1
Name : _________________________________ (
)
Class : __________
SMJK PEREMPUAN CHINA PULAU PINANG
CHEMISTRY FORM 5
PAPER 2
FINAL YEAR EXAM 2010
2 ½ HOURS
INSTRUCTIONS:
1. Read the questions carefully.
2. Answer all the questions in Section A.
3. Answer only ONE question in Section B.
4. Answer only ONE question in Section C.
Section
A
B
C
Question
1
2
3
4
5
6
7
8
9
10
Full marks
10
8
11
11
10
10
20
20
20
20
Marks
TOTAL
1
2
Section A [ 60 marks ]
1
Element X exists as a diatomic molecule at room temperature.
Diagram 1
When element X is dissolved in water, it forms a solution that turns blue litmus paper
red and then white.
(a)
At room temperature, element X exists as a volatile liquid.
(i) Describe the melting and boiling points of element X.
[1 mark]
_____________________________________________________________________
(ii) Give one reason for your answer in (a)(i).
[1 mark]
______________________________________________________________________
(b)
Predict the group where element X belongs in the Periodic Table of Elements. [1 mark]
______________________________________________________________________
(c)
(i) What are the properties of the solution obtained when element X is dissolved in
water ?
[2 marks]
_____________________________________________________________________
(ii)Write a chemical equation for the reaction that occurs when element X is dissolved
in water.
[1 mark]
_____________________________________________________________________
(d)
Element X also reacts with iron when heated to produce a compound with a formula
FeX3, according to the equation below :
3X2 (g) + 2Fe (s)  2FeX3 (s)
In an experiment, a student reacted 5.6g of iron powder with excess element X to
produce 29.6g of FeX3.
(i) Calculate the number of moles of iron that reacted in the experiment. [1 mark]
[Relative atomic mass : Fe=56]
2
3
(ii) Determine the relative atomic mass of element X.
2
(a)
[3 marks]
Diagram 2 shows the pH value of 4 solutions P,Q,R and S, which are of the same
concentration
Diagram 2
(i) Based on the above diagram, predict the dissociation of P in water.
[1 mark]
_____________________________________________________________________
(ii) Which of the solution has chemical properties which are similar to those of solution
P?
[1 mark]
_____________________________________________________________________
(b)
Which of the solutions contains the highest concentration of hydroxide ions ? [1 mark]
_____________________________________________________________________
(c)
(i) Name the reaction between solution P and solution S.
[1 mark]
____________________________________________________________________
(ii) Write an ionic equation for the reaction in (c)(i).
[1 mark]
______________________________________________________________________
(d)
(i) Which of the following solutions can R be ? Thick (√ ) the correct answer. [1 mark]
Sodium hydroxide
Sulphuric acid
Sodium nitrate
(ii) Give a reason for your answer in (d)(i).
[ 1 mark]
_____________________________________________________________________
(iii) Name two substances that can be used to produce the substance chosen in your
answer in (d)(i).
[1 mark]
_____________________________________________________________________
3
4
3
The flowchart in Diagram 3 shows how a sample of lead(II) sulphate is prepared from
lead(II) carbonate.
Lead(II) carbonate
solid
(a)
step 1
Lead(II) nitrate
solution
Step 2
Lead(II) sulphate
solid
(i) Describe how step 1 is carried out in the laboratory.
[2 marks]
_____________________________________________________________________
_____________________________________________________________________
(ii) Write a chemical equation for the reaction in (i).
[1 mark]
______________________________________________________________________
(iii) A little potassium iodide solution is added to some lead(II) nitrate solution. The
solution is then heated. What will be observed ?
[2 marks]
______________________________________________________________________
(b)
Lead(II) nitrate crystals are obtained from the lead (II) nitrate solution in step 1 by
crystallization. These crystals are then heated strongly in a test tube.
(i) Name the residue left in the test tube.
[1 mark]
______________________________________________________________________
(ii) What is the colour of the residue when it is hot and when it is cold?
[1 mark]
_____________________________________________________________________
(c)
(i) In step 2, sodium sulphate solution is added to lead(II) nitrate solution. State the
type of reaction that occurs.
[1 mark]
______________________________________________________________________
(ii) Write an ionic equation for the reaction.
[1 mark]
______________________________________________________________________
(d)
Can lead(II) sulphate be prepared by reacting lead(II) carbonate with sodium sulphate
solution ? Give a reason for your answer.
[2 marks]
_____________________________________________________________________
_____________________________________________________________________
4
5
4
Diagram 4 shows the energy level for two neutralization reactions.
Diagram 4
I: HCl (aq) + NaOH(aq) → NaCl(aq) + H2O(l)
II : CH3COOH (aq) + NaOH(aq) → CH3COONa(aq) + H2O(l)
(a)
(i) Define heat of neutralisation.
∆H = -57 kJmol-1
∆H = - 54 kJmol-1
[1 mark]
_____________________________________________________________________
_____________________________________________________________________
(ii) What is the difference between heat of neutralisation using hydrochloric acid and
sodium hydroxide solution and heat of neutralisation using ethanoic acid and sodium
hydroxide solution? Explain why.
[ 2 marks ]
_____________________________________________________________________
_____________________________________________________________________
(iii) If the sodium hydroxide solution in Reaction I is replaced with potassium
hydroxide solution, what will the heat of neutralization be? Explain your answer.
[2 marks]
_____________________________________________________________________
_____________________________________________________________________
(b)
In the experiment to determine the heat of neutralisation, 100cm3 of 0.5 moldm-3
ethanoic acid, CH3COOH and 100cm3 of 0.5 moldm-3 sodium hydroxide solution,
NaOH were measured into two plastic cups respectively . The initial temperatures of
both the ethanoic acid and sodium hydroxide solutions were recorded. Sodium
hydroxide solution was then poured into the plastic cup containing the ethanoic acid.
The mixture was stirred slowly and the highest temperature obtained was recorded.
Calculate
[Specific heat capacity of water = 4.2 Jg-1oC-1 , density of solution = 1.0g cm-3]
(i) The number of moles of water formed during the neutralisation process. [1 mark]
5
6
(c)
(ii) The change in heat energy during this neutralization process.
[1 mark]
(iii) The change in temperature during this experiment.
[1 mark]
In another experiment, 100cm3 of 2.0 moldm-3 ethanoic acid, CH3COOH and 100cm3
of 2.0 moldm-3 sodium hydroxide solution, NaOH were used. Predict the change in
temperature using these solutions. Explain why.
[ 3 marks ]
______________________________________________________________________
______________________________________________________________________
5
Diagram 5 shows the arrangement of the apparatus of an experiment which is set up to
study the effects of other metals on the rusting of iron. The two test tubes are left for 3
days. It is found that the colour of the agar-agar in test tube A has become pink while
the colour of the agar-agar in test tube B has become dark blue.
Diagram 5
(a)
(i) Write the chemical formula for the compound, potassium hexacyanoferrate(III).[1]
______________________________________________________________________
(ii) What is the aim of adding potassium hexacyanoferrate(III) solution into each test
tube.[1]
____________________________________________________________________
6
7
(b)
Name the particles which cause the change in the colour in
(i) test tube A : ___________________________________
(ii) test tube B : ___________________________________
(c)
[ 2 marks ]
Write the half equations for the following reactions :
(i) reduction in test tube A : ______________________________________
(ii) oxidation in test tube B : ______________________________________[2 marks ]
(d)
Name one metal which is suitable for replacing metal X in test tube A so that the
observation in test tube A is the same.
[ 1 mark ]
_____________________________________________________________________
(e)
Name one metal which is suitable for replacing metal Y in test tube B so that the
observation in test tube B is the same.
[ 1 mark ]
______________________________________________________________________
(f)
Arrange the three metals X, Y and iron according to their electropositivity in
descending order.
[ 1 mark]
______________________________________________________________________
(g)
What is the manipulated variable in this experiment ?
[ 1 mark ]
______________________________________________________________________
6
Table 1 below shows different conditions used in Experiment I and experiment II to
investigate the factors that affect the rate of reactions in three reactions.
Reaction Equation of reaction
A
2H2O2(aq)  2 H2O(l) + O2(g)
B
Zn(s) + H2SO4(aq) 
ZnSO4(aq) + H2 (g)
C
S2O32-(aq) + 2H+(aq) 
SO2(g) + S(s) + H2O(l)
Experiment I
50 cm3 1.0 mol dm-3
H2O2
Without copper(II)
sulphate solution
Room temperature
Experiment II
50 cm3 2.0 mol dm-3
H2O2
A few drops of
copper(II) sulphate
solution
40OC
Table 1
State the factors investigated in reaction
[ 3 marks]
(i) A :
___________________________________________________________________
(ii) B :
___________________________________________________________________
(iii) C :
___________________________________________________________________
7
8
(a)
State a suitable hypothesis for Experiment I and Experiment II in reaction C. [ 1 mark]
______________________________________________________________________
(b)
State all the constant variables in Experiment I and II in reaction C.
[ 2 marks]
_____________________________________________________________________
_____________________________________________________________________
(c)
Briefly describe the method used to measure the rate of reaction for reaction C. Hence,
predict the results of the measurement obtained in Experiment I and II in reaction C.
[ 2 marks]
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
(d)
Sketch the graphs of volume of gas collected against time taken for Experiment I and
Experiment II in reaction A on the same axes.
[2
marks]
Volume of gas(cm3)
Time taken (s)
8
9
Section B
[20 marks]
Answer any one question.
7
(a)
(i) What is a weak acid ?
Give an example of a weak acid.
[ 2 marks ]
(ii) Table 2 shows the pH value of two acids of the same concentration.
Acid
pH value
P
1
Q
4
Compare the pH values and the acidities of the two acids and give relevant
explanations.
[ 6 marks ]
(b)
Diagram 6 shows a reagent bottle containing sodium hydroxide solution. Part of the
label on the reagent bottle is torn and the concentration of the sodium hydroxide is
unknown.
Diagram 6
Describe an experiment that can be conducted to determine the exact concentration of
the sodium hydroxide solution. You are provided with all the apparatus needed and the
following chemicals:
Hydrochloric acid 0.5 moldm-3
Phenolphthalein
Your description should include the following aspects :
(i) The labelled diagram of the set-up of apparatus
(ii) Procedure of the experiment
(iii) Expected observation
(iv) Calculation to determine the concentration of the sodium hydroxide solution.
[12 marks]
8
(a)
The heat of combustion of heptane is -5512 kJ mol-1
(i) Define heat of combustion of heptane.
[ 1 mark ]
(ii) State two important informations that can be obtained from the statement given in
the box above .
[ 2 marks ]
9
10
(b)
A student sets up the apparatus below top determine the heat of combustion of heptane.
Diagram 7
The following are the results obtained from the experiment :
Volume of water in the beaker
= 250 cm3
Initial temperature of water
= 27.5oC
Highest temperature of water
= 69.5oC
Initial mass of spirit lamp and heptane = 48.3 g
Final mass of spirit lamp and heptane = 47.1 g
Density of water
= 1.0 gcm-3
Specific heat capacity of water
= 4.2 J g-1 oC-1
Relative molecular mass of heptane
= 100
(i) Using the above information , calculate the experimental value of heat of
combustion of heptane.
[ 5 marks ]
(ii) Compare the experimental value of heat of combustion and its theoretical value
Given. Give one reason for this.
[ 2 marks ]
(iii) Suggest three ways so that the experimental value of heat of combustion of
heptane would be closer to the theoretical value. Give an explanation to each of
your suggestions.
[ 6 marks ]
(c)
The heat of combustion of propan-1-ol is -2010 kJ mol-1
The information regarding the heat of combustion of propan-1-ol is shown above. Both
propan-1-ol and heptane can be used as fuel. By giving a suitable explanation, base on
their fuel value, which fuel, heptane or propan-1-ol, is a better fuel ?
Relative molecular mass of propan-1-ol
= 60
[ 4 marks ]
10
11
Section C
[20 marks]
Answer any one question.
9
(a)
(b)
(c)
Define oxidation and reduction in terms of changes in the oxidation number using a
chemical equation.
[2 marks]
Based on electrons transfer , explain the oxidation and reduction reaction in
(i) changing of Fe2+ ions to Fe3+ ions
(ii) changing of Fe3+ ions to Fe2+ ions
Use a suitable example for each of the reaction. Include half equations and overall
ionic equations in your answers.
[8 marks]
You are asked to locate the position of carbon in the reactivity series.
You are provided with chemicals such as carbon powder, magnesium oxide powder,
zinc oxide powder and copper(II) oxide powder.
Describe an experiment to locate the position of carbon in the reactivity series.
Your description must include the following :
The procedure of the experiment
The observation during the experiment
Chemical equations for the reaction that occur
Explanation on how to locate the position of carbon in the reactivity
series
[ 10 marks ]
10
(a)
With the help of a diagram, prove that how the type of electrodes used will influence
the products of an electrolysis. Your answer should include observations and half
equations.
[ 10 marks ]
(b)
Given are metal plates W, X, Y and Z and the aqueous nitrate solutions of their
respective salts. Describe an experiment to arrange these metals according to their
Electrochemical series. Your answer should include






Aim
Hypothesis
Materials
Set by :
Pn. Ch’ng Kuy Tze
Procedure
Tabulation of data
Conclusion
Verified by:
Pn. Aung Swee Ping
[ 10 marks ]
Approved by
Pn. Tay Yoke Chew
11