
D. 6.0 ! 10–4 M
E. 9.0 ! 10–4 M
H
H
C
C.
E.
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C
Cl
C
Cl
C
Cl
Cl
H
C
D. Cl
C
H
Cl
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9. Which statement about this phase diagram for a pure substance is true?
11. Which of the following gives the correct relationships among the
first ionization energies of the elements?
A. At point a, the substance is entirely in the gaseous state.
B. At point b, solid and gaseous phases can co-exist at
equilibrium.
C. Point c is the triple point, where all three phases can coexist at equilibrium.
D. At point d, only the liquid phase exists.
E. None of the above statements is true.
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10. Consider the combination reaction between one mole of
hydrogen gas and one mole of sulfur (S(s)). What is the
molecular geometry of the product?
A.
B.
C.
D.
E.
tetrahedral
trigonal planar
bent
trigonal bipyramidal
trigonal pyramidal
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A.
B.
C.
D.
E.
i.
Rb > K > Li
ii.
Se > S > O
iii.
He > Ne > Ar
i only
ii only
iii only
both i and ii
both ii and iii
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12. The following electronic transitions occur in a H-atom. The
wavelengths of the emitted photons are 656 nm, 1875 nm, and
97.2 nm. Given that the energy levels shown are drawn to scale,
what are the wavelengths of each emitted photon?
Photon 1
!
*+!!
2+!!
3+!!
4+!!
5+!!
"#$%$&!'!
,-,!&.!
/0+(!&.!
'10-!&.!
'10-!&.!
/0+(!&.!
"#$%$&!(!
/0+(!&.!
'10-!&.!
/0+(!&.!
,-,!&.!
,-,!&.!
"#$%$&!)!
'10-!&.!
,-,!&.!
,-,!&.!
/0+(!&.!
'10-!&.!
Photon 2
Photon 3
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E
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13. Which orbital diagram corresponds to the ground state valence
shell electron configuration of Co2+?
15. Which of the following molecular geometries cannot be
observed in a molecule, for which the central atom is sp3d
hybridized?
A.
4s
3d
4s
3d
4s
3d
B.
C.
trigonal
planar
A
linear
T-shape
B
C
seesaw
D
trigonal
bipyramidal
E
D.
4s
3d
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4s
3d
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14. A mixture of 10 g each of O2, H2O, and N2 gases is contained in a
5.0 L flask at a temperature of 400 K. What is the total pressure of
the gases in the flask?
A. 5.0 atm
B. 6.0 atm
C. 7.0 atm
D. 8.0 atm
16. A compound made up of only iodine and chlorine contains
58.28% chlorine by mass. Assuming that the empirical formula
equals the molecular formula of this compound, what is the
hybridization of the central atom of this compound?
A. sp
B. sp2
C. sp3
D. sp3d
E. sp3d2
E. 9.0 atm
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17. Tetrahydrocannabinol (THC) is the main psychoactive
component of the cannabis plant. Its structure is shown below.
Which of the following statements is false.
19. Which one of these compounds has the highest boiling point?
A.
O
E
B.
D
OH
H
O
C.
C
O
O
B
A
D.
O
H
A. The angle labeled A is approximately 109.5°.
B. The angle labeled B is approximately 120°.
O
E.
C. The angle labeled C is larger than the angle labeled A.
D. The carbon atom labeled D is sp2 hybridized.
3
E. The carbon atom labeled E is sp hybridized.
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18. Which of the following ions will exhibit delocalized bonding?
NO2–
A.
B.
C.
D.
E.
NH4+
N 3–
NO2– only
N3– only
NO2– and N3–
NH4+ and N3–
NO2–, NH4+ and N3–
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20. Assume that an exhaled breath of air consists of 74.8% N2, 15.3% O2,
3.7% CO2, and 6.2% water vapor. (These are mole %.) If the total
pressure of the gases is 0.980 atm, the volume of the exhaled gas is
455 mL, and its temperature is 37°C, calculate the number of moles
of CO2 exhaled.
A. 6.5 ! 10–4 mol
B. 4.3 ! 10–3 mol
C. 1.3 ! 10–2 mol
D. 2.7 ! 10–3 mol
E. 1.1 ! 10–3 mol
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21. A balloon at 25oC and a total pressure of 1.2 atm contains a
mixture of gases according to the table below. Which of the gases
has the highest average molecular velocity?
Gas
CH4
CO2
SO2
N2
Mole Fraction (X)
0.210
0.003
0.052
0.735
A.
SO2
B.
CO2
C.
CH4
D.
N2
E.
They all have the same velocity.
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23. A typical car holds 60 L of octane (C8H18, a liquid with a density =
0.64 kg/L). If this entire amount of fuel is completely combusted in
air, what volume of CO2 is produced at 25°C and 1 atm?
A. 1.3 ! 104 L
B. 6.6 ! 104 L
C. 8.5 ! 103 L
D. 4.2 ! 104 L
E. 8.2 ! 102 L
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24. 31.5 mL of H2SO4 of unknown concentration was titrated with
0.0134 M NaOH (aq). It took 23.9 mL of the base to reach the
endpoint of the titration. What was the initial concentration of
H2SO4?
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22. Which of the following molecules would have the highest vapor
pressure at room temperature (22°C)?
A. 0.0102 M
B. 0.00508 M
A. H2O
C. 0.0204 M
B. C20H42 (all carbons in a single chain)
D. 0.102 M
C. HOCH2CH2OH
E. 0.227 M
D. C5H12 (all carbons in a single chain)
E. CH3CH2OH
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25. A can of soda has 40g of glucose (C6H12O6). Given that your
body combusts fuel, how much energy is produced, when your
body burns the glucose in a can of soda? Use the following heats
of formation.
27. For the following reaction, #H° = 2816 kJ:
H2O: #H°f = –285.8 kJ/mol
6 CO2(g) + 6 H2O(!)
C6H12O6(s) + 6 O2(g)
Which one of the following statements about this equilibrium is true?
A. Increasing PCO2 will cause it to shift to the left.
CO2: #H°f = –393.5 kJ/mol
B. Increasing temperature will cause it to shift to the left.
C6H12O6: #H°f = –1273 kJ/mol
C. Decreasing the total pressure by increasing the volume at
constant temperature will have no effect.
A. 1188 kJ
B. 132 kJ
D. Removing part of the C6H12O6 will cause it to shift to the
right.
C. 622 kJ
E. Adding a catalyst will cause it to shift to the left.
D. 433 kJ
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E. 1244 kJ
28. At 400 K, the equilibrium constant for the reaction is Kp = 7.0
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Br2(g) + Cl2 (g)
2BrCl(g)
26. Given the following bond enthalpies, estimate #H° for the
complete combustion of one mole of ethane (C2H6) in oxygen.
A closed vessel at 400 K is charged with 1.00 atm of Br2(g), 1.00
atm of Cl2(g), and 2.00 atm of BrCl(g). Use Q to determine which
of the statements below is true.
336 kJ/mol O$H
356 kJ/mol O2
416 kJ/mol C=O
598 kJ/mol
A. The equilibrium partial pressures of Br2(g), Cl2(g), and
BrCl(g) will be the same as the initial values.
C$O
C$C
C$H
C=C
467 kJ/mol
498 kJ/mol
803 kJ/mol
A. –1419 kJ/mol
B. –648 kJ/mol
C. +648 kJ/mol
D. –2838 kJ/mol
E. None of these are correct to within 1% of the answer.
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B. The equilibrium partial pressure of Br2(g) will be greater
than 1.00 atm.
C. At equilibrium, the total pressure in the vessel will be less
than the initial total pressure.
D. The equilibrium partial pressure of BrCl(g) will be greater
than 2.00 atm.
E. The reaction will go to completion since there are equal
amounts of Br2(g) and Cl2(g).
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29. Two moles of silver nitrate are mixed with one mole of Mg metal
and these are allowed to react to completion. What is the electron
configuration of the Mg species in the products?
31. Using an electrolysis set-up, you decompose water (#Hf = –285.8
kJ/mol) into hydrogen gas and oxygen gas. If you collect 12.2 L of
oxygen at 1 atm and 25° C, how much energy did you consume?
A. [Ne]
A. 35.73 kJ
B. [Ar]
B. 71.45 kJ
C. [Ne] 3s1
C. 142.9 kJ
2
D. 285.8 kJ
D. [Ne] 3s
E. [Kr] 5s2d9
E. 571.6 kJ
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30. Exactly 3.5 moles of N2O4(g) is placed in an empty 2.0-L
container and allowed to reach equilibrium described by the
equation
N2O4(g)
2NO2(g)
If at equilibrium, 2.625 moles of N2O4(g) remain, what is the
value of the equilibrium constant (Kc) for the reaction?
A. 0.17
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32. What is the heat of formation for methane in the gas phase given
the following reaction enthalpies?
CH4(g) + 2O2(g) " CO2(g) + 2H2O(g)
!H = –810 kJ/mol
C(s) + O2(g) " CO2(g)
!H = –394 kJ/mol
2H2(g) + O2(g) " 2H2O(!)
!H = –572 kJ/mol
H2O(!) " H2O(g)
!H = 40.7 kJ/mol
B. 0.33
C. 0.58
A. –6 kJ/mol
D. 0.67
B. –35 kJ/mol
E. 1.17
C.
35 kJ/mol
D. –75 kJ/mol
E.
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75 kJ/mol
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33. If 1.0 mol of N2 and 1.0 mol of O2 are mixed in a 1.0–liter
container and undergo the following reaction at a given
temperature:
35. A titanium-sapphire laser is tuned to " = 900 nm and used to image
the distribution of a dye in cultured cells. How many photons can
be captured by the cells before they absorb 12 J of heat?
N2 (g) + O2 (g)
2 NO (g)
Kc = 1.0
What will be the concentration of NO once equilibrium is reached?
A. 0.25 M
A. 2.2 ! 10–19
B. 1.3 ! 105
C. 1.6 ! 106
B. 0.33 M
D. 5.4 ! 1019
C. 0.50 M
E. 5.4 ! 1028
D. 0.66 M
E. 1.0 M
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34. A mixture contains 76.5% NaCl, 6.5 % MgCl2, and 17.0%
Na2SO4 by mass. What is the molarity of Cl– ion in a solution
formed by dissolving 7.5 g of the mixture in enough water to form
500 mL of solution?
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36. The boiling point elevation constant of water is 0.51 °C/m. If a
4.9 m solution of compound X with water has a boiling point of
110 °C, what could compound X be?
A. Na2CO3
A. 0.196 M
B. NH4Cl
B. 0.216 M
C. HClO2
C. 0.020 M
D. (NH4)3PO4
D. 0.200 M
E. Al2(SO4)3
E. 0.015 M
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37. Nicotine, a component of tobacco, is composed of C, H, and N.
A 5.250 mg sample of nicotine was combusted, producing 14.242
mg of CO2 and 4.083 mg of H2O. What is the empirical formula
of nicotine?
39. Given that the three standard reactions shown below proceed as
written, which of the subsequent 3 reactions do not occur.
A. C3H4N
Standard reactions
Mg(s) + ZnCl2(aq) " Zn(s) + MgCl2(aq)
Zn(s) + FeCl2(aq) " Fe(s) + ZnCl2(aq)
B. C5H7N
Fe(s) + CuCl2(aq) " Cu(s) + FeCl2(aq)
C. C7H6N2
D. C10H14N
I.
Mg(s) + FeCl2(aq) " Fe(s) + MgCl2(aq)
E. C5H5N
II.
Zn(s) + CuCl2(aq) " Cu(s) + ZnCl2(aq)
III.
Fe(s) + ZnCl2(aq) " Zn(s) + FeCl2(aq)
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38. What is the theoretical yield of NO(g) if 2.00 g of NH3(g) is
reacted with 2.75 g of O2(g) in the following reaction (which
needs to be balanced)?
NH3(g) + O2(g) #
NO(g) +
H2O(g)
A. I only
B. II only
C. III only
D. I and II
E. I and III
A. 3.53g
B. 0.88 g
C. 2.58 g
D. 2.06g
E. 0.52 g
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CHEMISTRY 110 FINAL EXAM
DECEMBER 12, 2011
Answer Key
40. CCl2F2 was previously used as a refrigerant but is now replaced by
compounds that are believed to be less harmful to the environment.
What mass of this substance must evaporate (at constant T) in order
to freeze 2 moles of water at 20 °C to ice at 0 °C?
The heat of vaporization of CCl2F2 is 289 J/g,
the heat of fusion of water is 334 J/g , and
the specific heat of water is 4.18 J/g-K.
A. 52.0 g
B. 26.0 g
C. 15.0 g
D. 3.01 g
E. 2.89 g
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END OF EXAM
FORM A
1. E
2. E
3. B
4. E
5. E
6. A
7. A
8. C
9. B
10. C
11. C
12. D
13. C
14. D
15. A
16. E
17. C
18. A
19. B
20. A
21. C
22. D
23. B
24. B
25. C
26. A
27. C
28. D
29. A
30. C
31. D
32. D
33. D
34. B
35. D
36. D
37. B
38. D
39. C
40. A