Canadian International Matriculation Programme
Sunway University College
SCH4U CHEMISTRY FINAL EXAMINATION
Date:
Wednesday, November 26, 2008
Time:
11:30 a.m. – 1:30 p.m.
Length:
2 Hours
Lecturer:
Dr Sharlene Lee
Student Name: __________________________Section/Period: _______
INSTRUCTIONS TO STUDENTS:
1.
2.
3.
4.
5.
6.
Check that your examination has 17 typed pages, including the cover page.
Answer all questions in the spaces provided.
Marks are indicated in the right-hand margin in brackets.
You may use a scientific calculator.
You may use a dictionary.
Chemistry Tables are provided on pages 15 to 17. Please tear them off now for easier
referral.
7. There are four sections to the exam. Read instructions to each part carefully.
STRUCTURE/EVALUATION
PART A
Multiple Choice (Knowledge/Understanding)
15 marks, allow 20 minutes
PART B
Communications Response
(Knowledge/Understanding, Inquiry,
Communication)
18 marks, allow 25 minutes
PART C
Quantitative/Analytic (Inquiry, Making
Connections)
29 marks, allow 40 minutes
PART D
Extended Response (Inquiry, Communication,
Making Connections)
27 marks, allow 35 minutes
TOTAL
89 marks, 2 hours
2
Part A: Multiple Choice (K/U, 15 marks, allow 25 minutes)
On the line to the left of the question, identify the letter of the choice that best completes the
statement, or answers the question.
_______
_______
1.
Name the following compound.
a.
b.
c.
d.
e.
1-methyl-3,4-dibromocyclopentene
3-methyl-1,2-dibromocyclopentene
3-methyl-4,5-dibromocyclopentene
3-methyl-3,4-dibromocyclopentene
2-methyl-3,4-dibromocyclopentene
2.
What is the best explanation for the difference in boiling points for methane and ethane?
Boiling point, CH4 = -161.5 oC
_______
_______
Boiling point, CH3CH3 = -88.6 oC
a.
b.
c.
d.
e.
Dispersion forces are greater for ethane.
Dispersion forces are greater for methane.
Hydrogen bonding is stronger in ethane.
Hydrogen bonding is stronger in methane.
Dipole-dipole forces are stronger in ethane.
3.
Which two compounds react to form an ester?
a.
b.
c.
d.
e.
a carboxylic acid and an alcohol.
an alcohol and an aldehyde.
an alcohol and a ketone.
a carboxylic acid and a ketone.
an aldehyde and a carboxylic acid.
4.
Which electron configuration represents a reactive non-metallic element?
a.
b.
c.
d.
e.
1s2 2s2 2p6 3s2 3p5
1s2 2s2 2p6 3s2 3p1
1s2 2s2 2p6 3s2
1s2 2s2 2p6 3s2 3p6
1s2 2s2 2p6 3s2 3p6 4s2
3
_______
5.
Which of the statements about the compound shown here is false?
O
CH2 C – OH
_______
a.
b.
c.
d.
e.
Its empirical formula is C4H4O.
It contains the carboxylic acid functional group.
It is an aromatic compound.
Its molecules are non polar.
Hydrogen bonding would occur between molecules of this substance.
6.
The outer electron configuration of an element is: ………….xs2xp3
where x is the element’s period number. To which group of the periodic table does this
element belong?
_______
_______
a.
b.
c.
d.
e.
x
2
3
4
5
7.
A solid compound consists of ions bound in a crystal lattice. Which property would you
not expect this solid to have?
a.
b.
c.
d.
e.
high melting point
good conductivity in the solid state
hard
soluble in a polar solvent
brittle
8.
Which of the following compounds is held together by London dispersion forces?
a.
b.
c.
d.
e.
KI
Na2O
H2O
CO2
NH3
________ 9.
a.
b.
c.
d.
e.
Which of the following observations could not be explained by hydrogen bonding?
The boiling point of H2O (l) is higher than that of H2S (g).
Ammonia (NH3) is very soluble in H2O (l).
Water mixes readily with CH3OH (l).
Salt (NaCl) is very soluble in water.
Propanol has a higher boiling point than propanone.
4
_______
10.
Which statement describes an exothermic reaction?
a.
The energy absorbed in bond breaking is more than the energy released in bond
formation.
The energy absorbed in bond breaking is less than the energy released in bond
formation.
The system absorbs energy.
The surroundings cool down.
The potential energy of the reactants is less than the potential energy of the products.
b.
c.
d.
e.
_______
_______
11.
For an endothermic reaction, what does the activation energy of the reverse reaction
equal?
a.
b.
c.
d.
e.
The activation energy of the forward reaction
The heat of reaction minus the activation energy of the forward reaction
The activation energy of the forward reaction minus the heat of reaction
The heat of reaction plus the activation energy of the forward reaction
The heat of reaction minus the activation energy of the reverse reaction
12.
N2 (g), CO2 (g) and H2O (l) is added to a sealed container. After some time the
following chemical equilibrium is established.
2CO2 (g) + 2H2O (l) ↔ 3H+ (aq) + HCO3- (aq) + CO32- (aq)
Which of the following changes would increase the equilibrium partial pressure of CO2?
_______
_______
a.
b.
c.
d.
e.
removing some of the N2 (g).
Adding some base.
Adding a source of Ca2+ (aq).
Increasing the volume of the system.
Adding some HCl solution.
13.
Which salt produces a basic solution?
a.
b.
c.
d.
e.
KNO2
Na2SO4
NH4ClO4
Ca(NO3)2
NH4CH3COO
14.
Which of the following solutions has the lowest hydronium ion concentration?
a.
b.
c.
d.
e.
1 M HCl (aq)
1 M HNO3 (aq)
H2O (l)
1 M NaCH3COO (aq)
1 M CH3COOH (aq)
5
_______
15.
What is the relationship between the ion product and the solubility product constant
when a precipitate does not form?
a.
b.
c.
d.
e.
Qsp > Ksp
Qsp ≤ Ksp
Qsp < Ksp
Qsp ≥ Ksp
Qsp = Ksp
Part B: Communications Response (K/U, I & C, 18 marks, allow 25 minutes)
Answer ONLY THREE of the following FIVE questions. Write the most appropriate answer in
the space provided. Each response is worth 6 marks.
16.
Complete the following table by giving the IUPAC name, drawing the structural diagram,
identifying the functional group of the compound and the family to which it belongs.
[6 marks]
IUPAC name
octyne
2-methylbutanamide
Structural diagram
Functional group
Family
Alkyne
6
17.
Consider the following graph of ionization energy.
Describe the trend of ionization energy down a group and across a period. Explain this
trend.
[6 marks]
7
18.
Choose ONE molecule from each of the following pairs. For each molecule,
• draw the Lewis structure
• predict the molecular shape
• state whether the molecule will be polar or non-polar
[6 marks]
a.
H2Se or H2CO
b.
PBr5 or PCl3
19.
Choose only TWO of the following groups of substances and list them in increasing
order (from lowest to highest) according to the property stated. Explain your answer.
a.
b.
c.
d.
Polarity: CH3I, CH3F, CH3Br
Strength of dispersion forces: I2, F2, Br2
Boiling point: CH3COOCH3, CH3CH2COOH, CH3CH2CH3
Solubility in water: NH3, CH4, H2S
[6 marks]
8
20.
One of the most important buffer systems in the human blood involves dissolved carbon
dioxide reacting with water to form hydrogen carbonate ions. Explain, using appropriate
equations, how this buffer system works.
[6 marks]
Part C: Quantitative/Analytic (C, I & MC, 37 marks, allow 45 minutes)
For the following questions, write the answer in the space provided. Use complete sentences in
your answers. If the answer requires mathematical calculations, show ALL of your work and the
required UNITS.
21.
Suppose that 0.350 mol of A and 0.520 mol of B are placed a 1.50 L container and the
following hypothetical equilibrium is established. If the equilibrium amount of C is 0.150
mol, what is the equilibrium constant for this reaction?
A(g) + 2B(g) ↔ 3C(g)
[5 marks]
9
22.
A hot pack usually contains calcium chloride or magnesium sulfate. The heat of solution
for calcium chloride is 82.8 kJ.
CaCl2 (s) → Ca2+ (aq) + 2Cl- (aq)
∆Hsolution = –82.8 kJ/mol
a.
40.0 g of calcium chloride is added to 100.0 g water. Calculate the change in the
temperature of the water, assuming that no heat is lost to the surroundings. The heat
capacity of water is 4.18 J/g oC.
[3 marks]
b.
If the initial temperature of the water is 20.0oC, what is the final temperature of the
water?
[1 mark]
c.
Why is it important to control how much calcium chloride is used in a hot pack?
[2 marks]
10
23.
a.
The following data was obtained for the reaction 2A (g) + 2B (g) → C (g).
-1
-1
Trial
[A] (mol/L)
[B] (mol/L)
Rate (mol L hr )
1
3.00
0.50
2.25
2
3
4
5
6
3.00
3.00
1.00
2.00
3.00
1.00
1.50
2.00
2.00
2.00
4.50
6.75
1.00
4.00
9.00
Deduce, using the inspection method, the order of reaction with respect to A and B.
[4 marks]
b.
Write the experimentally verified rate law equation from this experimental data.
[1 mark]
c.
Calculate the value of the specific rate constant at the temperature at which these trials
were carried out.
[2 marks]
d.
Suggest one way to increase the overall rate of this reaction.
[1 mark]
11
24.
The solubility of calcium fluoride is 1.6 x 10-2 g/L at 20oC. Determine Ksp for calcium
fluoride.
[5 marks]
25.
Calculate the pH of a solution of hydrosulfuric acid, H2S, with an initial concentration of
0.500 mol/L. Ka for H2S is 9.5 x 10-8, and Ka for HS– is 1 x 10-19.
[5 marks]
12
Part D: Extended-response (C, I & MC, 19 marks, allow 25 minutes)
For the following questions, write the answer in the space provided. Use complete sentences in
your answers. If the answer requires mathematical calculations, show ALL of your work and the
required UNITS.
26.
Consider the equilibrium process shown below:
CO(g) + 2H2 (g) ↔ CH3OH (l) + 90 kJ
a.
Sketch an enthalpy change diagram for this reaction. Label the axes, reactants,
products, enthalpy change, and forward and reverse activation energies.
[4 marks]
b.
Predict the effect of the following changes on this equilibrium. Write favour reactants,
favour products or no change.
[4 marks]
i.
Increasing the pressure on the system
ii.
Lowering the temperature
iii.
Adding a very small amount of CH3OH (negligible volume change)
iv.
Removing CO (g)
13
c.
A catalyst is added to the reaction.
(i)
How does adding a catalyst affect the position of the equilibrium and the value of the
equilibrium constant?
[2 mark]
(ii)
What is the effect of adding a catalyst on the rate of CH3OH formation?
[3 marks]
27.
A sample of lactic acid is titrated with sodium hydroxide solution.
a.
Determine the pH of the resulting solution at the equivalence point if 35.0 mL sample of
lactic acid, C3H6O3, is titrated with 20.0 mL of a 4.0 x 10-4 mol/L sodium hydroxide
solution. Ka for lactic acid is 1.4 x 10-4.
[6 marks]
14
b.
Suggest an indicator that is suitable for this titration.
[1 mark]
c.
Sketch a fully labeled graph to represent this titration. On your diagram, indicate the
equivalence point.
[4 marks]
d.
Examine your titration curve. Briefly explain the region between the initial pH and just
before the equivalence point.
[3 mark]
15
16
17