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CH1S001
UNIVERSITY OF DUBLIN
TRINITY COLLEGE
FACULTY OF SCIENCE
Department of Chemistry
Junior Freshman
Hilary Term, 2004
Multiple Choice Test 1
Monday 12th January
12.00 – 13.00
Exam Hall and Goldsmith Hall
Answer All questions
A Periodic Table giving Atomic Weights etc., and a Table of fundamental constants is
attached.
INSTRUCTIONS
1.
Using a soft pencil (grade B or softer) complete sections A, B, C and D on the
Computer Answer Form. Write your student number in Section D as well as
marking the number on the form by filling in the box with a clear thick horizontal
line (not a , X or 0).
GOOD
BAD
BAD
BAD
BAD
2.
Answer each question by first marking on the question paper the answer that you
think is appropriate. Do not mark more than one answer to each question. In
questions with numerical answers, mark the answer closest to yours, if you do not
get exactly any of those given.
3.
Carefully transfer your answers to the Computer Answer Form. If you make a
mistake, rub it out with a CLEAN eraser and enter the correct answer. Use only a
soft pencil and mark your answers with a clear thick horizontal line. Failure to do
this could result in the misreading of your form. Do not write comments on the
form.
4.
When you have finished, make sure your name, student number and seat number
are on the Computer Answer Form and hand it up to the invigilator. Do not in any
way tear, crumple or deface the form. This form is the only record of your answers.
5.
There will be no negative marking for this exam.
1.
Which of the following statements is incorrect ?
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(a)
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The mass number is equal to the sum of the number of protons and
neutrons in an atom.
(b)
Isotopes of the same element have the same atomic number but different
mass numbers.
(c)
The elements in the Periodic Table are listed in order of increasing
atomic number.
(d)
The molar mass is the mass in grams of one mole of a substance.
(e)
Elements in the same Group of the Periodic Table have the same
electronic configuration.
Correct answer (e)
2.
Lactic acid (C3H6O3) is responsible for the sour taste in out-of-date milk.
57.04 mL of 0.098 M NaOH is required to neturalise 50.0 mL of a lactic acid
solution.
C3H6O3
+ NaOH
 H2O
+
C3H5O3Na
What is the molarity of the lactic acid solution?
(a)
0.098 M
(b)
0.112 M
(c)
0.224 M
(d)
0.056 M
(e)
1.000 M
Correct answer (b)
3.
Balance the equation below for the reaction of acid with a solution of MnO42.
How many moles of MnO42 are used to form 1 mole of MnO2 in the balanced
equation?
MnO42
+ H+
(a)
one mole
(b)
two moles
(c)
three moles
(d)
four moles
(e)
five moles.
Correct answer (c)

MnO4
+ MnO2
+ H2O
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4.
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Which of the following statements are correct ?
(i)
The oxidation number of Mn in MnO4 is V
(ii)
Lithium has an atomic number of three
(iii)
The molar mass of Ca3(PO4)2 is 100 gmol1
(iv)
The reaction of BaCl2 with Na2SO4 is an example of a precipitation
reaction
(v)
The mass percentage of carbon in CaCO3 is 12%
(a)
i, ii and iii only
(b)
i and ii only
(c)
ii and v only
(d)
ii, iv and v only
(e)
iii, iv and v only
Correct answer (d)
5.
For ideal gases which of the following statements are incorrect?
i.
At constant temperature, the volume of a fixed mass of gas is inversely
proportional to its pressure.
ii.
At constant temperature and pressure the volume of 1 mole of any gas is
always 22.4L
iii.
Equal masses of any gas have the same number of molecules
iv.
At constant pressure and temperature, 1L of O2 reacts with 2L of CO to
form 2L of CO2.
(a)
(ii) and (iii) only
(b)
(i), (ii) and (iv) only
(c)
(i) and (iii) only
(d)
(iii) and (iv) only
(e)
(ii) only.
Correct answer (a)
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6.
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Given the following thermochemical data:
Hof (NO) = +90.0 kJ mol-1; 2CO(g) + O2 (g)  2CO2(g) Horxn = -560.0 kJ
Calculate the standard enthalpy change for: CO(g) + NO (g)  CO2(g) + ½ N2(g)
(a)
–325 kJ
(b)
–370 kJ
(c)
–450 kJ
(d)
–505 kJ
(e)
–550 kJ
Correct answer (b)
7.
H for the transformation
grey tin
white tin
is 2.09 kJ mol-1 and S is 7.31 J mol-1 K-1. What temperature range favours the
formation of grey tin.
(a)
Above 286 K
(b)
Below 286 K
(c)
Above 572 K
(d)
Below 572 K
(e)
Above 304 K
Correct answer (b)
8.
Consider a process during which water freezes in a cold container to form ice.
Which of the following statements correctly describes the changes that occur
during this process ?
(a)
The free-energy of the system decreases, the entropy of the system
increases and the enthalpy of the system increases.
(b)
The free-energy of the system decreases, the entropy of the system
increases and the enthalpy of the system decreases.
(c)
The free-energy of the system decreases, the entropy of the system
decreases and the enthalpy of the system decreases.
(d)
The free-energy of the system increases, the entropy of the system
increases and the enthalpy of the system increases.
(e)
The free-energy of the system increases, the entropy of the system
decreases and the enthalpy of the system decreases.
Correct answer (c)
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9.
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A C60 ‘buckyball’ weighing 1.1956  1021 grams travels at one tenth the
velocity of light. What is its de Broglie wavelength?
(a)
1.848  1017 m
(b)
1.848  1012 m
(c)
1.848  10+1 m
(d)
1.848  10+10 m
(e)
1.848  10+20 m
Correct answer (a)
10.
The electron in a hydrogen atom falls from the 4th to the 2nd shell. The emitted
light has:
(a)
a wavelength 4.862  1010 m
(b)
a wavelength 9.843  109 m
(c)
a frequency 6.1661 1018 Hz
(d)
an energy 4.0856  1021 J
(e)
an energy 246.06 kJ mol1
Correct answer (e)
11.
The Ni2+ ion:
(a)
has four unpaired electrons
(b)
has five unpaired electrons
(c)
has eight electrons in its outer shell
(d)
has electron spin ½
(e)
is non-magnetic.
Correct answer (c)
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12.
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The ionization energy of the oxygen atom is less than that of the nitrogen atom
because:
(a)
the 2p orbital has higher energy than the 2s
(b)
there is greater repulsion in the 2p subshell of O than in the 2p of N
(c)
Hund’s Rule requires maximum electron spin in the N atom
(d)
O has greater nuclear charge than N
(e)
The O atom has a smaller ionic radius than the N atom.
Correct answer (b)
13.
Molecular orbital theory predicts that the F22+ ion:
(a)
has a bond order of 3
(b)
has zero binding energy
(c)
has unpaired electrons
(d)
has an empty bonding  molecular orbital
(e)
is non-magnetic.
Correct answer (c)
14.
The complete combustion of 2.1 g of propene gives:
(a)
13.20 g of CO2 and 5.40 g of H2O
(b)
7.33 g of CO2 and 4.50 g of H2O
(c)
5.81 g of CO2 and 3.56 g of H2O
(d)
6.60 g of CO2 and 2.70 g of H2O
(e)
6.60 g of CO2 and 5.40 g of H2O
Correct answer (d)
15.
Cyclohexane can exist:
(a)
as a chair conformer only
(b)
as both boat and chair conformers
(c)
as a chair conformer where all the C-H bonds are equatorial
(d)
as a boat conformer only
(e)
as a chair conformer where all the C-H bonds are axial.
Correct answer (b)
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16.
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The reaction that takes place between bromine and (E)-but-2-ene is:
(a)
a free radical addition reaction
(b)
an acid-catalysed addition reaction
(c)
an endothermic addition reaction
(d)
an electrophilic addition reaction
(e)
an impossible addition reaction.
Correct answer (d)
©University of Dublin 2004
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CH1S001
Department of Chemistry
Use the following values for fundamental constants, conversion factors, atomic masses
and other data for examination purposes:
Constants
Gas Constant
R = 8.314 J K1 mol1
(R = 8.206  10-2 L atm K-1 mol-1)
Boltzmann’s Constant
kB = 1.381  1023 J K1
Planck’s Constant
h = 6.626  1034 J s
 = h/2 = 1.055  1034 J s
Velocity of light
c = 2.998  108 m s-1
Charge of electron
e = 1.602  1019 C
Rest mass of electron
me = 9.109  1031 kg
Rest mass of proton
mp = 1.673  1027 kg
Vacuum permittivity
o = 8.854  1012 J1 C2 m1
Vacuum permeability
o = 4  107 J s2 C-2 m-1
Bohr magneton
 = 9.274  1024 J T-1
Nuclear magneton
n = 5.051  1027 J T-1
Rydberg constant
R= 2.178  1018 J = 1.097  105 cm-1
Avogadro’s constant
NA = 6.022  1023 mol-1
Faraday constant
F = NAe = 9.648  104 C mol1
Bohr radius
ao = 5.292  1011 m
Molar volume at S.T.P.
Mv = 22.414 dm3 mol1
Conversion factors etc.
1 eV = 1.602  1019 J = 9.648  104 J mol1
1 cm1 = 1.986  1023 J = 11.96 J mol1 = 1.240  104 eV
1 Å = 0.1 nm = 1010 m
1 standard atmosphere = 1.013  105 N m-2 (Pa) = 760 torr = 1013 mbar
1 L = 1 dm3 = 103 m3
1 Debye (D) = 3.336  1030 C m
1 calorie = 4.184 J
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The Periodic Table of the Elements
18
1
2
2
H
13
14
15
16
17
1.0079
3
4
5
Li
Be
6.941
9.01218
11
( ) mass numbers of most stable isotope
12
Na
Mg
22.98977
24.305
3d, 4d, 5d
20
6
21
4
22
5
23
6
24
7
25
8
26
9
27
10
28
11
29
8
9
10
B
C
N
O
F
Ne
12.011
14.0067
15.9994
18.9984
20.179
12
30
7
10.81
13
3
19
He
4.0026
14
15
16
17
18
Al
Si
P
S
Cl
Ar
26.9815
28.0855
30.9738
32.06
35.453
39.948
31
32
33
34
35
36
K
Ca
Sc
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
Ga
Ge
As
Se
Br
Kr
39.0983
40.08
44.9559
47.88
50.9415
51.996
54.938
55.847
58.9332
58.69
63.546
65.38
69.72
72.59
74.9216
78.96
79.904
83.80
37
28
29
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
Rb
Sr
Y
Zr
Nb
Mo
Tc
Ru
Rh
Pd
Ag
Cd
In
Sn
Sb
Te
I
Xe
85.4678
87.62
88.9059
91.22
92.9064
95.94
(97.9)
101.07
102.9055
106.42
107.868
112.41
114.82
118.69
121.75
127.60
126.9045
131.29
55
56
Cs
Ba
132.9054
137.33
87
88
57
72
#
73
74
75
76
77
78
79
80
81
82
83
84
85
86
La
Hf
Ta
W
Re
Os
Ir
Pt
Au
Hg
Tl
Pb
Bi
Po
At
Rn
138.9055
178.49
180.9479
183.85
186.207
190.2
192.22
195.08
196.9665
200.59
204.383
207.2
208.9804
(209)
(210)
(222)
89
Fr
Ra
*Ac
(223)
226.0254
227.0278
# LANTHANUM SERIES
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
140.12
140.9077
144.24
(145)
150.36
151.96
157.25
158.9254
162.50
164.9304
167.26
168.9342
173.04
174.967
* ACTINIUM SERIES
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
Lr
232.0381
231.0359
238.0389
237.0482
(244)
(243)
(247)
(247)
(242.1)
(254)
(257)
(258.1)
(259.1)
(260)