Download avogadro exam 2001 - University of Waterloo

AVOGADRO EXAM 2001
UNIVERSITY OF WATERLOO
DEPARTMENT OF CHEMISTRY
17 MAY 2001
TIME: 75 MINUTES
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Code 1
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Code 12 Teacher
H
He
Li
Be
B
C
N
O
F
Ne
Na
Mg
Al
Si
P
S
Cl
Ar
K
Ca
Sc
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
Ga
Ge
As
Se
Br
Kr
Rb
Sr
Y
Zr
Nb
Mo
Tc
Ru
Rh
Pd
Ag
Cd
In
Sn
Sb
Te
I
Xe
Cs
Ba
La*
Hf
Ta
W
Re
Os
Ir
Pt
Au
Hg
Tl
Pb
Bi
Po
At
Rn
Fr
Ra
Ac**
* Lanthanides
** Actinides
AVOGADRO EXAM 2001 - ANSWERS
1
How many mm3 are there in one m3 ?
A
B
C
2
4
10+6
Al3+
B
B3+
C
N3-
D
V3+
E
Ne3-
10+3
10-3
E
10-9
Two students made independent measurements of
the mass of an object using four different balances.
Their results are shown below.
Student A:
51.6 g, 50.8 g, 53.4 g, 49.3 g
Average value: 51.3 g
Student B:
50.1 g, 49.6 g, 51.0 g, 49.4 g
Average value: 50.0 g
5
The true mass is exactly 51 g. Which statement is
correct?
A
The results of Student A are more accurate but
less precise.
B
The results of Student A are more accurate and
more precise.
C
The results of Student B are more accurate and
more precise.
D
The results of Student B are more accurate and
less precise.
6
How many neutrons are there in one
A
37
B
17
C
18
D
20
E
54
37Cl
atom?
In what region of the periodic table are the atoms with
the smallest covalent atomic radii found?
A
upper left
B
lower left
C
upper right
D
lower right
E
upper centre
None of the above statements is true.
7
3
A
10+9
D
E
Which monatomic ion has an atomic number of 13
and 10 electrons?
The nucleus of any atom, except hydrogen, is made
up of
A
only neutrons.
B
only protons.
C
equal numbers of electrons and protons.
D
equal numbers of protons and neutrons.
E
neutrons and protons.
The first ionization energy of an isolated atom, X(g), is
A
the minimum energy required to remove an
electron from X(g).
B
the maximum energy required to remove an
electron from X(g).
C
the energy released when X acquires an electron
to form X-(g).
D
the minimum energy required to remove an
electron from X-(g)
E
the maximum energy required to remove an
electron from X-(g).
 2001 UNIVERSITY OF WATERLOO AVOGADRO EXAM /2
8
Which one of the following elements would you
expect to be the most similar in chemical properties to
oxygen?
12 A U-tube mercury manometer is open on the right
arm and connected to a gas sample at the other arm
as shown below. The atmospheric pressure is 101
kPa and the difference in levels of mercury is 20 cm.
What is the pressure of the gas in the bulb?
A
carbon
B
nitrogen
A
121 kPa
C
fluorine
B
104 kPa
D
neon
C
94 kPa
E
sulfur
D
98 kPa
E
128 kPa
760 mm Hg = 101 kPa
gas
20 cm
9
Which of the following is not a mixture?
A
brass
B
sodium chloride
C
air
D
seawater
E
stainless steel
13 A 140-g sample of nitrogen gas in a rigid container
exerts a pressure of 203 kPa at 127oC. What is the
volume of the container?
10 Noble gases are usually unreactive but a few
compounds of the noble gases have been
synthesized. Which one of the following chemical
bonds is least likely to form?
A
82 L
B
26 L
R = 8.3145 kPa L K-1 mol-1
C
110 L
N, 14.01 g mol-1
D
160 L
0oC = 273.15 K
E
52 L
A
Xe-O
B
Xe-F
C
Xe-N
D
Kr-F
A
16 g mol 1
E
Ar-F
B
19 g mol 1
C
40 g mol 1
D
80 g mol
E
none of the above
14 A 7.20-L flask contains 20.0 g of an unknown gas at a
pressure of 104 kPa and a temperature of 87oC.
What is the molar mass of the gas?
11 Which compound contains both covalent and ionic
bonds?
A
HClO4
B
CsCl
C
graphite
D
KCN
E
water
Note: Some teachers commented that
HClO4 has ionic and covalent bonds. To the
best of our knowledge, pure HClO4 is a
liquid comprised of molecules with no ionic
bonds. The monohydrate, HClO4$H2O,
+
however, is an ionic solid comprised of H3O
−
and ClO4 ions.
-
-1
 2001 UNIVERSITY OF WATERLOO AVOGADRO EXAM /3
15 What is the total pressure in a 4.55-L container if it
contains 0.0410 mol O2, 0.173 mol N2 and 0.056 mol
He, at a temperature of 167oC?
19 Which of the following has the lowest melting point?
A
CaO(s)
B
Si(s)
C
C6H12O6(s)
A
250 kPa
B
82.4 kPa
C
217 kPa
D
NaNO3(s)
D
0.0232 kPa
E
SiO2(s)
E
2.14 kPa
R = 8.3145 kPa L K-1 mol-1
0oC = 273.15 K
16 Which of the following gaseous compounds behaves
most like an ideal gas at 298 K and 101 kPa?
20 What is the maximum mass of iron that can be
recovered from 1.06 L of 0.20 M Fe2(SO4)3 solution?
A
12 g
Fe, 55.85
B
24 g
S, 32.07
A
NO
B
H2S
C
6.0 g
C
HF
D
80 g
D
N2
E
40 g
E
SO3
17 What is the correct formula of the stable compound
that contains only aluminum and sulfate ions?
A
B
21 A compound of sulfur and phosphorus contains
72.13% sulfur by mass. What is the empirical formula
of this compound?
A
P2S5
B
P2S3
C
PS3
D
P2S
E
PS2
Al2S3
AlSO4
C
Al3S2
D
Al3(SO4)2
E
Al2(SO4)3
18 Which of the following molecules is not planar? (The
central atom is underlined and all other atoms are
bonded to it.)
O, 16.00
S, 32.07
P, 30.97
22 Magnesium burns in oxygen to produce magnesium
oxide, MgO. If 5.0 moles of magnesium and 4.0
moles of oxygen react to produce as much MgO as
possible, how much of the excess reactant remains?
A
SF4
A
1.0 mol Mg
B
BrF3
B
1.0 mol O2
C
SO3
C
1.5 mol O2
D
H2CO
D
3.0 mol Mg
E
AlF3
E
0.5 mol Mg
 2001 UNIVERSITY OF WATERLOO AVOGADRO EXAM /4
23 What volume of 12 M HCl(aq) solution is required for
the preparation of 7.50 L of 0.10 M HCl(aq)?
A
6.3 L
B
63 mL
C
0.16 L
D
0.90 L
E
9.0 mL
26 Gastric fluid in the human stomach has a pH of 1.2.
What is [H+] in gastric fluid?
A
1.2 mol L-1
B
0.12 mol L-1
C
12 mol L-1
D
15.8 mol L-1
E
0.063 mol L-1
24 Consider the unbalanced equation
KMnO4 + HCl → KCl + MnCl2 + Cl2 + H2O.
If the coefficient of KMnO4 in the balanced equation is
taken to be 2, what is the coefficient of HCl ?
A
8
B
16
C
4
D
2
E
5
27 Which of the following is the poorest conductor of
electricity?
A
1.0 M HCl(aq)
B
a saturated, aqueous solution of CCl4
C
molten sodium chloride
D
1.0 M NH3(aq)
E
solid platinum
28 Diamond and graphite are
25 What products result from adding solid calcium oxide
to water?
A
calcium hydroxide
B
calcium hydroxide and hydrogen gas
C
calcium hydride and oxygen gas
D
calcium hydride and calcium hydroxide
E
calcium metal, hydrogen gas, and oxygen gas
A
stereoisomers.
B
enantiomers.
C
allotropes.
D
isotopes.
E
structural isomers.
29 In which reaction does a precipitate form?
A
AgNO3(aq) + NH4NO3(aq) →
B
NH4Cl(aq) + NaOH(aq) →
C
CuSO4(aq) + HNO3(aq) →
D
HNO3(aq) + KOH(aq) →
E
Fe(NO3)2(aq) + Na2S(aq) →
 2001 UNIVERSITY OF WATERLOO AVOGADRO EXAM /5
30 What is the systematic, IUPAC name for Fe2O3 ?
A
B
34 What is the approximate bond angle in the H2O
molecule? (Choose the closest value.)
iron(III) oxide
A
60o
B
90o
C
109o
D
120o
E
180o
iron oxide
C
iron(II) oxide
D
iron (II) trioxide
E
iron trioxide
31 What is the oxidation number of chlorine in HClO2 ?
A
+5
B
+3
C
+7
D
-1
E
0
35 What is the net ionic equation for the reaction that
occurs when aqueous barium chloride reacts with
aqueous sulfuric acid?
32 In the reaction,
A
BaCl2(aq) + H2SO4(aq) → BaSO4(s) + 2HCl(aq)
B
H+(aq) + Cl-(aq) → HCl(g)
C
Ba2+(aq) + SO 4 (aq) → BaSO4(s)
D
Br2(l) + 2OH-(aq) → OBr-(aq) + Br-(aq) + H2O(l)
the reducing agent and the oxidizing agent are,
respectively
A
Br2 and OH-
B
Br2 and Br-
C
OH- and Br2
D
Br2 and Br2
E Br2 and OBr-
E
2-
2Ba2+(aq) + 2Cl-(aq) + 2H+(aq) + SO 4 (aq)
→ BaSO4(aq) + 2HCl(g)
2-
Ba2+(aq) + SO 4 (aq) → BaS(s) + 2O2(g)
36 The addition of HCl to C2H4 produces C2H5Cl. In a
certain experiment, 5.61 grams of C2H4 reacts with
excess HCl and 4.83 grams of C2H5Cl is recovered.
What is the percent yield for the experiment?
A
86.1%
B
37.4%
C, 12.01
C
20.0%
Cl, 35.45
D
16.1%
E
13.9%
H, 1.01
33 Which molecule has a triple bond?
A
C2H2
B
C2H4
C
O2
D
CO2
E
N2H2
 2001 UNIVERSITY OF WATERLOO AVOGADRO EXAM /6
40 A sample of water, initially at 25oC, was heated at a
constant rate of 1.00 kJ per second until the
temperature was 110oC. Which of the following
graphs of temperature versus time best depicts the
variation of temperature with time?
37 Which of the following is not endothermic?
A
CO2(s) → CO2(g)
B
Br2(l) → Br2(g)
C
O(g) + e- → O-(g)
D
H2(g) → 2H(g)
A
E LiF(s) → Li (g) + Cl-(g)
+
38 Which of the following represents the ground
electronic configuration of an isolated halogen atom?
2
1
A
1s 2s
B
1s 2s 2p
C
1s 2s 2p
D
1s 2s 2p 3s 3p 4s 3d
E
1s 2s 2p 3s 3p
B
2
2
4
2
2
6
2
2
6
2
6
2
2
6
2
5
2
5
C
39 What is [Na+] when 35.0 mL of 0.284 M Na2SO4(aq)
and 45.0 mL of 0.196 M NaNO3(aq) are mixed?
Assume the final volume is 80.0 mL.
A
0.234 mol L-1
B
0.172 mol L-1
C
0.248 mol L-1
D
0.359 mol L-1
E
0.382 mol L-1
D
E
 2001 UNIVERSITY OF WATERLOO AVOGADRO EXAM /7