Download CHEM 13 NEWS EXAM 2004 - University of Waterloo

CHEM 13 NEWS EXAM 2004
UNIVERSITY OF WATERLOO
DEPARTMENT OF CHEMISTRY
12 MAY 2004
TIME: 75 MINUTES
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1
1A
1
H
1.008
3
Li
6.941
11
Na
22.99
19
K
39.10
37
Rb
85.47
55
Cs
132.9
87
Fr
(223)
2
2A
4
Be
9.012
12
Mg
3
4
24.31
3B
4B
20
21
22
Ca
Sc
Ti
40.08
44.96 47.88
38
39
40
Sr
Y
Zr
87.62
88.91 91.22
56
(57-71)
72
Ba
La-Lu
Hf
137.3
178.5
88
(89-103) 104
Ra
Ac-Lr
Rf
(226)
5
5B
23
V
50.94
41
Nb
92.91
73
Ta
180.9
105
Db
6
6B
24
Cr
52.00
42
Mo
95.94
74
W
183.9
106
Sg
7
7B
25
Mn
54.94
43
Tc
(98)
75
Re
186.2
107
Bh
8
←
26
Fe
55.85
44
Ru
101.1
76
Os
190.2
108
Hs
9
8B
27
Co
58.93
45
Rh
102.9
77
Ir
192.2
109
Mt
10
→
28
Ni
58.69
46
Pd
106.4
78
Pt
195.1
110
Uun
11
1B
29
Cu
63.55
47
Ag
107.9
79
Au
197.0
111
Uuu
12
2B
30
Zn
65.38
48
Cd
112.4
80
Hg
200.6
112
Uub
13
3A
5
B
10.81
13
Al
26.98
31
Ga
69.72
49
In
114.8
81
Tl
204.4
113
Uut
14
4A
6
C
12.01
14
Si
28.09
32
Ge
72.59
50
Sn
118.7
82
Pb
207.2
15
5A
7
N
14.01
15
P
30.97
33
As
74.92
51
Sb
121.8
83
Bi
209.0
16
6A
8
O
16.00
16
S
32.07
34
Se
78.96
52
Te
127.6
84
Po
(209)
17
7A
9
F
19.00
17
Cl
35.45
35
Br
79.90
53
I
126.9
85
At
(210)
18
8A
2
He
4.003
10
Ne
20.18
18
Ar
39.95
36
Kr
83.80
54
Xe
131.3
86
Rn
(222)
1
2
Which one of the following compounds has the
lowest boiling point?
4
A
CH3F
A
butanoic acid
B
CH3CH3
B
butanal
C
CH3OH
D
CH3NH2
C
2-butanone
E
CH3CH2CH3
D
diethyl ether
E
ethyl ethanoate
What is the maximum mass of iron, Fe, that can
be obtained from a reaction mixture containing
2.5 g Al and 9.5 g Fe2O3? The balanced
chemical equation is given below.
5
2 Al(s) + Fe2O3(s) → Al2O3(s) + 2 Fe(s)
A
6.6 g
B
10.4 g
C
5.2 g
D
1.7 g
E
3.3 g
MgCl2, ICl3, P4O10
Molar masses (in g mol )
B
KBr, C2H6, SF4
Al
Fe2O3
Al2O3
Fe
C
C6H6, Al(NO3)3, SO3
D
CO, HOCN, O3
E
K2O, HF, NH3
26.98
159.7
101.96
55.85
Which functional groups are present in the
molecule below?
O
H C
Which of the following is properly classified as a
set of covalent compounds?
A
-1
6
3
Which one of the following is an isomer of
1-butanol?
O
CH2 O CH2 C CH2CH3
A
aldehyde and ketone
B
ester and aldehyde
C
ether and ketone
D
ester, ketone and ether
E
aldehyde, ether and ketone
7
2 / CHEM 13 NEWS EXAM © 2004 UNIVERSITY OF WATERLOO
What is the net ionic equation for the reaction of
HCl(aq) with NaOH(aq)?
A
H+(aq) + OH−(aq) → H2O(l)
B
Na+(aq) + Cl−(aq) → NaCl(s)
C
Cl−(aq) + OH−(aq) → OCl−(aq) + H−(aq)
D
HCl(aq) + Na+(aq) → NaCl(s) + H+(aq)
E
HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
What is ∆H o for the reaction below?
PCl5(g) + 4 H2O(l ) → H3PO4(s) + 5 HCl(g)
A
-688.6 kJ
B
-200.1 kJ
C
-74.9 kJ
D
-1000.6 kJ
E
-900.3 kJ
-
∆H fo (in kJ mol 1)
PCl5(g)
H2O(l )
H3PO4(s)
HCl(g)
-398.9
-285.9
-1281.1
-92.30
8
9
What mass of copper solid, initially at 25oC,
should be added to 100 g of steam, initially at
100oC, if we want exactly half of the steam to
condense?
A
30 g
B
1.1 kg
C
1.5 kg
D
2.2 kg
E
3.9 kg
10
Which of the following reactions are oxidationreduction reactions?
(i) H2CO3(aq) → H2O(l) + CO2(g)
(ii) 2 Li(s) + 2 H2O(l) → 2 LiOH(aq) + H2(g)
The specific heat of copper
is 0.385 J g-1 oC-1.
(iii) 4 Ag(s) + PtCl4(aq) → 4 AgCl(s) + Pt(s)
For water, the heat of
vaporization is 2257 J g−1.
(iv) 2 HClO4(aq) + Ca(OH)2(aq)
→ 2 H2O(l) + Ca(ClO4)2(aq)
A
i and iii
B
ii and iii
C
ii and iv
D
iii and iv
E
i, ii, iii and iv
The reaction profile for a two-step reaction is
shown below.
11
b
Potential
Energy
c
a
What is the ground-state electron configuration of
an isolated cobalt (Co) atom ?
d
e
Reaction Coordinate
A
[Ar] 4s 2 4d 7
B
[Ar] 4s 1 3d 5 4p 3
C
[Ar] 4s 2 4p 6 4d 1
D
[Ar] 4s 2 3d 7
E
[Ar] 3d 9
Which quantity is the most important for
determining the rate of the forward reaction?
A
a
12
B
b
Based on the relative positions of H, C, N, O, P
and S in the periodic table, which of the following
covalent bonds is the most polar?
C
c
A
H-C
D
d
B
H-N
E
e
C
H-O
D
H-P
E
H-S
© 2004 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 3
13
The reaction below was carried out several times
in order to determine the rate equation.
16
A soluble salt affects the freezing and boiling
points of water of water in which of the following
ways?
X(aq) + Y(aq) → products
i.
ii.
iii.
iv.
Experiments revealed that the rate doubled when
the concentration of X was doubled and that the
rate increased by a factor of eight when the
concentration of Y was doubled. What is the rate
equation?
A
Rate = k [X] [Y]4
A
ii and iii only
B
2
Rate = k [X] [Y]
B
i and iii only
C
Rate = k [X] [Y]3
D
E
C
ii and iii only
2
3
D
ii and iv only
2
8
E
i and iv only
Rate = k [X] [Y]
Rate = k [X] [Y]
17
14
15
It lowers the freezing point.
It raises the freezing point.
It lowers the boiling point.
It raises the boiling point.
A
two σ bonds, two π bonds and a bond
angle of 120o
Carbon and silicon are group 14 elements, and
form oxides CO2 and SiO2, respectively. Carbon
dioxide is a gas at room temperature and normal
atmospheric pressure, while SiO2 is a solid that
melts at about 1700oC. Why is there such a great
difference in the physical properties of these two
oxides?
B
two σ bonds, no π bonds and a bond
angle of 180o
A
C
two σ bonds, no π bonds and a bond
angle of 109o
CO2 is a molecular compound and SiO2 is an
ionic compound.
B
D
two σ bonds, two π bonds and a bond
angle of 180o
The carbon-oxygen bond in CO2 is much
weaker than the silicon-oxygen bond in SiO2.
C
E
four σ bonds, no π bonds and a bond
angle of 180o
CO2 is a molecular compound and SiO2 is a
metallic solid.
D
The carbon-oxygen bond in CO2 is much less
polar than the silicon-oxygen bond in SiO2.
E
CO2 is a molecular compound and SiO2 is a
network covalent solid.
Which of the following correctly characterizes the
bonds and geometry of the CO2 molecule?
Which of the following molecules does not contain
a multiple bond?
A
N2H4
B
C2H2
C
HOCN
D
CH3COOH
E
CH3CHO
18
4 / CHEM 13 NEWS EXAM © 2004 UNIVERSITY OF WATERLOO
The decomposition of CH3CHO to CH4 and CO
is a first-order reaction. At a certain
temperature, the half-life of CH3CHO is found to
be 29 minutes. If the initial concentration of
CH3CHO is 1.0 mol L−1, then what is [CH3CHO]
after 87 minutes?
A
0.33 mol L−1
B
0.17 mol L−1
C
0.67 mol L−1
D
0.13 mol L−1
E
0.25 mol L−1
19
The reversible process shown below is an
elementary process which contributes to the
depletion of atmospheric ozone.
22
k1

→ NO2 + O2
O3 + NO ←

k −1
k1 and k−1 are the rate constants for the forward
and reverse reactions. Which of the following
conditions is satisfied when the process reaches
a state of dynamic equilibrium?
20
A
k1 = k−1
B
k−1 = (k1)−1
C
k1 + k−1 = 0
D
k1 =
E
k1 [O3] [NO] = k−1 [NO2] [O2]
23
[O3 ] [NO]
[NO2 ] [O2 ]
six
B
twelve
C
fifteen
D
eighteen
E
thirty-six
N3−
B
O2−
C
−
F
B
C20H23N
C
C87H8N5
D
C3H3N
E
C14H14N
Atomic masses are
given on the front page.
In an experiment, 17.2 mL of 0.0112 mol L−1
Ca(OH)2(aq) was required to neutralize all of the
H3PO4 in a 10.0-mL sample of H3PO4(aq). The
neutralization reaction is shown below.
What was the concentration of H3PO4 in the
sample that was analyzed?
Which one of the following ions has the smallest
ionic radius?
A
C7H8N3
→ Ca3(PO4)2(s) + 6 H2O(l )
24
21
A
3 Ca(OH)2(aq) + 2 H3PO4(aq)
For a xenon atom, Xe, in its ground electronic
state, how many electrons have n = 3?
A
Maprotiline is a prescription drug with the
following mass composition: 86.59% C, 8.36% H
and 5.05% N. What is the empirical formula of
the maprotiline?
A
0.0128 mol L−1
B
0.0193 mol L−1
C
0.0289 mol L−1
D
0.0963 mol L−1
E
0.0578 mol L−1
Methanoic acid, HCHO2, is an organic acid. What
is the pH of 0.015 mol L−1 HCHO2(aq) at 25oC?
A
1.82
B
2.80
C
3.72
D
5.55
E
6.82
Ka = 1.9×10−4 for HCHO2
Kw = 1.0×10 14
+
D
Na
E
Mg2+
© 2004 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 5
25
What is the equilibrium constant expression for the
reaction below?
28
Consider the titration curve below.
−
3 Sn(s) + 4 H+(aq) + 4 NO3 (aq) + H2O(l)
U
A
B
26
11
3 H2SnO3(s) + 4 NO(g)
10
9
[H2 SnO3 ] [NO]
Kc =
[Sn] [H+ ] [NO3− ]
=
Kc
=
6
4
3
D
[Sn]3 [H+ ]4 [NO3− ]4
Kc =
[H2 SnO3 ]3 [NO]4
=
5
4
[NO]
+ 4
[H ] [NO3− ]4
Kc
Kc
8
pH 7
[H2 SnO3 ]3 [NO]4
[Sn]3 [H+ ]4 [NO3− ]4
C
E
12
+
2
1
0
0
−
B
OH
C
NH3
D
NH4
E
HCl
-
Kb = 1.8×10 5 for NH3
Kw = 1.0×10 14
Sr(OH)2 at 25oC?
-
B
11.95
C
12.25
D
12.63
E
12.94
30
35
40
45
50
alizarin yellow, which is yellow for pH > 10.0
and red for pH < 12.0
B
thymolphthalein, which is colourless for
pH > 9.3 and blue for pH < 10.5
C
bromcresol purple, which is yellow for
pH < 5.2 and purple for pH > 6.8
D
thymol blue B, which is yellow for pH < 8.0
and blue for pH > 9.6
E
thymol blue A, which is red for pH < 1.2
and yellow for pH > 2.8
At a particular temperature, the equilibrium
constant for the reaction below is Kc = 4.0.
CO2(g) + NO(g) U CO(g) + NO2(g)
What is the pH of a saturated aqueous solution of
10.51
25
A
+
A
20
Which one of the following indicators is best for
detecting the equivalence point?
29
27
15
V (in mL)
[Sn] [H ] [
]
[H2 SnO3 ] [NO]
H3O+
10
−
NO3
Which of the following species has the highest
concentration at the equivalence point when
0.10 mol L−1 NH3(aq) is titrated by
0.20 mol L−1 HCl(aq)?
A
5
Ksp = 3.2×10 4 for Sr(OH)2
Kw = 1.0×10 14
6 / CHEM 13 NEWS EXAM © 2004 UNIVERSITY OF WATERLOO
If 4.0 mol CO2 and 4.0 mol NO are placed in a
1.0-L reaction vessel, what is the equilibrium
concentration of CO?
A
1.4 mol L−1
B
2.7 mol L−1
C
3.2 mol L−1
D
4.0 mol L−1
E
0.38 mol L−1
30
The following reaction reaches equilibrium in a
closed reaction vessel.
33
N2(g) + 3 H2(g) U 2 NH3(g)
The reaction is exothermic in the forward
direction. Which of the following increases the
mass of NH3 in the equilibrium mixture?
i.
ii.
adding a catalyst
decreasing the volume of the
reaction vessel
iii. increasing the temperature
31
32
34
A
i only
B
ii only
C
iii only
D
i and ii only
E
ii and iii only
What is the molecular geometry of SF4? (S is the
central atom.)
A
see-saw
B
trigonal pyramidal
C
T-shaped
D
tetrahedral
E
square planar
35
For sulfuric acid, H2SO4, the ionization constants
are Ka1 = 1×102 and Ka2 = 1×10−2 for the loss of
the first and second protons, respectively. What
is the correct relationship for a solution prepared
by dissolving 0.10 mol H2SO4 in water to make
1.0 L of solution?
A
[H+ ] < [SO24− ] < [HSO −4 ]
B
[H+ ] < [HSO 4− ] < [SO24− ]
C
[SO24− ] < [HSO −4 ] < [H+ ]
D
E
[
2−
SO 4
−
HSO 4
] < [H ] < [
−
HSO 4
[
+
]<[
2−
SO 4
+
]
] < [H ]
36
What is the formula of magnesium nitride?
A
MgN
B
Mg3N
C
MgN3
D
Mg2N3
E
Mg3N2
For PbI2, Ksp = 3.2×10−8. What is the molar
solubility of PbI2 in water?
A
1.6×10−5 mol L−1
B
2.0×10−3 mol L−1
C
1.6×10−4 mol L−1
D
4.0×10−4 mol L−1
E
3.2×10−8 mol L−1
Relative to the elements of the halogen group,
the metals of group 2
A
are better reducing agents
B
are more easily reduced
C
react readily with reducing agents
D
have larger first ionization energies
E
have larger electron affinities
Which of the following substances is the strongest
oxidizing agent in its standard state?
Ag+(aq) + e− → Ag(s) Eo = +0.799 V
Eo = +0.535 V
I2(s) + 2e− → 2I−(aq)
3+
−
Cr (aq) + 3e → Cr(s) Eo = −0.740 V
A
I−(aq)
B
Cr3+(aq)
C
I2(s)
D
Ag(s)
E
Cr(s)
© 2004 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 7
37
38
Which one of the following molecules has a nonzero dipole moment?
A
CCl4
B
BF3
C
CS2
D
PF3
E
SF6
−
→ x Cl−(aq) + y ClO3 (aq) + z H2O(l ).
What is the ratio x:y when the equation is
balanced?
H3SO4+
+
ClO4−
A
H2SO4 is the conjugate base of H3SO4+.
B
ClO4− is the conjugate acid of HClO4.
C
H2SO4 is the conjugate base of HClO4.
D
H2SO4 and HClO4 are both acids.
E
H3SO4+ is the conjugate base of H2SO4.
What is Eo for the reaction below?
3 Ni2+(aq) + 2 Cr(s) → 3 Ni(s) + 2 Cr3+(aq)
Ni2+(aq) + 2e- → Ni(s)
E o = -0.27 V
Cr3+(aq) + 3e- → Cr(s)
E o = -0.74 V
A
1.01 V
B
0.47 V
C
0.67 V
D
−0.67 V
E
−1.01 V
Chlorine, Cl2, disproportionates in aqueous basic
solution to give chloride and chlorate ions. The
unbalanced chemical equation is
a Cl2(g) + b OH −(aq)
Which statement is true for the following reaction?
H2SO4 + HClO4 →
39
40
8 / CHEM 13 NEWS EXAM © 2004 UNIVERSITY OF WATERLOO
A
1:1
B
3:1
C
1:3
D
5:1
E
1:5