Download CHEM 13 NEWS EXAM 1998 - University of Waterloo

CHEM 13 NEWS EXAM 1998
UNIVERSITY OF WATERLOO
DEPARTMENT OF CHEMISTRY
14 MAY 1998
TIME: 75 MINUTES
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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
1.
What is the correct order of increasing bond angle
between bonded H, C and C atoms?
A
alkenes
<
alkynes
<
alkanes
B
alkanes
<
alkynes
<
alkenes
C
alkanes
<
alkenes
<
alkynes
D
alkynes
<
alkanes
<
alkenes
E
alkynes
<
alkenes
<
alkanes
5. Which compound would not be expected to react
with metallic sodium?
A
CH3— O — CH3
B
CH3CH2OH
O
CH3
C
OH
C
2. Which functional group does not contain an oxygen
atom?
OH
A
an amide
B
an amine
D
C
an aldehyde
E
D
an alcohol
E
an ester
C2H5NH2
6. The reaction of an alcohol with a carboxylic acid in
organic chemistry resembles the reaction of an
inorganic hydroxide with an acid only in
3. 2-methylpropane differs from butane in that the
former
A
the speed of the reaction.
A
has a higher molecular weight.
B
the completeness of the reaction.
B
has a different percentage composition.
C
the production of an ionic salt as one end
product.
C
is not a saturated hydrocarbon.
D
the production of water as one end product.
D
has a different empirical formula.
E
the production of an ester as one end product.
E
has a different structural formula.
4. Which compound will react most rapidly with
7. Which of the following represents the ground state
bromine?
electron configuration of the Mn3+ ion?
(Atomic number of Mn is 25)
A
CH4
A
1s2 2s22p6 3s23p63d4
B
C6H6
B
1s2 2s22p6 3s23p63d5 4s2
C
C2H4
C
1s2 2s22p6 3s23p63d2 4s2
D
C2H6
D
1s2 2s22p6 3s23p63d6 4s2
E
C2H4Cl2
E
1s2 2s22p6 3s23p63d3 4s1
 1998 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM /2
8. The critical temperature of a substance is
11. Which one of the following species has a molecular
dipole moment of zero?
A
the temperature at which the vapour pressure of
the liquid is equal to the external pressure.
B
the temperature at which the vapour pressure of
the liquid is equal to 760 mm Hg.
C
the temperature at which the solid, liquid, and
vapour phases are all in equilibrium.
D
E
the temperature at which liquid and vapour
phases are in equilibrium at 1 atmosphere.
the lowest temperature above which a substance
cannot be liquefied at any applied pressure.
A
CO2
B
H2O
C
CH2Cl2
D
CCl4
E
NH3
12. In which of the following series are the diatomic
molecules arranged in order of increasing bond
length?
H3O+
9.
_
NH4+
CH4
NO3
CO32
H2O
N3
OCN
O3
CO2
PCl5
SF6
_
_
_
How many of the molecules and ions above have a
total of eight valence electrons?
A
2
B
4
C
6
D
7
E
8
A
F2, Cl2, ICl , BrCl , I2
B
F2, Cl2, BrCl , ICl , I2
C
F2, BrCl , Cl2, I2, ICl
D
F2, Cl2, BrCl , I2, ICl
E
F2, ICl , BrCl , Cl2, I2
13. When a sample of oxygen gas in a closed container
of constant volume is heated until its absolute
temperature is doubled, which of the following is also
doubled?
A
the density of the gas
B
the pressure of the gas
C
the average velocity of the gas molecules
melting point at standard pressure?
D
the number of molecules per cm3
A
aluminum
E
the potential energy of the molecules
B
silicon
C
phosphorus
D
sulfur
E
chlorine
10. Of the following elements, which has the highest
 1998 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM /3
14. The oxidation of iodide ions by arsenic acid in acidic
aqueous solution occurs according to the
stoichiometry shown below.
H3AsO4 + 3I- + 2H3O+ → H3AsO3 + I3- + 3H2O
3
4
3
B
Energy
The experimental rate law of the reaction is:
Rate = k [H AsO ] [I-] [H O+]
C
What is the order of the reaction with respect to I- ?
Substance X
A
1
B
2
C
3
D
5
E
6
A
Substance Y
0
Reaction Profile
16. From the energy profile diagram shown above,
choose the one correct statement:
15. When 10 mL of 1.00 mol/L HCl is mixed with 10 mL
of 1.00 mol/L NaOH, the temperature of the solution
rises by 8.5oC. Assuming no heat loss to the
container or surroundings, what is the heat of
reaction for
H+ (aq) + OH- (aq) → H2O (l) ?
(The heat capacity of water and dilute aqueous
solutions is about 4.2 J oC-1 g-1, and the density may
be taken as 1.00 g/mL.)
A
3.6 kJ/mol
B
7.1 kJ/mol
C
18 kJ/mol
A
Letter A represents the enthalpy change of the
reaction for X→Y and C is the activation energy
for X→Y.
B
Letter B represents the heat of reaction for X→Y
and A is the activation energy for X→Y.
C
Letter A represents the heat of reaction for X→Y
and C is the activation energy for Y→X.
D
Letter B represents the heat of reaction for X→Y
and C is the activation energy for Y→X.
E
Letter C represents the heat of reaction for Y→X
and B is the activation energy for Y→X.
Question was deleted.
17. In 30 days, 32P loses one-half of its radioactivity.
D
36 kJ/mol
E
71 kJ/mol
What percentage of the original radioactivity would
remain at the end of 15 days?
A
100%
B
87%
C
75%
D
71%
E
50%
 1998 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM /4
18. Complete and balance the equation for the
21. Given the following heats of reaction under standard
combustion of ZnS in excess oxygen,
conditions,
? ZnS + ? O2 → ? ZnO + ?
Use the smallest whole number coefficients (no
fractions). The number of moles and the formula of
the product containing S are
A
2S
B
S8
C(s) + O2(g) → CO2(g)
∆Ho = -394 kJ /(mol C)
H2(g) + ½ O2(g) → H2O(l)
∆Ho = -286 kJ /(mol H2)
CH4(g) + 2 O2(g) → CO2(g) + 2H2O(l)
∆Ho = -890 kJ /(mol CH4)
what heat of reaction is expected for the reaction,
C
SO2
D
2SO2
E
SO3
C(s) + 2H2 (g) → CH4 (g) ?
A
+1068 kJ/moloC
B
+782 kJ/moloC
C
-76 kJ/moloC
D
-1570 kJ/moloC
E
-1856 kJ/moloC
19. What is the ratio of the volume of hydrogen liberated
by the reaction of 0.2431 g magnesium with an
excess of 2.0 M hydrochloric acid and the volume of
hydrogen liberated by the reaction of the same
weight of magnesium with an excess of 1.5 M
sulphuric acid? (The molar mass of Mg is
24.31 g/mol)
A
1:4
B
1:2
C
1:1
D
2:3
E
4:3
22. Two flexible containers for gases are at the same
temperature and pressure. One holds 0.50 grams of
hydrogen and the other holds 8.0 grams of oxygen.
Which one of the following statements regarding
these gas samples is false? (The relative atomic
mass of oxygen is 16.0 and that of hydrogen
is 1.0)
20. Which one of the following statements is false ?
A
A system at chemical equilibrium has a constant
mass.
B
Reactant and product concentrations vary with
time in a system at chemical equilibrium.
C
Forward and reverse reactions proceed at the
same rate in a system at chemical equilibrium.
D
A system at chemical equilibrium opposes slight
disturbances.
E
A system at chemical equilibrium must have a
constant temperature.
A
The volume of the hydrogen container is the
same as the volume of the oxygen container.
B
The number of molecules in the hydrogen
container is the same as the number of
molecules in the oxygen container.
C
The density of the hydrogen sample is less than
that of the oxygen sample.
D
The average kinetic energy of the hydrogen
molecules is the same as the average kinetic
energy of the oxygen molecules.
E
The average speed of the hydrogen molecules is
the same as the average speed of the oxygen
molecules.
 1998 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM /5
26. How many moles of H3O+ are there in 1.8 L of pure
23. For this system at fixed pressure,
2SO3(g) ≡ 2SO2(g) + O2(g) ∆Ho = + 43 kJ/(mol SO3)
what is the effect of a small increase in temperature
on the rate to the right (rateright), rate to the left
(rateleft), and the equilibrium constant (Keq)?
rateright
Keq
-------------
rateleft
-----------
-------------
A
lower
higher
lower
B
higher
lower
unchanged
C
higher
higher
unchanged
D
higher
higher
higher
E
higher
higher
lower
water at 25oC?
Kw = 1.0 x 10-14 at 25oC
A
95 mol
B
32 mol
C
1.0 x 10-7 mol
D
1.8 x 10-7 mol
E
1.0 x 10-14 mol
27. Choose the correct statement about these two
reactions:
Cl- + H2O → HCl + OHCl- + PCl → PCl 3
A
Cl- does not act as a Lewis acid or base in
either of these reactions.
B
Cl- acts as a Lewis base in both of these
reactions.
C
Cl- acts as a Lewis base only in the second
reaction.
D
Cl- acts as a Lewis acid only in the first reaction.
E
Cl- acts as a Lewis acid in both of these
reactions.
24. If a salt is dissolved in water under conditions that
the solution becomes supersaturated, then the
solution
A
must contain some undissolved solute.
B
is not truly at equilibrium.
C
must be hot.
D
has an ion product less than the solubility
product constant of the salt.
E
must be above room temperature.
28. Which compound is the strongest acid in aqueous
25. If the following equation is balanced using the
solution?
smallest whole number coefficients,
-
?MnO4- + ?H+ + ?HNO2 → ?Mn2+ + ?H2O + ?NO3
what number appears before the HNO2 molecule?
A
1
B
2
C
3
D
4
E
5
4
A
HOCN
B
HOCl
C
HOClO
D
HOClO2
E
HOClO3
 1998 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM /6
29. A chemist accidentally mixes white NaBr powder
with white CsBr powder. When 1.00 g of the mixture
is analyzed, it is found to contain 0.492 g Br. What
is the percentage, by mass, of NaBr in the mixture?
A
82.3% NaBr
B
51.8% NaBr
Relative Atomic Mass
Cs
132.91
Na
22.99
Br
79.90
32. When the same amount of sodium acetate is added
to a 0.1 M solution of each substance listed below,
the acetate ions will attract protons from the acid that
is present. From which substance will the acetate
ions attract the largest number of protons?
Acid
HSO4-
C
43.9% NaBr
D
29.1% NaBr
HNO2
E
18.4% NaBr
HC2H3O2
30. Silver chloride is precipitated by adding HCl to a
solution of a silver salt until the concentration of
chloride ions (Cl-) is 0.20 M. What is the
concentration of silver ions in the remaining
solution?
HCN
HSA
NaHSO4
B
HNO2
Solubility Product Constant, Ksp
C
HC2H3O2
1.56 × 10-10
D
HCN
E
NaHS
AgCl
2
Ka (Ionization
Constant of Acid)
1.2 × 10-2
4.0 × 10-4
C2H3OCNS2-
1.8 × 10-5
7.2 × 10-10
1.2 × 10-13
Conjugate Base
SO42NO -
A
1.3 × 10-5 M
B
2.8 × 10-5 M
C
7.8 × 10-10 M
D
1.6 × 10-10 M
Ni2+(aq) + 2 e- → Ni(s)
Eo = -0.25 V
E
0.20 M
Fe2+(aq) + 2 e- → Fe(s),
Eo = -0.44 V
33. Given,
Pb2+(aq) + 2 e- → Pb(s), Eo = -0.13 V
31. Aluminum cookware does not react appreciably with
which of the following reactions is(are) spontaneous
under standard conditions?
hot water because
(1) Fe(s) + Ni2+(aq) → Fe2+(aq) + Ni(s)
A
the reaction is exothermic.
(2) Ni(s) + Pb2+(aq) → Ni2+(aq) + Pb(s)
B
hydrolysis of aluminum salts occurs.
(3) Pb(s) + Fe2+(aq) → Pb2+(aq) + Fe(s)
C
the aluminum has an oxide coating.
D
E
aluminum is not active enough to displace
hydrogen.
the radius to charge ratio of aluminum atoms is
small.
A
(1), (2) and (3)
B
(1) and (2) only
C
(1) and (3) only
D
(2) and (3) only
E
(3) only
 1998 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM /7
37. Two electrolytic cells, one containing a silver nitrate
34. To protect a buried pipe line made of iron from
corrosion, a bar of magnesium is buried close to the
pipe and connected to the iron. What is the best
explanation for this protective action?
A
Mg forms a protective coating over the iron.
B
Mg gains electrons more readily than Fe,
keeping the Fe from oxidizing.
C
Fe loses electrons less readily than Mg, making
Mg the anode.
D
Mg is more active than iron and forces the iron
to act as an anode.
E
An electrolytic cell is set up, with H2 gas being
evolved at the surface of Mg.
35. Sulfur may act as either an oxidizing agent or as a
reducing agent. What is the best theoretical
explanation for this statement?
A
Sulfur forms sulfur dioxide as well as calcium
sulfide.
B
Sulfur is a nonmetal.
C
Sulfur forms both organic and inorganic
compounds.
D
E
With six electrons in its outer shell the sulfur
atom can either gain electrons from other
elements or share its electrons with other
elements.
Sulfur is soluble in carbon disulfide as well as in
alcohol.
solution and the other containing a copper(II) sulfate
solution, were connected so that the same current
passed through both cells. A current was passed
through both solutions until 53.95 g of silver had
been deposited. What mass, in grams, of copper
was deposited?
A
15.9
B
27
C
31.8
D
54
E
63.5
Atomic Molar Masses
Ag 107.9 g•mol-1
Cu 63.5 g•mol-1
38. Given the following standard reduction potentials,
Standard Reduction Potentials
Mg2+ + 2e- ≡ Mg
Al3+ + 3e- ≡ Al
Zn2+ + 2e- ≡ Zn
Fe2+ + 2e- ≡ Fe
Cu2+ + 2e- ≡ Cu
Ag+ + e- ≡ Ag
Eo
-2.37 V
-1.66 V
-0.76 V
-0.44 V
0.34 V
0.80 V
What combination of metals together with their
1 M salt solutions would give a voltaic cell with
the highest possible voltage?
A
Mg and Al
B
Zn and Cu
C
Mg and Ag
D
Mg and Fe
E
Al and Ag
36. Which of the following is the strongest oxidizing
agent?
A
F2
B
Cl2
C
Br2
D
I2
E
Cl-
 1998 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM /8
39. Which substance is the source of the gas that fills an
automobile’s air bag?
A
compressed N2(g)
B
NaHCO3(s)
C
compressed CO2(g)
D
Na2SO4(s)
E
NaN3(s)
40. The electrolysis of a 0.1 M solution of potassium
hydroxide in water produces
A
hydrogen at the anode and oxygen at the
cathode.
B
hydrogen at the cathode and oxygen at the
anode.
C
oxygen at the cathode and potassium at the
anode.
D
potassium at the cathode and oxygen at the
anode.
E
potassium at the anode and hydrogen at the
cathode.
 1998 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM /9