Chem 6A Section D, 2010 (Sailor)
Final Exam
INSTRUCTIONS:
(1) Write your name in the blank titled "NAME" on the scantron form provided.
(2) Write your section number in the blank titled "SUBJECT" on the scantron form.
(3) Write your Student ID number in the blanks titled "ID NUMBER" on the scantron form. Use
“1” in place of the “A” in your ID number.
(4) Fill in BOX XX in the "TEST FORM" box on the scantron form.
(5) Put your name HERE:______________________________________
(6) Perform all your scratch work on this test and hand in with the scantron form at the end of
the exam.
You are allowed to use a calculator and one 5x7 index card of notes (both sides).
1
18
1
H
2
2
1.0079
3
13
14
4
5
6.941 9.01218
11
12
10.811
13
Li
Be
Na Mg
22.9898
19
24.305
20
K
Ca
39.0983
37
Rb
85.4578
55
Cs
B
3
4
21
22
Sc
Y
87.62 88.9059
56
57
Ba
La
Ra
8
25
9
26
Cr Mn
10
27
Fe
Co
47.88 50.9415 51.9961 54.9381
40
41
42
43
55.847 58.9332
44
45
Zr
Ru
Nb Mo Tc
Hf
Ta
178.49 180.948
104
105
Rh
101.07 102.906
76
77
W
Os
Re
Ir
190.2
108
192.22
109
29
Ni
Cu
58.69
46
63.546
47
Pd
95.94 98.9063
74
75
183.85 186.207
106
107
28
11
Ag
12
Al
6
C
16
7
N
65.39
48
Si
P
69.723
49
Ge
As
72.61 74.9216
50
51
In
Sn
Sb
106.42 107.868 112.411
78
79
80
114.82
81
118.71
82
121.75
83
Pt
Tl
Pb
Au
195.08 196.967
Cd
Ga
Hg
200.59 204.383
58
Lanthanides
207.2
O
9
F
59
60
61
62
63
64
65
Pr
Nd Pm Sm Eu
Gd
Tb
140.12
90
140.91
91
144.24
92
157.25
96
158.92
97
Th
Pa
232.038
231.04
U
238.03
146.92
93
150.35
94
151.96
95
66
67
Dy Ho
162.5
98
Bi
S
Cl
Se
Br
Kr
78.96
52
79.904
53
Te
I
Po
At
168.93
101
174.97
103
Fm Md No
Cf
Es
254.09
1
Emitted power (W)
Tλmax = C2
= (constan t)T 4
e = mc 2
c = λν
5
Surface area (m2 )
1
 Z2 
1
1
hc
= RH  2 − 2 
E = hν
E=
E(in Joules) = −2.18 ×10−18  2 
λ
λ
n 
 n1 n 2 
1
71
167.26
100
251.08
249.08
70
164.93
99
Pu Am Cm Bk
247.07
69
Lu
239.05
257.1
83.8
54
Xe
127.6 126.905
84
85
Tm Yb
237.05
241.06
68
Ar
39.948
36
Er
Np
Ne
32.066 35.4527
34
35
-
Ce
4.0026
10
131.29
86
Rn
208.98 208.982 209.987 222.018
258.1
Some useful constants and relationships:
Specific heat capacities (in J/g.K): H2O(l) = 4.184; Al(s) = 0.900; Cu(s) = 0.387; Steel(s) = 0.45
101.325 J = 1 L.atm
1 atm = 760 Torr
1J = 1kg.m2/s2
1 eV = 1.6022 x 10-19J
.
.
-1 . -1
.
-1 . -1
R = Ideal gas constant: 0.08206 L atm mol K = 8.31451 J mol K
Avogadro constant: 6.022 x 1023 mole-1
Planck's constant = h = 6.6261 x 10-34 J.s
8
c = speed of light: 3.00 x 10 m/s
RH = 1.097 x 10-2 nm-1
-2
.
C2 = second radiation constant = 1.44 x 10 K m
€
8
12.011 14.0067 15.9994 18.9984 20.1797
14
15
16
17
18
26.9815 28.0855 30.9738
30
31
32
33
Zn
He
17
Ac
223.02 226.025 227.028 -
Actinides
7
24
V
91.224 92.9064
72
73
132.905 137.327 138.906
87
88
89
Fr
6
23
Ti
40.078 44.9559
38
39
Sr
5
15
173.04
102
255
Lr
262.1
Chem 6A Section D, 2010 (Sailor)
1.
Final Exam
Iridium exists in two isotopes, 191Ir (atomic mass 190.9609 amu) and 193Ir (atomic mass
192.9633 amu). If the average atomic mass of Ir is 192.2144 amu, what is the percent
abundance of 191Ir?
a) 39.47%
b) 37.40%
c) 47.84%
d) not enough information is given
e) none of the above
ANSWER: B 37.40%
2.
Which of the following reactions is the least endothermic?
a) Si(g) → Si+(g) + eb) P(g) → P+(g) + ec) S(g) → S+(g) + ed) Cl(g) → Cl+(g) + ee) Ar(g) → Ar+(g) + eANSWER: A
3.
Consider the reaction:
2NO(g) + O2(g) → 2NO2(g)
Identify the reducing agent in this reaction.
a) NO
b) O2 and NO2
c) O2
d) NO2
e) none of the above
ANSWER: A
4.
Consider the reaction of chlorine atoms responsible for depleting ozone in the stratosphere:
Cl(g) + O3(g) → ClO(g) + O2(g)
If 5 moles of O3 are consumed in this reaction, how many moles of O2 are produced?
a) 5
b) 7.5
c) 2
d) 3
e) none of the above
ANSWER: A
2
Chem 6A Section D, 2010 (Sailor)
5.
Final Exam
Which of the following compounds has the most covalent bond character?
a) HF
b) HBr
c) HCl
d) HI
e) KF
ANSWER: D
6.
Which of the following compounds are paramagnetic (check all that apply)?
7.
a) NO2
b) O3
c) NO
d) N2
e) CF2Cl2
ANSWER: A and C are paramagnetic
What is the value of the F-P-F bond angle (θ) in PF3?
8.
a) 120° < θ < 180°
b) 109.5° < θ < 120°
c) 90° < θ < 109.5°
d) 60° < θ < 90°
e) θ = 120°
ANSWER: C (actual value is 96.3°)
What is the oxidation number of bromine in BrF5?
a) -1
b) +4
c) +5
d) +7
e) none of the above
ANSWER: C +5
9.
A coin of mass 1.670 g is dropped into a graduated cylinder containing 20.000 mL of
water. The volume of the water level rises to 21.247 mL. What is the density of the coin?
a) 1.339 g/mL
b) 0.0786 g/mL
c) 0.0835 g/mL
d) 1.247 g/mL
e) none of the above
ANSWER: A
3
Chem 6A Section D, 2010 (Sailor)
10.
Final Exam
The transition of an electron from the principle quantum number n = 4 to n = 2 in atomic
hydrogen causes emission of a photon of what wavelength?
a) 1117 nm
b) 1094 nm
c) 365 nm
d) 486 nm
e) none of the above
ANSWER: D
11.
The molecular formula for a compound is C12H16N4O8, and its molar mass is 344.28 g/mol.
What is the molar mass of the empirical formula of this compound?
a) 344.28 g/mol
b) 688.56 g/mol
c) 1377.12 g/mol
d) 172.14 g/mol
e) none of the above
ANSWER: E it is 86.07 for C3H4NO2
12.
How many unpaired electrons are there in a ground state atom of Fe(g)?
a) 0
b) 8
c) 4
d) 5
e) none of the above
ANSWER: C
13.
How many unpaired electrons are there in a ground state ion of Fe3+(g)?
a) 0
b) 8
c) 4
d) 5
e) none of the above
ANSWER: D
14.
A sample of Li2 molecules contains only two isotopes of lithium, 5Li and 7Li. At what amu
values will the peaks in the mass spectrum of this sample occur?
a) 5 and 7 amu
b) 5, 6, and 7 amu
c) 10, 12, and 14 amu
d) 10, 11, 12, 13, and 14 amu
e) 12, 13, and 14 amu
ANSWER: C
4
Chem 6A Section D, 2010 (Sailor)
15.
16.
Final Exam
What volume of an aqueous solution 0.038 M in KMnO4 contains 0.0010 mol of potassium
ions?
a) 26 mL
b) 325 mL
c) 38 mL
d) 0.038 mL
e) none of the above
ANSWER: A
For the following Lewis structure, considering the atoms from left to right, the formal
charges on N, C, and O, respectively, are
a) +5, +4, +6
b) -5, -4, -6
c) +1, 0, -2
d) 0, 0, -1
e) none of the above
ANSWER: D
17.
What is the bond order of the N-O bonds in the nitrate ion (NO3-)?
a) 1 or 2
b) 120°
c) 1.333
d) resonance
e) none of the above
ANSWER: C
18.
What is the balanced net ionic equation for the reaction that occurs when aqueous copper
(II) chloride is added to aqueous lithium sulfide?
a) CoCl2(aq) + Li2Saq) → Co2+(aq) + 2Li+(aq) + 2Cl-(aq) + S2-(aq)
b) Cu+(aq) + S2-(aq) → Cu2S(s)
c) Co2+(aq) + S2-(aq) → CoS(s)
d) Co+(aq) + S2-(aq) → Co2S(s)
e) none of the above
ANSWER: E (it is Cu2+(aq) + S2-(aq) → CuS(s))
5
Chem 6A Section D, 2010 (Sailor)
19.
Final Exam
What is the electron configuration of the (gas phase) Fe2+ ion?
a) [Ar] 4s2 3d4
b) [Ar] 4s2 3d6
c) [Ar] 4s2 3d8
d) [Ar] 3d6
e) [Ar] 4s2 3d10 4p6
ANSWER: D
20. The set of quantum numbers n = 4, l = 1, ml = 0 and ms =+1/2 describes an electron in
which orbital?
a) 4f
b) 4d
c) 4p
d) 4s
e) none of the above
ANSWER: C
21. Which of the following gas phase atoms or ions is paramagnetic (check all that apply)?
a) H
b) He
c) V2+
d) O
e) Mg
ANSWER: A, C, and D
22. Which of the following has 5 protons, 3 neutrons, and 5 electrons?
23.
a) 5B2b) 7B
c) 10B
d) 8B2e) none of the above
ANSWER: E (it is 8B)
When the following reaction is balanced, 5 moles of KClO3 reacting with excess C will
produce how many moles of CO2?
2KClO3 + 3C → 3CO2 + 2KCl
a) 3
b) 3.33
c) 5
d) 7.5
e) none of the above
ANSWER: D
6
Chem 6A Section D, 2010 (Sailor)
24.
25.
Final Exam
83.0 g of NaClO4 is diluted to the mark with water in a 500.0 mL volumetric flask. What
is the concentration, in molarity, of the solution?
a) 1.36 x 10-2 M
b) 0.166 M
c) 4.07 M
d) 0.294 M
e) none of the above
ANSWER: E it is 1.36 M
The number of grams of F in 50.0 g of NaBF4 is
a) 34.6 g
b) 8.65 g
c) 0.626 g
d) 69.2 g
e) none of the above
ANSWER: A
26.
Which of the following is the most plausible structure for the PCl4+ ion:
a)
b)
d)
e)
c)
ANSWER: C
27.
Which is the most plausible geometry for the XeF4 molecule (electron lone pairs are not
shown)?
a)
b)
c)
e)
ANSWER: B
7
d)
Chem 6A Section D, 2010 (Sailor)
28.
Final Exam
Which is the most plausible Lewis structure for thiocyanate? The Pauling
electronegativities of S, C, and N are 2.5, 2.5, and 3.0, respectively
a)
b)
d)
e)
c)
ANSWER: A
29.
Aspirin contains only C, H, and O. Combustion analysis of a 4.00 g sample produces
1.600 g of water and 8.794 g of CO2. What is the empirical formula of this compound?
a) C9H8O4
b) C3H2O
c) C6H3Cl2
d) C10H6O2
e) none of the above
ANSWER: A
30.
The balanced equation for the reaction that occurs when SO2 dissolves in water is:
a) 3SO2 + H2O → 2HSO3 + SO
b) SO2 + H2O → H2SO3
c) 3SO2 + H2O → HSO3 + H+ + S2
d) SO2 + H2O → HSO2 + OHe) none of the above
ANSWER: B
31.
Which of the following is a strong acid (check all that apply)?
a) HCl
b) CH3COOH
c) HClO4
d) HNO3
e) HF
ANSWER: A, C, and D
8
Chem 6A Section D, 2010 (Sailor)
32.
Final Exam
What is the molecular weight (mass) of ferrocene, Fe(C5H5)2?
a) 186.0
b) 120.9
c) 68.87
d) 96
e) none of the above
ANSWER: A
33.
What is the oxidation state of boron in boron trifluoride?
34.
a) 0
b) +1
c) +2
d) +3
e) none of the above
ANSWER: D
Consider the combustion of benzene:
2C6H6(g) + 15O2(g) → 12CO2(g) + 6H2O(l)
If 25.0 g of benzene is mixed with 18.0 g of O2(g) and allowed to react, how much CO2 will
be produced?
35.
36.
a) 43.0 g
b) 28.7 g
c) 84.5 g
d) 19.8 g
e) none of the above
ANSWER: D
If 5 moles of chlorine gas are reacted with 4 moles of sodium to make sodium chloride,
which of the following statements is true (check all that apply)?
a) chlorine is the limiting reagent, 1 mole of sodium will be left after the reaction
b) sodium is the limiting reagent, 1 mole of chlorine will be left after the reaction
c) chlorine is the limiting reagent, 6 moles of sodium will be left after the reaction
d) sodium is the limiting reagent, 3 moles of chlorine will be left after the reaction
e) the reaction is stoichiometric, all of the sodium and chlorine are consumed
ANSWER: D
Which molecule is expected to be the most polar?
a) CO2
b) O2
c) CH4
d) SnCl2
e) PCl5
ANSWER: D
9
Chem 6A Section D, 2010 (Sailor)
37.
Final Exam
An aqueous solution labeled "potassium permanganate" contains the ions:
a) K+ and MnO4b) P3+ and MnO3c) K+ and MnO2d) Pt2+ and MnO4e) none of the above
ANSWER: A
38.
How many grams of Na2SO4 are needed to make 500.0 mL of a 0.1788 M solution of
Na2SO4?
a) 0.500 g
b) 1.270 g
c) 0.0894 g
d) 0.3576 g
e) none of the above
ANSWER: E (12.70 g are needed)
39.
Which of the following has the highest (most endothermic) first ionization energy?
a) Be
b) B
c) C
d) N
e) O
ANSWER: D
40.
The typical wavelength of UV-B ultraviolet light is 300 nm. Which of the following
bonds can be broken by a single photon of this energy (average bond energies are given
next to each bond)? Check all that apply.
a) C-N (305 kJ/mol)
b) C-O (358 kJ/mol)
c) C=O (745 kJ/mol)
d) N≡N (945 kJ/mol)
e) none of the above
ANSWER: A and B (the energy works out to 400 kJ/mol)
10
Chem 6A Section D, 2010 (Sailor)
41.
Final Exam
Which of the following ions has the largest radius?
a) K+
b) Ca2+
c) As3d) Se2e) BrANSWER: C
42.
What is the energy needed to ionize (completely remove an electron from) a hydrogen
atom?
a) 91.2 nm
b) 121.6 nm
c) -121.6 nm
d) 1.84 nm
e) none of the above
ANSWER: A (OK if they put E; problem worded wrong—asking for E not wavelength)
43.
Consider the reaction:
2CO(g) + 2NO(g) → 2CO2(g) + N2(g)
In the balanced equation, how many moles of N2 are produced per mole of CO reacted?
a) 0
b) 0.67
c) 1
d) 1.5
e) none of the above
ANSWER: E (it is 0.5)
44.
Which compound below contains 39.2 % Cl by mass?
a) NaCl
b) NaClO
c) NaClO2
d) NaClO3
e) NaClO4
ANSWER: C
11
Chem 6A Section D, 2010 (Sailor)
45.
Final Exam
The Direct Process, also called the Rochow Process, is the most common method used to
prepare organosilicon compounds such as silicone on an industrial scale. It uses an alkyl
halide and elemental silicon as reactants. One balanced reaction for the process is:
2CH3Cl(g) + Si(s) → (CH3)2SiCl2 (s)
If 50.0 g of CH3Cl are reacted with excess Si and 33.0 g of (CH3)2SiCl2 are produced, what
is the percent yield of the reaction?
a) 63.9 %
b) 66.0 %
c) 25.8 %
d) 51.6 %
e) none of the above
ANSWER: D
46.
In the following reaction:
2KClO3 + 3C → 3CO2 + 2KCl
How many moles of electrons does 1 mole of the KClO3 oxidizing agent receive?
a) 2
b) 4
c) 6
d) 8
e) none of the above
ANSWER: C
47.
48.
What is q in Joules when 35.0 g of liquid water is heated from 25.0°C to 80.0°C?
a) 8050 J
b) 1930 J
c) 15,400 J
d) 8000 J
e) none of the above
ANSWER: A
Calculate the enthalpy change (ΔH) in the combustion of 0.953 kg of ethanol, given the
standard enthalpy of combustion of ethanol (C2H6O(l)) is -1398 kJ/mol. The reaction is:
CH3CH2OH(l) + 3O2(g) → 2CO2(g) + 3H2O(l)
a) -28,900 kJ
b) -303,000 kJ
c) -1332 kJ
d) -103.2 kJ
e) none of the above
ANSWER: A
12
Chem 6A Section D, 2010 (Sailor)
49.
Final Exam
Given the following thermochemical data:
Process
Enthalpy, kJ/mol
Ca(s) → Ca(g)
∆Hf (Ca(g))= +178
S(s) → S(g)
∆Hf (S(g))= +279
Ca2+(g) + 2e- → Ca(g)
∆Hrxn = -1735
Ca+(g) + e- → Ca(g)
∆Hrxn = -590
S(g) + 2e- → S2-(g)
∆Hrxn = 332
S(g) + e- → S-(g)
∆Hrxn = -200
Ca(s) + S(s) → CaS(s)
∆Hf (CaS(s))= -482
What is the enthalpy change for the following reaction:
Ca2+(g) + S2-(g) → CaS(s)
ΔH° = ?
a) -3006 kJ
b) -1628 kJ
c) -1610 kJ
d) -207 kJ
e) none of the above
ANSWER: A
50.
A table of bond energies is given below. From this data, what is ΔH°rxn for the chlorination of
methane (CH4) to form chloroform (HCCl3), shown below.
Average Bond Energies, kJ/mol
Bond
Energy
Bond
Energy
H-H
H-Cl
C-H
C-C
O=O
432
427
413
347
498
C=O (for CO2)
C=O
Cl-Cl
C-Cl
O-H
799
745
243
339
467
a) +83 kJ
b) -1430 kJ
c) -330 kJ
d) -207 kJ
e) none of the above
ANSWER: C
13
Chem 6A Section D, 2010 (Sailor)
51.
Final Exam
Which of the following song titles best describes your experience with Chem 6A?
a) “Tell Me Why” –Taylor Swift
b) “Bad Romance” – Lady GaGa
c) “Hot N Cold” –Katy Perry
d) “Double Rainbow” –The Gregory Brothers
e) none of the above (write-in on back of scantron form)
14