THE UNIVERSITY OF MANITOBA
October 24
PAPER NO:
20
xxx
MID-TERM
PAGE NO:
DEPARTMENT & COURSE NO:
EXAMINATION:
07
Chemistry CHEM 1300
University I Chemistry: Models
TIME:
1 of
2
EXAMINATION
11
HOURS
EXAMINER: CHEM 1300 Committee______
This CHEM 1300 October mid-term examination paper is an objective-type, machine-scored examination. All
questions in this paper are of equal value.
There are forty-four (44) questions on this examination paper.
GENERAL INSTRUCTIONS
Do not fold, staple, tear, or otherwise mutilate the answer sheet.
Indicate your answers with a bold mark from a soft lead (graphite) pencil. Do NOT use ink, marking pen, etc.
If you do any erasing, be sure that erasures are complete.
Each question has ONE correct answer only. DO NOT MARK MORE THAN ONE ANSWER PER QUESTION.
Marks will NOT be deducted for wrong answers.
Blank sheets are attached to this examination to be used for rough work.
Numerical answers are correct to within 5%.
VERY IMPORTANT
For accurate processing of the answer sheet for this examination, we must have on your answer sheet:
1. your correct student number, and
2. your name
Write your University of Manitoba 7-digit student number in the column marked by a coloured arrow on the answer
sheet and score your student number correctly in the area to the right of this column.
Submit the ANSWER SHEET for grading.
You may keep this question paper. We suggest that you record your answers so that you may compare them against
the answer key which will be posted on the Bulletin Board at the north (river) end of the 200 floor of Parker
Chemistry Building AND on CHEM 1300 WebCT Lecture site immediately after the examination.
NOTE: Students are not permitted to bring in any unauthorized materials to this examination. This includes but is not
limited to books, notes, or any electronic device capable of wireless communication and/or storing information (e.g.,
translator, cell phone, pager, PDA, MP3 units, etc.) However, students are allowed a calculator (BUT no text, formulas,
etc. may be programmed into memory).
Students having any such device at their seat will automatically receive a score of “0” on this examination.
Paper:
1.
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CHEM 1300 University I Chemistry: Models
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Aluminium reacts with dioxygen to produce aluminium oxide.
If 6.00 g of aluminium is reacted with 6.00 g of dioxygen, what is the maximum mass of aluminium oxide that can be
produced?
a) 22.6 g Al2O3
d) 11.3 g Al2O3
b) 19.2 g Al2O3
e) 9.40 g Al2O3
c) 12.7 g Al2O3
2.
A substance that cannot be chemically broken down into simpler substances is considered
a) a homogeneous mixture.
d) an element.
b) a heterogeneous mixture.
e) a compound.
c) an electron.
3.
A chemical change
a) occurs when methane gas is burned.
b) occurs when paper is shredded.
c) occurs when water is vaporized.
d) occurs when salt is dissolved in water.
e) occurs when kool-aid is stirred into water.
4.
By using a mass spectrometer a scientist measured the isotopic composition of an element in a sample as:
amu 63.954
65.947
66.948
67.949
69.946
% abundance 48.87
27.62
4.12
18.71
0.69
From the atomic masses given in the Periodic Table (within 5%), this element can be identified as:
a) Cu
b) Ga
c) Ni
d) Ti
e) Zn
5.
Which of the following statements about isotopes is TRUE?
a) Isotopes of the same element differ only in the number of electrons they contain.
b) An isotope of an atom with a larger number of neutrons is larger than an isotope of the same atom that
contains fewer neutrons.
c) Isotopes of the same element have the same mass.
d) Isotopes of the same element don't usually have the same properties.
e) Some elements have 3 or more naturally occurring isotopes.
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6.
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The correct formula for copper(II) sulfate pentahydrate is
a) Cu2SO3•H5
b) Cu2S•H2O
c) CuS•5H2O
d) (CuSO4)5
e) CuSO4•5H2O
7.
Determine the molarity of a solution formed by dissolving 468 mg of MgI2 in enough water to yield 50.0 mL of
solution.
a) 0.0297 mol/L
b) 0.0337 mol/L
c) 0.0936 mol/L
d) 0.0107 mol/L
e) 0.0651 mol/L
8.
Which element is being reduced in the following reaction?
2 Li(s) + Fe(C2H3O2)2(aq) → 2 LiC2H3O2(aq) + Fe(s)
a) O
b) H
c) C
d) Fe
e) Li
9.
Which statement about strong acids is false?
a) Strong acids are strong electrolytes.
b) Strong acids are very concentrated.
c) Strong acids are almost entirely converted to ions when dissolved in water.
d) Nitric acid is a strong acid.
e) Hydrochloric acid is a strong acid.
10. Which one of the following statements is INCORRECT?
a) The isotope symbolized by
184
76 Os
has 76 protons, 76 electrons and 108 neutrons.
79
−
b) The symbol representing the anion of bromine that has 35 protons, 44 neutrons and 36 electrons is 35 Br .
c) The isotope symbolized by
3+
54
24 Cr
has 21 electrons, 30 neutrons and 24 protons.
d) The ion V3+ has fewer protons in its nucleus than does the ion Zn2+.
e) The ion Mn2+ has more electrons than does the ion Co3+.
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CHEM 1300 University I Chemistry: Models
11. Nitrogen-14,
14
7N
, is the most abundant stable isotope of nitrogen.
Nitrogen-12,
12
7N
, decays with a half-life of 0.012 s.
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Which one of the following is the most likely process for the radioactive decay of this isotope?
1
0
a) α emission
d)
b) β emission
e) fission
c)
0
+1
n emission
e emission
12. Which one of the following statements is correct?
a) An α (alpha) particle has two (2) electrons in a 1s orbital.
0
b) A β (beta, –1e ) particle is a negatively charged neutron.
0
c) A positron ( +1e ) has a mass equal to that of a proton.
0
0
d) Either positron ( +1e ) or beta ( –1e ) emission produces nuclei of elements that are different from those of the
emitting nuclei.
e) Nuclei decaying by β emission have shorter half-lives than those decaying by α emission.
13. Which one of the following best completes the following statement?
The most penetrating type of radioactivity is
(A)
, and the least penetrating is
(B) .
a) A = alpha particles; B = gamma rays
b) A = beta particles; B =alpha particles
c) A = beta particles; B = gamma rays
d) A =gamma rays; B = alpha particles
e) A = gamma rays; B = beta particles
14. Determine the identity of the daughter nuclide from an electron capture by 230Pa.
a) 229Th
b) 234Np
d) 230U
e) 230Th
c) 226Ac
15. Which of the following statements are TRUE?
a) If N/Z ratio is too high, there are too many protons and the nuclide will undergo positron emission or electron
capture.
b) If N/Z ratio lies somewhere below 1, the nuclide is stable.
c) If N/Z ratio is too low, there are too many neutrons and the nuclide will undergo beta decay.
d) The valley of stability is the geographic location where many of the known nuclides were first discovered.
e) None of the above are true.
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16. A patient about to undergo a PET scan is injected with a drug containing the positron emitter
11
6C
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with a half-life of
24 min. An instrument malfunction delays the PET scan for two hours. What fraction of the original amount of
11
6C
will remain in the patient at the end of the two-hour period?
a) 1/8
b) 1/16
c) 1/32
d) 1/64
e) 1/128
17. The following reaction represents what nuclear process?
235
U + 1n →
139
Ba + 94Kr + 3 1n
a) nuclear fission
b) nuclear fusion
c) electron capture
d) alpha decay
e) beta emission
18. The age of an ancient tree trunk is estimated using radiocarbon dating. If the trunk has a C-14 decay rate that is 34%
of what it is in living plants, how old is the trunk? The half-life of C-14 is 5730 years.
a) 2.9 × 104 years
b) 1.9 × 104 years
c) 8.9 × 103 years
d) 5.3 × 103 years
e) 1.7 × 102 years
19. Evidence exists that atoms of the heavy elements are generated in the evolutionary processes occurring in stars. The
heavy elements, i.e., those beyond iron in the periodic table, are thought to be generated
a) during all stages of stellar evolution.
b) during the "hydrogen burning" phase (the stage our sun is at).
c) during the "helium burning” phase (red giant).
d) during the final stages of a dying star when its core collapses liberating large numbers of protons and neutrons
(supernova).
e) during the stage known as a supergiant, i.e. in the same process generating the elements up to iron.
20. Which one of the following observations suggests that our sun is at least a “second generation” star?
In our sun,
a) helium is present.
b) elements heavier than iron are present.
c) hydrogen fuses to helium.
d) helium fuses to beryllium and then to carbon.
e) neutrons decay to protons, electrons, and neutrinos.
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21. According to the stellar nucleosynthesis of elements model, which one of the following is the correct order of the steps
in the formation of the elements?
Process I.
formation of oxygen-16
Process II. helium burning
Process III. hydrogen burning
Process IV. reaction of beryllium-8 with helium-4
Process V. successive fusions up to calcium-40
a) Process III, then II, IV, I, and finally V
b) Process III, then V, I, IV, and finally II
c) Process II, then IV, I, V, and finally III
d) Process II, then III, I, IV, and finally V
e) Process I, then IV, V, II, and finally III
22. Which one of the following reactions represent a photosynthetic process?
a) 2CO + O 2 → 2CO 2
b) CH 4 + 2O 2 → CO 2 + 2H 2 O
c) 2H 2 + O 2 → 2H 2 O
sunlight
→ 6O 2 + C 6 H12 O 6
d) 6CO 2 + 6H 2 O   
sunlight
→ 6CO 2 + 6H 2 O
e) 6O 2 + C 6 H12 O 6   
23. Which one of the following statements is correct?
a)
There is a significant exchange of carbon between land and ocean
b) Elements up to iron and nickel are produced during helium burning stage
c)
Hydrogen burning is based on a fission processes
d) The atmosphere is the link between all parts of carbon cycle
e)
None of the above statements are correct
24. Some elements emit light of a characteristic color when they are heated in a flame. Historically, chemists used such
"flame tests" to determine whether specific elements were present in a sample. Characteristic wavelengths for a few
selected elements are:
Ag 328.1 nm
Ca
422.7 nm
K
Au 267.6 nm
Cu
324.8 nm
Mg 285.2 nm
Ba
Fe
372.0 nm
Na
455.4 nm
404.7 nm
589.6 nm
When heated in a flame, a sample of an unknown substance was found to emit light of frequency 9.24 x 1014 s–1.
Which one of the following elements is probably in the sample?
a) Ag
b) Ba
c) Cu
d) K
e) Na
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25. Which of the following sets of quantum numbers is CANNOT occur?
i) n = 3, l = 2, ml = –1
ii) n = 2, l = 3, ml = –1
iii) n = 4, l = 0, ml = –1
iv) n = 5, l = 2, ml = –1
v) n = 3, l = 3, ml = –3
a) only ii)
d) only ii), iii), and v)
b) only iv)
e) all of i), ii), iii, and iv)
c) only ii) and v)
26. Using Hund's Rule, select the electron configuration that represents a correct ground state electronic configuration for
an isolated atom with six (6) electrons:
1s
2s
2p
1s
a)
d)
b)
e)
2s
2p
c)
27. Among the following ions, several pairs are isoelectronic. Identify these pairs
Fe2+
Sc3+
K+
Br–
Co2+
Sr2+
O2–
Zn2+
a) Fe2+and O2–; K+ and Br–
d) Fe2+ and Co2+; Sr2+ and Zn2+
b) Co2+ and Sr2+; O2– and Zn2+
e) Sc3+ and K+; Br– and Sr2+
c) Sc3+ and K+; Br– and Co2+
28. Which of the following species is (are) PARAMAGNETIC?
Al+
Ca2+
F–
S2–
a) Al+ only
d) all of Al+, Ca2+, F–, and S2–
b) F– only
e) none of Al+, Ca2+, F–, and S2–
c) both Ca2+and S2–
29. Which of the following transitions (in a hydrogen atom) represent emission of the longest wavelength photon?
a) n = 1 to n = 2
b) n = 3 to n = 1
c) n = 3 to n = 4
d) n = 4 to n = 2
e) n = 5 to n = 4
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30. Place the following types of electromagnetic radiation in order of increasing wavelength.
Visible light
gamma rays
microwaves
a) gamma rays < microwaves < visible light
b) microwaves < visible light < gamma rays
c) microwaves < gamma rays < visible light
d) visible light < gamma rays < microwaves
e) gamma rays < visible light < microwaves
31. How many orbitals are contained in the third principal level (n=3) of a given atom?
a) 9
b) 3
c) 18
d) 7
e) 5
32. Which of the following occur as the wavelength of a photon increases?
a) the frequency decreases
b) the energy increases
c) the speed decreases
d) Planck's constant decreases
e) None of the above occurs as the wavelength of a photon increases.
33. Determine the shortest frequency of light required to remove an electron from a sample of Ti metal, if the ionization
energy of titanium is 3.14 × 103 kJ/mol.
a) 7.87 x 1015 Hz
b) 4.74 x 1015 Hz
c) 2.11 x 1015 Hz
d) 1.27 x 1015 Hz
e) 6.19 x 1015 Hz
34. Give the ground state electron configuration for Mg2+.
a) 1s2 2s2 2p6 3s2
b) 1s2 2s2 2p6
c) 1s2 2s2 2p6 3s2 3p2
d) 1s2 2s2 2p6 3s2 3p6
e) 1s2 2s2 2p6 3s1
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35. How many valence electrons do the alkali metals possess?
a) 1
b) 2
c) 7
d) 6
e) 8
36. Choose the statement that is TRUE.
a) Outer electrons efficiently shield one another from nuclear charge.
b) Core electrons efficiently shield outer electrons from nuclear charge.
c) Valence electrons are most difficult of all electrons to remove.
d) Core electrons are the easiest of all electrons to remove.
e) All of the above are true.
37. An element forms an oxide with formula A2O. Among the choices below, in which of the main groups of the periodic
table can the element A be located?
a) I or VII
b) I or VI
c) II or VII
d) II or VI
e) III or V
c)
Atomic number
e)
Atomic number
Atomic number
Atomic radius
d)
Atomic radius
Atomic radius
b)
Atomic radius
a)
Atomic radius
38. From the graphs below, select the one which most nearly depicts the correlation of atomic radius with atomic number
for elements in the same family (or group) of the periodic table.
Atomic number
Atomic number
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39. The ionization energy of the elements in the second (2nd) period of the periodic table is shown in the figure below:
Ionization energy / MJ/mol
2.5
2.0
N
1.5
O
Be
1.0
B
0.5
0.0
2
3
4
5 6 7 8 9 10 11
Atomic number, Z
Which one of the following is the best explanation for the observation:
The first ionization energy of boron, B, is lower (less) than that of beryllium Be.
a) Atoms with all half-filled and/or completely filled subshells are particularly stable.
b) Hund’s rule requires that the energy be less.
c) Electrons in “p” orbitals of the atoms of both of the elements are paired.
d) Electrons in “s” orbitals of the atoms of both of the elements are paired.
e) Beryllium has an even nuclear charge while boron has an odd nuclear charge.
40. In which one of the following pairs is the element of HIGHER electronegativity listed first?
a) Cl > F
b) O > F
c) P > S
d) C > Si
e) P > O
41. An element X, has the electron configuration [Ne] 3s2 3p3. The formula for the binary compound that this element
forms with calcium, Ca, is
a) CaX
b) Ca2X
c) CaX2
42. Which of the following represent the Lewis symbol for N?
a)
b)
c)
d)
e)
d) Ca2X3
e) Ca3X2
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43. In which one of the following pairs do BOTH molecules have a triple bond in their molecular structure (according to
the octet rule)?
a) SO2 and SCl2
d) O2 and SO2
b) CO and N2
e) SO2 and N2
c) OF2 and O2
44. Choose the best Lewis structure for CH2Cl2.
a)
b)
c)
d)
e)
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CHEM 1300
University I Chemistry: Modeling
Fall 2007
ANSWERS to Mid-term Examination (October 24, 2007)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
D)
D)
A)
E)
E)
E)
B)
D)
B)
E)
C)
D)
D)
E)
E)
C)
A)
C)
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
D)
B)
A)
D)
D)
C)
D)
B)
E)
E)
E)
E)
A)
A)
A)
B)
A)
B)
37.
38.
39.
40.
41.
42.
43.
44.
A)
C)
A)
D)
E)
A)
B)
B)