Memorial University of Newfoundland
Chemistry 1050
FINAL EXAMINATION
FALL 2001
NAME:_____________________________
TIME: 2½ hours
STUDENT NUMBER:_______________
PROFESSOR:_______________________
READ THE FOLLOWING CAREFULLY.
1.
This examination has 10 pages consisting of two sections.
SECTION A is short-answer, SECTION B is long-answer questions. Ensure
that this examination paper is complete, i.e. that all pages are present.
2.
Failure to submit this paper in its entirety at the end of the examination will
normally result in disqualification.
3.
A Periodic Table and physical constants are provided. These are on the last
sheet of the paper and may be detached for use during the examination.
4.
Answer each question in the space provided.
Should you require more
space, use the back of the previous page and indicate clearly where this has
been done.
5.
Show all relevant calculations and justify all simplifying assumptions.
6.
Numerical answers should be reported to the appropriate number of
significant digits with the correct units (if any).
Do not write in the enclosed area below.
QUESTION
VALUE
MARK
Part A
A 1-12
22
Part B
B1 - B2
9
B3 - B5
15
B6 - B8
12
B9 - B11
16
B12 - B14
13
B15
13
TOTAL
100
Page 1 of 11 printed pages
Chemistry 1050
Section A
Short Answer Questions
(22 Marks)
[MARKS]
[2]
1.
The total pressure of a mixture of gases containing 6.80 g CO2 and 11.45 g
argon is 792 mmHg. Calculate the partial presure of the CO2 in the mixture.
[3]
2.
Complete the following table:
species
ground state electron configuration
Br –
P
V3+
[2]
3.
Complete the following table with the correct IUPAC name or formula:
Formula
IUPAC Name
Li2SO4·3 H2O
SF6
copper(I) oxide
silver chromate
[1]
4.
Use Kinetic-Molecular Theory to explain how a gas exerts pressure.
[1]
5.
Arrange the following bonds in order of increasing bond polarity:
C-F, C-N, Li-F, C-O, F-F
least polar: ____ < ____ < ____ < ____ < ____ :most polar
[1]
6.
Arrange the following solutions in order of increasing boiling point:
0.3 m NaCl(aq), 0.1 m CaCl2(aq), 0.5 m C6H12O6(aq), 0.1 m Al(NO3)3(aq)
lowest: ____ < ____ < ____ < ____ < ____ :highest
[2]
7.
Explain in terms of quantum numbers why the 2d subshell does not exist.
Page 2 of 11 printed pages
Chemistry 1050
[3]
8.
(a)
the enthalpy of combustion of C4H10(g).
(b)
the enthalpy of sublimation of iodine.
(c)
the third ionization energy of aluminum.
[2]
9.
Calculate the osmotic pressure of a solution containing 1.10 g of urea
(NH2)2CO in 100.0 mL of solution at 20.0 ºC.
[1]
10. Indicate the type of intermolecular forces largely responsible for
(a)
the high melting point of diamond (3500 ºC).
answer: ____________________
(b)
the high solubility of NaCl(s) is water.
answer: ____________________
[2]
11. Chlorophyll absorbs light at an energy of 3.056 x 10–19 J / photon. Calculate
the frequency and wavelength (in nanometers) of such photons.
[2]
12. A sample of neon gas with a partial pressure of 95.6 kPa in a 1.00 L
container at 25.0 ºC is cooled to –95.0 ºC at constant volume. Calculate the
new pressure of the neon gas.
Page 3 of 11 printed pages
Chemistry 1050
Section B
Long Answer Questions
(78 marks)
[MARKS]
[6]
1.
A 4.141 g sample of a gaseous compound occupies 428 mL at 60.0 ºC and
742 mmHg pressure. The compound consists of 17.73% carbon, 26.17%
chlorine and 56.10% fluorine by mass. Determine the molecular formula of
the gaseous compound.
[3]
2.
Determine the volume of 0.100 M HCl(aq) needed to react completely with
0.225 g Na2CO3(s).
Na2CO3(s) + 2 HCl(aq) → 2 NaCl(aq) + H2O(l) + CO2(g)
Page 4 of 11 printed pages
Chemistry 1050
[5]
3.
The element X forms the chloride XCl4 containing 54.4% chlorine by mass.
Determine the molar mass of X and identify it.
[6]
4.
Consider the following reaction for the conversion of NH3 to NO:
4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g)
In a certain experiment, 2.50 g NH3 reacted with 3.81 L of O2 measured at
STP. If the percentage yield of NO is 85.0%, calculate the volume of NO
produced, measured at 28.0 ºC and 102.8 kPa.
[4]
5.
Balance the equation for the following reaction occurring in acidic solution.
Include the balanced half reactions.
IO3–(aq) + HSO3–(aq) → I–(aq) + SO42–(aq)
Page 5 of 11 printed pages
Chemistry 1050
[4]
6.
Two solutions, 100.0 mL of 1.00 M HCl(aq) and 100.0 mL of 1.00 M
NaOH(aq), both initially at 21.1 ºC are mixed together in a coffee cup
calorimeter. The final temperature of the cup and its contents is 27.8 ºC.
Assume that the solution volumes are additive and that the resulting
NaCl(aq) has a density of 1.02 g/mL and a specific heat of 4.02 J g–1 ºC–1.
Calculate the enthalpy of neutralization per mole of H2O formed. State any
additional simplifying assumptions.
[5]
7.
Calculate the standard enthalpy change ∆Hº for the reduction of FeO by CO
as described by the equation:
FeO(s) + CO(g) → Fe(s) + CO2(g)
Data:
[3]
8.
Fe3O4(s) + CO(g) → 3 FeO(s) + CO2(g)
2 Fe3O4(s) + CO2(g) → 3 Fe2O3(s) + CO(g)
Fe2O3(s) + 3 CO(g) → 2 Fe(s) + 3 CO2(g)
∆Hº = +38 kJ
∆Hº = +59 kJ
∆Hº = –28 kJ
Calculate the amount of heat released when sufficient aluminum is used to
totally consume 25.0 kg of Fe3O4 in the thermite reaction given below:
3 Fe3O4(s) + 8 Al(s) → 4 Al2O3(s) + 9 Fe(s)
∆Hº = –3348 kJ
Page 6 of 11 printed pages
Chemistry 1050
[8]
9.
Complete the following table
CH2Cl2
SF4
Lewis structure
sketch of shape
name of shape
approximate bond angles
Indicate whether the
species is polar or
non-polar
Give the hybridization of
the central atom
[4]
[4]
10. (a)
Draw all plausible resonance structures for the nitrate ion, NO3–. Assign
formal charges to the atoms in each structure.
(b)
Determine the NO bond order in NO3–
(a)
The first ionization energy of oxygen is less than the first ionization
energy of nitrogen.
(b)
The radius of F– (1.33 8) is much larger than the radius of the F atom
(0.64 8).
answer: ________________
11.
Page 7 of 11 printed pages
Chemistry 1050
[4]
12. Use Valence Bond Theory to describe the bonding in the molecule C2H2.
Draw a diagram to illustrate the type of bonds formed, σ(sigma) and/or π(pi)
and the type of atomic orbitals used to form them.
[5]
13. (a)
σ2s
+
Complete the valence MO diagrams for NO+ and NO– given below.
Indicate whether either species is paramagnetic or diamagnetic. Give
the bond order of each species.
*
σ2s
σ2p
π2p
*
π 2p
*
σ2p
magnetic property
bond order
NO
-
NO
(b)
Which species would be expected to have the longer bond length, NO+
or NO–. Briefly explain.
14. When another atom or group of atoms is substituted for one of the hydrogen
atoms in benzene, C6H6, the boiling point changes. Briefly explain, in terms
of the relevant intermolecular forces, why the second molecule of each of the
following pairs has the higher boiling point.
[2]
(a)
C6H6 boils at 80 ºC while C6H5Cl boils at 132 ºC.
[2]
(b)
C6H5Br boils at 156 ºC while C6H5OH boils at 182 ºC.
Page 8 of 11 printed pages
Chemistry 1050
[4]
15. (a)
A solution containing 0.64 g of the hormone adrenaline in 36.0 g of CCl4
causes an elevation in the boiling point of 0.49 ºC. Calculate the molar
mass of adrenaline. Kb CCl4 = 5.02 ºC m–1.
[4]
(b)
The vapor pressure of chloroform CHCl3 is 40.0 mmHg at –7.1 ºC. It’s
enthalpy of vaporization is 29.2 kJ mol–1. Calculate its normal boiling
point.
[5]
(c)
An aqueous solution of nitric acid containing 5.13 M HNO3(aq) has a
density of 1.18 g/mL at 20 ºC. Calculate the mole fraction of the HNO3
in this solution.
Page 9 of 11 printed pages
Chemistry 1050
PERIODIC TABLE OF THE ELEMENTS
6
atomic mass
1
2
C
atomic number
H
He
12.011
1.0079
s-block
1
3
2
4
Li
Be
6.941 9.0122
11
12
Na
Mg
d-block
Ca
13
5
14
6
15
7
16
8
17
9
18
10
B
C
N
O
F
Ne
10.811 12.011 14.006 15.9994 18.998 20.179
3
4
5
21
22
23
24
25
26
27
28
29
30
Sc
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
22.989 24.305
19
20
K
4.0026
p-block
6
7
8
9
10
11
12
13
14
15
16
17
18
Al
Si
P
S
Cl
Ar
26.981 28.085 30.973 32.066 35.452 39.948
31
32
33
34
35
36
Ga
Ge
As
Se
Br
Kr
39.098 40.078 44.955 47.88 50.941 51.996 54.938 55.847 58.933 58.69 63.546 65.39 69.723 72.61 74.921 78.96 79.904 83.80
37
38
39
40
41
43
44
45
46
47
48
49
52
53
54
42
50
51
Rb
Sr
Y
Zr
Nb
Mo
Tc
85.467 87.62 88.905 91.224 92.906 95.94
55
56
57
72
73
74
Cs
Ba
La
Hf
Ta
W
Ru
(99)
75
Rh
Pd
Ag
Cd
In
Sn
Sb
Te
Bi
Po
Re
Os
Ir
Pt
Au
Hg
Tl
Pb
132.90 137.32 139.90 178.49 180.94 183.85 186.20 190.2 192.22 195.08 196.96 200.59 204.38 207.2 208.98 (210)
87
88
89
104
105
106
107
108
109
Fr
Ra
Ac
(223)
(226)
(227)
I
At
Rn
(210)
(222)
f-block
Lanthanides
58
59
60
61
62
63
64
65
66
67
68
69
70
71
Ce
Pr
Nd
Pm
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu
140.11 140.90 144.24 (147) 150.36 151.96 157.25 158.92 162.50 164.93 167.26 168.93 173.04 174.96
Actinides
Xe
101.07 102.90 106.42 107.86 112.41 114.82 118.71 121.75 127.60 126.90 131.29
76
77
78
79
80
81
82
83
84
85
86
90
91
92
93
94
95
96
97
98
99
100
101
102
103
Th
Pa
U
Np
Pu
Am
Cm
Bk
Cf
Es
Fm
Md
No
Lw
(253)
(256)
(253)
(257)
231.03 (231) 238.02 (237)
(242) (243) (247) (247) (249) (254)
Parenthesis Indicates the most stable isotope
SOME USEFUL CONSTANTS
Quantity and Symbol Value
Avogadro Constant, N 6.022 x 1023 particles·mol-1
Density of H2O(l) (near 0°C) 1.00 g·mL-1
Standard Temperature and Pressure (STP) 273.15 K = 0°C
101.325 kPa = 1 atm = 760 mmHg = 760 torr
Molar Volume of an Ideal Gas at STP 22.4 L·mol-1
Ideal Gas Constant, R 8.314 L·kPa·mol-1·K-1
8.314 J·mol-1·K-1
8.21 x 10-2 L·atm·mol-1·K-1
Specific Heat of H2O(l) near room temperature 4.184 J·g-1·K-1
∆Hfusion, H2O(s) at 273 K 6.02 kJ·mol-1
∆Hvaporization, H2O(l) at 373 K 41.1 kJ·mol-1
Planck Constant, h 6.626 x 10-34 J·s
Velocity of Light in a vacuum, c 2.998 x 108 m·s-1
Ionization Constant of Water, Kw, at 25°C 1.008 x 10-14
Faraday Constant, F 9.6485 x 104 C·mol-1
CONVERSION FACTORS
1 atm = 101.3 kPa = 760 mmHg (torr)
1 atomic mass unit, u = 1.660 x 10-27 kg
1 cal = 4.184 J
1 L = 1 dm3
You may detach this page if you wish. It must be handed in with the examination paper!
Printed November 28, 2001
Page 10 of 11 printed pages
Chemistry 1050
Do not turn the paper over until you are told that you may do so.
You may not leave the examination room during the first half hour or during the last half
hour of the examination.
At the end of the examination:
ACADEMIC OFFENCES
Academic offences shall be deemed to include, but shall not be limited to, the following:
1.
2.
3.
Cheating
on
examinations,
theses,
assignments, work term reports, projects,
internship reports, or any other tests.
Cheating includes copying from another student’s
work or allowing another student to copy from
one’s own work, consulting with any unauthorized
person during an examination or test, or using
unauthorized aids; or knowingly recording or
reporting false empirical or statistical data. The
work referred to includes examinations, theses,
assignments, work term reports, projects,
internship reports, or any other tests which are to
be used in judging the student’s performance in a
course or programme of study, or on any special
tests which the University may offer.
Impersonating another student or allowing
oneself to be impersonated.
By impersonation is meant the imitation of a
student or entrance into an arrangement with
another person to be impersonated for purposes
of taking examinations or tests or carrying out
laboratory or other assignments.
Plagiarism.
Plagiarism is the act of presenting the ideas or
works of another as one’s own. This applies to all
material such as essays, laboratory reports, work
term
reports,
design
projects,
seminar
presentations,
statistical
data,
computer
programmes and research results. The properly
NOTE:
4.
5.
6.
7.
acknowledged use of sources is an accepted and
important part of scholarship.
Use of such
material without acknowledgement, however, is
contrary to accepted norms of academic
behaviour.
Theft of examination papers or other material.
By theft is meant obtaining by any improper
means examination papers, tests, or any other
such material.
Use and/or distribution of stolen material.
The use of material which the student knows to
have been improperly obtained and/or the
distribution of such material is considered to be
an academic offence.
Submitting false information.
This offence includes falsifying academic forms or
records, submitting false credentials, medical or
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Submitting work for one course which has
been or is being submitted for another course
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This includes the presentation of an essay, report
or assignment to satisfy some or all of the
requirements of a course when that essay, report,
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is concurrently being submitted for another
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professor(s) involved.
Procedures to be followed and penalties to be assessed in cases of
academic dishonesty are outlined in the University Calendar.