Chemistry 1100a Test #2, November 2010
Page 1
Before starting the test, be sure that you have correctly entered:
Your student number
Your exam code
1.
All of the chlorine in 1.000 g of a mixture of SO 2 and SO2Cl2 was converted to
AgCl. The mass of the AgCl collected was 0.491 g. How many grams of SO2
were in the mixture of SO2 and SO2Cl2?
A) 0.769
B) 0.075
C) 0.509
D) 0.538
E) 0.754
2.
Metallic Zn is produced from ZnS ore by the following two-step process:
2 ZnS + 3 O2
ZnO + C
2 ZnO + 2 SO2
Zn + CO
If a ZnS ore contains 4.00% ZnS by weight, what is the maximum number of
grams of Zn that can be produced from 5.00 kg of ZnS?
A) 134
B) 65.4
C) 167
D) 268
E) 654
Chemistry 1100a Test #2, November 2010
3.
Page 2
10.0 mL of a solution of H2SO4 is diluted to 1.00 L. The final solution has a pH of
2.000. What is the mass percent of H2SO4 in the original solution if the original
solution has a density of 1.033 g mL ?
A) 4.74
B) 4.90
C) 9.80
D) 10.1
E) 9.49
4.
Which one of the following is a possible set of quantum numbers for a p electron
in the Zn atom in the ground state?
ml
ms
n
l
A)
3
1
B)
4
1
1
½
C)
3
2
3
+½
D)
2
1
2
+½
E)
3
3
2
½
+½
Chemistry 1100a Test #2, November 2010
5.
Which one of A
Page 3
E is the correct orbital diagram for Co2+ in the ground state?
A)
4s
3d
4s
3d
4s
3d
4s
3d
4s
3d
B)
C)
D)
E)
6.
How many of the statements below are correct for the Se atom in the ground
state?
It is paramagnetic.
The highest-energy electron is in an orbital with four nodes.
The highest-energy electron could have an ml value of +2.
It is isoelectronic with Br .
A) 1
B) 2
C) 3
D) 4
E) None of the statements are correct
Chemistry 1100a Test #2, November 2010
7.
Page 4
Based on periodic trends, which one of A
ionization energy?
E is the correct order of decreasing
A) Be > Sr > Rb
B) Rb > Be > Sr
C) Rb > Sr > Be
D) Sr > Rb > Be
E) Be > Rb > Sr
8.
How many of the statements below are correct for the molecule FOOF?
The best Lewis structure has zero formal charge on each atom.
Both O atoms have a trigonal planar electronic arrangement.
The bond order of the oxygen-oxygen bond is 1.
The Lewis structure does not contain any
bonds.
A) 3
B) 2
C) 1
D) 4
E) None of the statements are correct
9.
The correct Lewis structure of XO4
is shown below. What could element X be?
A) Se
B) P
O
C) Br
O X O
D) Si
O
E) N
Chemistry 1100a Test #2, November 2010
10.
Page 5
Which two of the following are best resonance structures of N2O? (Formal
charges are not indicated in the Lewis structures.)
N N O
N N O
N N O
N N O
1
2
3
4
A) 2 and 4
B) 2 and 3
C) 1 and 3
D) 3 and 4
E) 1 and 2
11.
Which statement about SiF4, SeF4, and KrF4 is most correct?
A) They have different molecular shapes.
B) They are all of VSEPR type AX4.
C) They are all nonpolar molecules.
D) They all have the same number of nonbonding electrons.
E) They all have the same number of regions of
electron density at the central atom.
12.
Which one of A
A) BF3
B) NH3
C) PCl3
D) BrF3
E) H3O+
E contains a bond angle that is closest to 120°?
Chemistry 1100a Test #2, November 2010
13.
Page 6
Which one of the following has a trigonal bipyramidal electronic arrangement but
a see-saw shape?
A) XeO2F2
B) BrF5
C) PCl5
D) PCl4+
E) XeF4
14.
How many of the species below are polar (have a net dipole moment)?
CO3
SF4
CF4
CH2F2
A) 2
B) 1
C) 3
D) 4
E) None of them
15.
Acetaldehyde, shown on the right, is the first compound formed
when ethanol is metabolized. Which statement about
acetaldehyde is correct?
A) The bond between carbons 1 and 2 can
freely rotate without breaking the bond.
B) Carbon 2 is sp-hybridized.
C) Acetaldehyde contains only three
D) The oxygen atom is sp-hybridized.
E) It has a molecular formula of C2HO.
bonds.
O
H
carbon 1
carbon 2
Chemistry 1100a Test #2, November 2010
16.
Page 7
Which one of the following statements is NOT correct?
A) An sp2-hybridized carbon can form two
B) The two
bonds.
bonds in acetylene (HCCH) are perpendicular to each other.
3
C) When sp hybridization occurs, the resulting hybrid orbitals are degenerate.
D) The hydrogen atoms in CH4 are not hybridized.
E) Bonds that are spherically symmetrical about the bond axis are
17.
bonds.
Which statement about diborane, B2H6, is NOT correct?
A) It contains four 3-centre-2-electron bonds.
B) It contains two bridging hydrides.
C) The two boron atoms are sp3-hybridized.
D) It contains four terminal hydrogens.
E) It contains a total of 12 valence electrons.
18.
Which one of the following statements about molecular orbital theory is correct?
A)
* molecular orbitals are formed by the sideways overlap of out-of-phase p
orbitals and result in the formation of a new node between the nuclei.
B) An oscillating wave alternates between negative and positive charge.
C) The electrons that bond two nuclei are deemed to be localized between the
two nuclei.
D) The number of molecular orbitals formed is equal to half of the total number of
atomic orbitals used to form the molecular orbitals.
E) None of the other statements are correct.
Chemistry 1100a Test #2, November 2010
19.
Page 8
Which one of the following changes in conditions is NOT possible for a fixed
number of moles of an ideal gas?
A) Increasing both the pressure and the volume while
keeping the temperature constant
B) Increasing both the pressure and the temperature while
keeping the volume constant
C) Increasing both the volume and the temperature while
keeping the pressure constant
D) Decreasing only the volume while decreasing the temperature
E) Decreasing only the pressure while decreasing the temperature
20.
Hot-air balloons rise because the air inside the balloon is warmer than the air
outside of the balloon. Because a hot-air balloon is not sealed, the pressure of
the air inside a hot-air balloon is equal to atmospheric pressure. Which of the
following statements is/are correct?
1. The air inside the balloon has a higher molar volume than the air outside
of the balloon.
2. The air inside the balloon has a lower average kinetic energy than the air
outside of the balloon.
3. The air inside the balloon has a lower density than the air outside of the
balloon.
A) 1 and 3 only
B) 3 only
C) 2 and 3 only
D) 1 only
E) All statements are correct
Chemistry 1100a Test #2, November 2010
21.
Page 9
Consider the parameters P, T, V, and n for an ideal gas. If any two of these
parameters are fixed, which of the following plots correctly shows the relationship
between the two remaining parameters?
1
2
T
3
V
P
P
P
V
4
V
P
T
A) 2, 4, and 5 only
B) 1 and 2 only
C) 4 only
D) 3 and 4 only
E) 3, 4, and 5 only
5
T
Chemistry 1100a Test #2, November 2010
22.
Page 10
A gaseous mixture at 300 K has a total pressure of 90.0 kPa. If the mixture
contains 0.30 mol of N2 and an unknown quantity of CO2, and the partial
pressure of N2 is 54.0 kPa, how many moles of CO2 are in the mixture?
A) 0.20
B) 0.050
C) 0.15
D) 0.25
E) 0.10
23.
A sealed, 2.0 L flask contains 1.0 L of liquid water and 0.100 g of helium gas at
50 °C. At equilibrium, what is the mole fraction of helium in the gas phase? (The
vapour pressure of water at 50 °C is 12.3 kPa.)
A) 0.845
B) 1.00
C) 2.25 × 10
D) 4.50 × 10
E) 0.732
24.
If the root mean square (rms) speed of nitrogen gas is 1.74 times higher than that
of an unknown gas at 25°C, what is the molar mass of the unknown gas?
A) 85
B) 49
C) 9.0
D) 16
E) 42
Chemistry 1100a Test #2, November 2010
25.
Page 11
Which one of the following pieces of apparatus is used to most accurately deliver
a specific volume of liquid?
A) Transfer pipette
B) Beaker
C) Volumetric flask
D) Squirt bottle
E) Graduated cylinder
26.
In the redox experiment, it was unnecessary to use an indicator to show the end
point of the titration. Why?
A) The end point is indicated by the excess of pink-coloured KMnO4.
B) Indicators do not work for redox titrations.
C) The pink colour from the iron pills disappears at the end point.
D) Fe3+ turns pink at the end point.
E) The formation of MnO2 at the end point produces a brown colour.
Chemistry 1100a Test #2, November 2010
Page 1
Question 1
Draw the overlap of atomic and/or hybrid orbitals to show the bonding in C2H4. Label, on
your diagram, all atomic orbitals, hybrid orbitals, bonds, and bonds.
H
H
C
H
C
H
Chemistry 1100a Test #2, November 2010
Page 2
Question 2
A. Draw a molecular orbital diagram for the N2 molecule. Indicate, on the MO diagram,
the , *, , and * molecular orbitals, and the electrons.
B. Based on your MO diagram, rank the following in the order of increasing molecular
orbital bond order: N2, N2 , N2
Lowest
Middle
Highest
Chemistry 1100a Test #2, November 2010
Page 3
Question 3
Arrange the following liquids in the order of increasing boiling point. Name the strongest
intermolecular force present in each of these liquids.
O
OH
Lowest
Compound
Strongest
intermolecular
force
H
Middle
Highest
Chemistry 1100a Test #2, November 2010
Page 4
Question 4
25.0 kPa of CO are combined with 15.0 kPa of O2 and reacted according to the reaction
equation shown below. What is the mole fraction of CO2 after the reaction is complete?
Assume that the temperature and volume of the system remain constant.
CO(g) + ½ O2(g)
CO2(g)
Answer: ___________________
Chemistry 1100a Test #2, November 2010
Page 5
Question 5
A.
Concisely define these two terms:
Equivalence point
End point
B.
Is solid NaOH a good primary standard? Why or why not?
C.
What is the volume indicated by the burette shown below, to two decimal places?
The meniscus is indicated by the dotted line.
14
15