CHEMISTRY 110 EXAM 4
Dec.13, 2010
FORM A
-----------------------------------------------------------------------------------------1. Which of the following atoms or ions has the correct number of
protons, neutrons, and electrons shown?
Atom
13
A
Protons
Neutrons
Electrons
C
12
13
12
Na+
11
23
10
17
19
18
B
23
C
36
D
82
Kr
41
41
41
E
1
H
1
0
0
Cl−
-----------------------------------------------------------------------------------------2. The value of Keq for the equilibrium below is 794 at 25 °C.
H2(g) + I2(g)
2 HI(g)
At this temperature, what is the value of Keq for the following reaction?
HI(g)
½ H2(g) + ½ I2(g)
A. 1588
B. 28
C. 397
D. 0.035
E. 0.0013
------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------3. What neutral atom in its ground state is described by the following
electron configuration?
1s2 2s2 2p6 3s2 3p6 4s1 3d5
A. Cr
B. Mn
C. Cl
D. K
E. V
-----------------------------------------------------------------------------------------4. Which of these sets of quantum numbers is allowed?
n
A.
B.
C.
D.
E.
2
3
5
4
1

0
4
3
3
2
m
−1
0
1
−2
3
ms
+1/2
−1/2
0
+1/2
−1/2
-----------------------------------------------------------------------------------------5. How many lone pairs are found in the best Lewis structure of CO2?
A.
B.
C.
D.
E.
6
4
3
2
0
------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------6. Which of the following is the correct empirical formula of the
molecule shown below?
A. C14H8O2
B. C7H4O
C. C14H12O2
D. C7H6O
E. C7H7O
-----------------------------------------------------------------------------------------7. What is the enthalpy change when a 4.0 gram sample of aluminum
burns in excess of oxygen to form aluminum oxide?
4 Al(s) + 3 O2(g) → 2 Al2O3(s) ΔH = −3351 kJ
A. −3351 kJ
B. −837.8 kJ
C. −124.2 kJ
D. +837.8 kJ
E. +3351 kJ
------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------8. Which one of the following is the most polar molecule?
Cl
Cl
Cl
Cl
A
B
C
D
E
-----------------------------------------------------------------------------------------9. An unknown element is found to have three naturally occurring
isotopes with atomic masses of 35.9675 (0.337%), 37.9627
(0.063%), and 39.9624 (99.600%). Which of the following is the
unknown element?
A. Ar
B. K
C. Cl
D. Ca
E. Al
-----------------------------------------------------------------------------------------10. Arrange the following in order of increasing lattice energy.
LiF, CsI, LiI, CaO
A. LiF < LiI < CsI < CaO
B. CaO < LiF < LiI < CsI
C. CsI < CaO < LiI < LiF
D. CsI < LiI < LiF < CaO
E. LiI < CsI < LiF < CaO
------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------11. An energy level diagram is shown below. If the electron moves
to the lowest energy state in the diagram, is a photon emitted or
absorbed and what is the energy of the photon?
−½RH
−¾RH
−RH
A. emitted; E = ½ RH
B. emitted; E = ¼ RH
C. emitted; E = RH
D. absorbed; E = ¼ RH
E. absorbed; E = ½ RH
------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------12. Energy to break 1 mole of H2 molecules into 2 moles of H atoms is
440 kJ/mol. What is the energy to break one H2 molecule into two
H atoms.
A. 7.3 × 10−19 J
B. 7.3 × 10−22 J
C. 1.4 × 1018 J
D. 1.4 × 1021 J
E. Insufficient information
-----------------------------------------------------------------------------------------13. Which one of these has a mass percentage of N equal to 82%?
A. CH3NH2
B. N2O4
C. NH3
D. NH4OH
E. N2
-----------------------------------------------------------------------------------------14. Which of the following is paired with a WRONG molecular
geometry?
A. CO2 : linear
B. SO2 : bent
C. NO3− : trigonal planar
D. NH3 : trigonal pyramidal
E. XeF4 : tetrahedral
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-----------------------------------------------------------------------------------------15. Which of the following molecules interact via hydrogen bonding
in the pure liquid state?
i.
C2H 6
ii.
NH3
iii.
CH3Cl
iv.
CH3OH
A. i and iii
B. ii and iv
C. i, ii and iii
D. iii and iv
E. ii, iii and iv
-----------------------------------------------------------------------------------------Use the information in the table below for questions 16 and 17.
Mole fraction
He
0.275
PTOT = 550 torr
Ne
0.232
VTOT = 8.50 L
Ar
0.213
T = 298 K
Kr
0.280
----------------------------------------------16. How many moles of Ne are in the mixture?
A.
B.
C.
D.
E.
0.0583 moles
0.168 moles
0.232 moles
0.251 moles
It is impossible to tell from the information given.
-----------------------------------------------
----------------------------------------------17. If the curves below show the distribution of speeds of the four
different gases in the mixture, which one of the curves corresponds to
argon?
A
B
Fraction of molecules
C
D
Molecular speed
A.
Curve A
B.
Curve B
C.
Curve C
D.
Curve D
E.
Since T is the same for all of the gases, the distribution of
speeds for all four gases should be the same.
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-----------------------------------------------------------------------------------------18. Which of the following is the correct orbital hybridization for O(1),
C(2) and N(3) as numbered below? Note: the lone pairs are NOT shown
explicitly.
NH2
HO
3
1
2
O (1)
C (2)
N (3)
A.
sp3
sp3
sp3
B.
sp2
sp3
sp3
C.
sp3
sp2
sp3
D.
sp
sp2
sp3
E.
sp
sp2
sp2
-----------------------------------------------------------------------------------------19. How many σ and π bonds are in CO?
A.
B.
C.
D.
E.
3 σ and 0 π
1 σ and 2 π
1 σ and 3 π
2 σ and 1 π
2 σ and 2 π
------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------20.
Considering the phase diagram shown above for an unspecified substance,
which of the following statements is true?
A. Process ‘C’ corresponds to evaporation
B. It is not possible to find the solid and gas in equilibrium at any
temperature.
C. The point labeled ‘G’ is the critical point.
D. The density of the liquid is less than the density of the solid
E. When the solid and liquid are at equilibrium, process ‘B’ stops
completely.
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-----------------------------------------------------------------------------------------21. Substance A has stronger intermolecular forces than substance B.
Both are liquids at room temperature. Which of the statements are
true for these liquids under the same conditions of temperature
and pressure?
1. The surface tension of A will be greater than the surface tension of B.
2. The vapor pressure of A will be greater than the vapor pressure of B.
3. The viscosity of A will be greater than the viscosity of B.
A.
B.
C.
D.
E.
1 only
2 only
3 only
1 and 3
1, 2, and 3
-----------------------------------------------------------------------------------------22. Which one of these would you expect to be least soluble in water?
O
OH
OH
O
NH2
OH
A
B
C
D
E
------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------23. Which of the following molecules would be expected to be a weak
electrolyte?
-----------------------------------------------------------------------------------------24. A chemist mixes each of the following pairs of chemicals in aqueous
solution. Which resulting reaction will NOT yield a precipitate?
A. ammonium sulfate and barium nitrate
B. calcium sulfate and sodium carbonate
C. lead (II) nitrate and sodium chloride
D. copper (II) chloride and sodium hydroxide
E. barium iodide and magnesium sulfide
-----------------------------------------------------------------------------------------25. When aqueous solutions of CoCl2 and AgNO3 are combined, which
ion(s) is/are spectator ions?
A. Co2+ and NO3−
B. NO3− and Cl−
C. Co2+ and Ag+
D. Cl−
E. NO3−
------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------26. What are the coefficients when the following equation is balanced?
NH3(g) + O2(g) → NO2(g) + H2O(g)
A. 1, 1, 1, 1
B. 4, 3, 4, 3
C. 2, 3, 2, 3
D. 1, 3, 1, 2
E. 4, 7, 4, 6
-----------------------------------------------------------------------------------------27. What mass of solid CaCl2 must be added to 1.50 L of a 0.100 M
AgNO3 solution to precipitate all of the silver ions?
A. 3.70 g
B. 5.55 g
C. 8.32 g
D. 11.1 g
E. 16.6 g
------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------28. What is the heat of reaction (ΔHrxno) for the complete combustion of
acetone (C3H6O) given the following thermochemical equations?
3 C(s) + 3 H2(g) + ½ O2(g) → C3H6O(l)
ΔHfo = −285.0 kJ/mol
C(s) + O2(g) → CO2(g)
ΔHfo = −394.0 kJ/mol
H2(g) + ½ O2(g) → H2O(l)
ΔHfo = −286.0 kJ/mol
A. −965 kJ
B. −1755 kJ
C. −395 kJ
D. +1222 kJ
E. + 450 J
-----------------------------------------------------------------------------------------29. Calculate the enthalpy for the unknown reaction at standard state
given the following enthalpies of formation.
CO2(g)
CO(g)
NO2(g)
ΔHof (kJ/mol)
−393.5
−110.5
33.84
2 NO2(g) + 4 CO(g) → N2(g) + 4 CO2(g)
ΔHorxn =???
A. −156.7 kJ
B. −1200 kJ
C. −470.0 kJ
D. −1948 kJ
E. You cannot determine ΔHorxn from the information given.
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-----------------------------------------------------------------------------------------30. Using the table of average bond energies below, what is the ΔH for
the following reaction?
C≡O(g) + 2 H2(g) → H3C−O−H(g)
Bond:
C−O
C=O
C≡O
C−H
H−H
O−H
D (kJ/mol):
358
799
1072
413
436
463
A.
+276 kJ/mol
B.
−276 kJ/mol
C.
+735 kJ/mol
D.
−735 kJ/mol
E.
−116 kJ/mol
-----------------------------------------------------------------------------------------31. When steam is passed over a bed of coke (a form of C) at 800 ˚C the
following reaction occurs. At equilibrium, [H2] = 4.0 × 10−2 M,
[CO] = 4.0 × 10−2 M, [H2O] = 1.0 × 10−2 M, and 10 g of coke
remain. What is Kc at this temperature?
C(s) + H2O(g)
A.
B.
C.
D.
E.
CO(g) + H2(g)
0.16
0.25
4
6.25
0
------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------32. In which of the following reactions would increasing pressure at
constant temperature not change the concentrations of reactants and
products, based on Le Chatelier's principle?
A. N2(g) + 3 H2(g)
2 NH3(g)
B. N2O4(g)
2 NO2(g)
C. N2(g) + 2 O2(g)
2 NO2(g)
D. 2 N2(g) + O2(g)
2 N2O(g)
E. N2(g) + O2(g)
2 NO(g)
-----------------------------------------------------------------------------------------33. Which of the following functional groups is NOT contained in the
molecule shown below?
A. Aldehyde
B. Amine
C. Carboxylic acid
D. Alcohol
E. Ketone
------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------34. A 200 g sample of limestone, CaCO3, is placed in a 10.0 L flask under
vacuum and heated to 900 °C, where it decomposes into lime (CaO)
and a gas. What is the average molecular speed of the resulting gas?
A. 69.4 m/s
B. 81.0 m/s
C. 698 m/s
D. 714 m/s
E. 815 m/s
-----------------------------------------------------------------------------------------35. GeF3H is formed from GeH4 and GeF4 according to the following
equation:
GeH4 + 3 GeF4 → 4 GeF3H
If the reaction yield is 92.6%, how many moles of GeF4 are needed
to produce 8.00 mol of GeF3H?
A. 3.24
B. 5.56
C. 6.48
D. 2.78
E. 2.16
------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------36. The temperature of 500.0 g water contained in a calorimeter increased
from 20.0 oC to 50.0 oC when 5.00 g of fuel was burned to
completion. What is the ΔH of this combustion reaction? (The
specific heat of water is 4.184 J/g oC and the molecular weight of the
fuel is 40.0 g/mol.)
A. −12 kJ/mol
B. −628 J/mol
C. −62.8 kJ/mol
D. −502 kJ/mol
E. −418 kJ/mol
-----------------------------------------------------------------------------------------37. Consider the following reaction:
2 NO(g) + 5 H2(g) → 2 NH3(g) + 2 H2O(g)
A reaction mixture contains 5 moles of NO and 10 moles of H2. What is
in the final reaction mixture after the reaction has gone to completion?
A.
B.
C.
D.
E.
NO(g)
1 mol
0 mol
3 mol
0 mol
0 mol
H2(g)
0 mol
1 mol
5 mol
0 mol
5 mol
NH3(g)
4 mol
5 mol
2 mol
4 mol
2 mol
H2O(g)
4 mol
5 mol
2 mol
4 mol
2 mol
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-----------------------------------------------------------------------------------------38. Methane reacts with oxygen to produce carbon dioxide and water.
When 16.0 g of methane is burned in a vessel that contained 32.0 g
of oxygen, what is the pressure in the vessel after complete
combustion? The volume of the vessel is 20.0 L and the temperature
of the vessel is 400 oC after the combustion.
A. 8.28 atm
B. 5.52 atm
C. 2.76 atm
D. 11.0 atm
E. 13.8 atm
-----------------------------------------------------------------------------------------39. Rank the following solutions in order of increasing freezing point.
i.
0.10 mole of NaCl in 500 mL of water
ii.
0.40 mole of glucose C6H12O6 in 500 mL of water
iii.
0.25 mole of CaCl2 in 500 mL of water
iv.
500 mL of water
A. i < ii< iii< iv
B. iv < iii < ii < i
C. iii < ii < i < iv
D. iv < ii < iii < i
E. ii < iii < i < iv
------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------40. The enthalpy of fusion of water is 6.0 kJ/mol and the heat capacity of
ice is 36.5 J/mol C. How many kJ of heat is given off when 5 mol of
liquid water at 0 ˚C is frozen to ice at −10 ˚C?
A.
B.
C.
D.
E.
30.5 kJ
26.3 kJ
21 kJ
78 kJ
31.8 kJ
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END OF EXAM
CHEMISTRY 110 FINAL EXAM
DECEMBER 13, 2010
Answer Key
FORM A
1. C
2. D
3. A
4. D
5. B
6. B
7. C
8. D
9. A
10. D
11. A
12. A
13. C
14. E
15. B
16. A
17. B
18. C
19. B
20. D
21. D
22. D
23. E
24. E
25. A
26. E
27. C
28. B
29. B
30. E
31. A
32. E
33. C
34. E
35. C
36. D
37. A
38. B
39. C
40. E