1. No category

Chemistry 1100A
1.
Test # 2
November 12, 2011
Code 000
Page 1
A natural sample of element X contains two isotopes, the masses of which are
68.95 amu and 70.95 amu. The average atomic mass of this element is 69.75
amu.
What is the percentage abundance of each of the two isotopes? The lighter
isotope is listed first.
A) 60, 40
B) 52, 48
C) 30, 70
D) 56, 44
E) 70, 30
2.
The molecule shown is acetylsalicylic acid. For a 100 g sample of acetylsalicylic
acid, which one of the following statements is correct ?
(NA = 6.02 x 1023)
A) The sample contains 35.5% oxygen by mass.
B) The sample contains 21 moles of atoms.
C) The sample contains 3.34 x 1023 atoms.
D) The sample contains 3.33 moles of hydrogen atoms.
E) The sample contains more oxygen than carbon by mass.
3.
For the reaction:
A + 2B + 3C 2D
2.00 moles of A are reacted with 3.00 moles of B and 5.00 moles of C. After the
reaction goes to completion, which one of the following statements is correct?
A) One-half of a mole of C remains unreacted.
B) One mole of A remains unreacted.
C) No A remains unreacted.
D) Two-thirds of a mole of B has reacted.
E) One-third of a mole of C remains unreacted.
Chemistry 1100A
4.
Test # 2
November 12, 2011
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Page 2
All of the chloride in an aqueous solution of CaCl2 was precipitated completely as
AgCl. If 0.715 g of AgCl is obtained from 25.0 mL of aqueous CaCl2, what was
the molarity of the CaCl2 solution?
A) 0.100
B) 0.0250
C) 0.0500
D) 0.200
E) 0.400
5.
What is the pH of a solution prepared by mixing 100 mL of 0.250 M HNO3 with
150 mL of 0.100 M Ba(OH)2?
A) 12.30
B) 11.70
C) 1.70
D) 2.00
E) 7.00
Chemistry 1100A
6.
Test # 2
November 12, 2011
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Page 3
Which one of the following sets of quantum numbers is correct for a ground state,
valence shell electron in tin, Sn?
A) n = 5, l = 1, ml = −1, ms = +½
B) n = 5, l = 0, ml = 1, ms = +½
C) n = 4, l = 1, ml = −1, ms = -½
D) n = 4, l = 2, ml = 3, ms = -½
E) n = 5, l = 0, ml = 2, ms = +½
7.
Which of the following statements is/are correct for an atom of antimony, Sb, in
the ground state?
i)
It has three unpaired electrons
ii) The highest energy electron is in a 5p orbital
iii) The highest energy electron could have a value of ml of −2
iv) It is isoelectronic with In2+
A) i) and ii) only
B) i), ii) and iv) only
C) ii) and iv) only
D) iii) and iv) only
E) i), iii) and iv) only
Chemistry 1100A
8.
Test # 2
November 12, 2011
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Page 4
Which one of the following species in the ground state has the greatest number
of unpaired electrons?
A) Mn2+
B) Fe2+
C) Cr3+
D) Co2+
E) Zn2+
9.
Based on periodic trends, how many of the following statements is/are correct?
i) The correct order for decreasing atomic radius is Ca > Mg > Na.
ii) The correct order for decreasing first ionization energies is Rb > K > Na.
iii) In the ground state, O2−, S2− and Se2− are isoelectronic with each other.
iv) CaO has a higher melting point than MgO.
A) 0
B) 1
C) 2
D) 3
E) 4
10.
Which one of the following statements best explains why atomic oxygen has a
lower first ionization energy than atomic nitrogen?
A) Oxygen has a pair of electrons in one p orbital, resulting in repulsion.
B) Oxygen has more electrons than nitrogen.
C) Oxygen has a larger effective nuclear charge than nitrogen.
D) Nitrogen has a triple bond, so it is harder to ionize than oxygen.
E) Nitrogen must gain more electrons than oxygen to obtain a full octet.
Chemistry 1100A
11.
Test # 2
November 12, 2011
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Page 5
Which of the following statements concerning nitrate ion, NO3−, is/are correct?
i) It has an average bond order of 5/3.
ii) The best Lewis structure of NO3−, has at least one O atom with a formal
charge of −1.
iii) Three equivalent resonance structures can be drawn.
A) ii) and iii) only
B) i) and iii) only
C) All statements are correct
D) i) and ii) only
E) iii) only
12.
Consider the Lewis structure show below. Which one of the following elements
could X be?
A) I
B) Se
C) F
D) N
E) Si
Chemistry 1100A
13.
Test # 2
November 12, 2011
Code 000
Page 6
Which one of the following is the best Lewis structure for the thiocyanate ion,
SCN−?
A)
B)
S
C
N
C)
D)
2-
S
C
N
E)
14.
Consider the oxalate ion, C2O42−, which has a C – C bond. Which of the following
statements concerning the best Lewis structure for this ion is/are correct?
i) Two oxygen atoms each have a formal charge of −1.
ii) There are only two equivalent resonance structures.
iii) The average bond order of each carbon-oxygen bond is 3/2.
A) i) and iii) only
B) ii) only
C) iii) only
D) i) and ii) only
E) ii) and iii) only
Chemistry 1100A
15.
16.
November 12, 2011
Code 000
The ion XO42― has a see-saw molecular geometry.
What is a possible identity of X?
A)
Kr
B)
S
C)
Ne
D)
Si
E)
Br
How many of the following molecules are polar?
PO43−
17.
Test # 2
A)
3
B)
1
C)
2
D)
0
E)
4
TeF4
CCl4
BrF5
CH3OCH3
Which one of the following molecules contains a bond angle of 90°?
A) XeF4
B) CF3+
C) SF4
D) H3O+
E) PCl3
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Chemistry 1100A
18.
Test # 2
November 12, 2011
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Page 8
Consider the hypothetical molecule BrH3. Which one of the following statements
is most likely to be correct?
A) An sp3d hybrid orbital on Br overlaps with a 1s orbital on H to form a σ bond.
B) An sp2 hybrid orbital on Br overlaps with a 1s orbital on H to form a σ bond.
C) A p orbital on Br overlaps with a 1s orbital on H to form a σ bond.
D) An sp3d2 hybrid orbital on Br overlaps with a 1s orbital on H to form a σ bond.
E) An sp3 hybrid orbital on Br overlaps with a 1s orbital on H to form a σ bond.
19.
Which one of the following statements correctly describes the orbital overlap
which forms the indicated bond?
A) Two sp hybrid orbitals overlap to form a σ bond; four p orbitals overlap to
form two π bonds.
B) Four p orbitals overlap to form the triple bond.
C) Four sp3 hybrid orbitals overlap to form a π bond.
D) Four sp2 hybrid orbitals overlap to form two σ bonds.
E) Two sp2 hybrid orbitals on carbon overlap with two sp hybrid orbitals on
nitrogen to form two σ bonds and a π bond.
Chemistry 1100A
20.
Test # 2
November 12, 2011
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Page 9
How many of the following statement(s) is/are correct about the amino acid
histidine?
O
N
OH
HN
NH 2
i) It contains 6 non-bonding electron pairs
ii) The geometry of the C at the C=O group is trigonal planar
iii) Its molecular formula is C6H9N3O2
iv) The hybridization of the N at the top of the ring (the one without the H)
is sp2
A) 3
B) none
C) 1
D) 4
E) 2
21.
Consider the XeF3− ion. Which one of the following statements best describes
this ion?
A) The Xe atom is sp3d2 hybridized. The participating atomic orbitals are 5s, 5p
and 5d. The molecule has a T-shape.
B) The Xe atom is sp3d2 hybridized. The participating atomic orbitals are 5s, 5p
and 4d. The molecule has a T-shape.
C) The Xe atom is sp3d hybridized. The participating atomic orbitals are 5s, 5p
and 4d. The molecule has a T-shape.
D) The Xe atom is sp3d hybridized. The participating atomic orbitals are 5s, 5p
and 5d. The molecular has a trigonal planar shape.
E) The Xe atom is sp3 hybridized. The participating atomic orbitals are 5s and 5p.
The molecule has a trigonal pyramidal shape.
Chemistry 1100A
22.
Test # 2
November 12, 2011
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Page 10
How many of the following five species are paramagnetic?
Br−
N2
Ag
Be2+
Cu+
A) 2
B) 3
C) 1
D) 4
E) 5
23.
Both Li and Be occur as metals under normal conditions. Consider the stability
predictions that could be made using Molecular Orbital Theory for the diatomic
gases Li2 and Be2 . Which of the following statements is/are correct?
i)
Li2 could exist.
ii) Be2 could exist.
iii) Both Li2 and Be2 could exist.
iv) The bond order in Li2 is 1.
v) The bond order in Be2 is 2.
A) i) and iv) only
B) ii) and v) only
C) i), iii), iv) and v) only
D) iii), iv) and v) only
E) None of the statements is correct.
Chemistry 1100A
24.
Test # 2
November 12, 2011
Code 000
The following is a correctly drawn MO diagram. Which one of the following
ground state species in A) – E) could this diagram describe?
A) N2−
B) O2
C) P2−
D) B2+
E) F2+
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Chemistry 1100A
25.
Test # 2
November 12, 2011
Which of the following is/are σ-type orbital(s)?
A) I and II only.
B) II only.
C) I only.
D) II and IV only.
E) I and II and IV only.
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Chemistry 1100A
26.
Test # 2
November 12, 2011
Code 000
Page 13
In which one of the following molecules is hydrogen bonding NOT the
predominant intermolecular force?
A)
B)
C)
D)
E)
27.
Which one of the following statements is most likely to be a requirement for a
primary standard?
A) It must be a solid with a very high degree of purity.
B) It must be a solid with only one acidic hydrogen.
C) It must be a solid which readily absorbs water.
D) It must be a solid which determines the equivalence point of a titration.
E) It must be a solid insoluble in water.
Chemistry 1100A
28.
Test # 2
November 12, 2011
Code 000
Page 14
When titrating an acid with a base (ie, the base is the titrant) using
phenolphthalein as the indicator, the solution, at the equivalence point, will….
A) be colourless.
B) turn pale pink.
C) turn white.
D) turn purple.
E) bubble.
29.
In the Molar Volume of Nitrogen experiment, why was it necessary to determine
the “corrected” volume?
A) The corrected volume is the volume of gas that would be collected at some
specific reference conditions.
B) The corrected volume is calculated using the ideal gas constant, R.
C) The corrected volume is always smaller than the experimental volume.
D) The corrected volume is always more accurate than the experimental volume.
E) We have to calculate a volume as it is impossible to measure the actual
volume of gas collected.
30.
In the Molar Volume of Nitrogen experiment, the temperature of the water was
recorded in addition to the temperature of the gas. Why?
A) The temperature of the water is needed to determine the vapour pressure of
the water.
B) The temperature of the water is more accurate than the temperature of the
gas.
C) The average of the two temperatures gives the most accurate temperature to
use.
D) The pressure cannot be equalized until the temperatures are the same.
E) To ensure that the water and the gas were in equilibrium with each other.