1. SPM2003
PAPER 2
Section A
[60 marks]
Answer all questions in this section.
The time suggested to complete Section A is 90 minutes.
1 Figure 1 shows the set-up of apparatus for an experiment to determine the empirical
formula of magnesium oxide.
FIGURE 1
Results:
Mass of crucible + lid = 24.0 g
Mass of crucible + lid + magnesium = 26.4 g
Mass of crucible + lid + magnesium oxide = 28.0 g
(a) What is meant by empirical formula?
……………………………………………………………………………….
[1 mark]
(b) Based on the above results,
(i) Calculate the mass of magnesium and the mass of oxygen that have
reacted.
[1 mark]
(ii) Calculate the mole ratio of magnesium atoms to oxygen atoms.
[Relative Atomic Mass: O, 16; Mg, 24]
[1 mark]
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2. SPM2003
PAPER 2
iii. determine the empirical formula of magnesium oxide
[1 mark]
(iv) write the chemical equation for the reaction in the experiment.
………………………………………………………………………
[1 mark]
(c) Why was the crucible lid opened once in a while during the experiment?
……………………………………………………………………………….
[1 mark]
(d) Metal X is placed below hydrogen in the reactivity series. You are required
to carry out an experiment to determine the empirical formula of the oxide
of metal X. The apparatus provided are combustion tube, glass tube, cork,
Bunsen burner, and porcelain dish.
(i) Draw a labeled diagram of the set-up of the apparatus for the
experiment.
[2 marks]
(ii) Describe the steps that should be taken to ensure that all the air in the
combustion tube has been expelled.
………………………………………….…………………………….
………………………………………….…………………………….
.……………………………………………………………………….
[3 marks]
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3. SPM2003
PAPER 2
2 Figure 2 shows part of the Periodic Table of Elements.
1 18
H 2 13 14 15 16 17
Mg 3 4 5 6 7 8 9 10 11 12
Fe
Figure 2
Based on Figure 2, answer the following questions.
(a) What is the element represented by the symbol Fe?
……………………………………………………………………………….
[1 mark]
(b) In Figure 2, mark ‘X’ in the boxes for all the transition elements.
[1 mark]
(c) State one specific characteristic of transition elements.
……………………………………………………………………………….
[1 mark]
(d) Write the electron configuration for the Mg atom.
……………………………………………………………………………….
[1 mark]
(e) (i) Write the chemical equation for the reaction between aluminium and
oxygen gas.
………………………………………….…………………………….
[1 mark]
(ii) Briefly state the electron transfer in the bond formation between
aluminium and oxygen.
………………………………………….…………………………….
………………………………………….…………………………….
[2marks]
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4. SPM2003
PAPER 2
Helium Gas Hydrogen gas
Light Light
Not reactive Flammable
colourless colourless
(f) Based on the above information, which gas is more suitable to be used in
meteorological balloons?
Give one reason.
……………………………………………………………………………….
[2 marks]
3 Figure 3 shows the flow chart for the industrial manufacture of sulphuric acid and the
production of fertilizer Z
Figure 3
Based on Figure 3, answer the following questions,
(a) Name the process of manufacturing sulphuric acid.
……………………………………………………………………………….
[1 mark]
(b) Name the substance X.
……………………………………………………………………………….
[1 mark]
(c) Substance X could react directly with water to form sulphuric acid. Explain
why this step is not carried out in the industrial process.
……………………………………………………………………………….
[1 mark]
(d) Write the chemical equation when oleum reacts with water to form sulphuric
acid.
……………………………………………………………………………….
[1 mark]
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5. SPM2003
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(e) Name the substance Y and the fertilizer Z.
Substance Y : …………………………………………………………………
Fertilizer Z : …………………………………………………………………
[2 marks]
The combustion of petrol in the engines of
vehicles produces sulphur dioxide. This gas
when dissolved in rain is corrosive.
(f) Write a chemical equation when sulphur dioxide reacts with water.
……………………………………………………………………………….
[1 mark]
4 Figure 4 shows the set-up of apparatus for the preparation of ethyl ethanoate from
the reaction of ethanol with ethanoic acid.
Figure 4
(a) On the Liebig condenser in Figure 4, mark "X' to indicate the place where
water flows in and Y where water flows out.
[1 mark]
(b) Why is the mixture heated using water bath?
……………………………………………………………………………….
……………………………………………………………………………….
[2 marks]
(c) (i) Name the reaction for the preparation of ethyl ethanoate.
………………………………………….…………………………….
[1 mark]
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6. SPM2003
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(ii) Write the chemical equation for the reaction in (c)(i).
………………………………………….…………………………….
[1 mark]
(d) The experiment is repeated by replacing ethanol with propanol
(i) Name the ester formed.
………………………………………….…………………………….
[1 mark]
(ii) State one physical property of the ester.
………………………………………….…………………………….
[1 mark]
(e) The flow chart below shows the conversion of ethanol to ethene and ethanol
to ethanoic acid.
Process I Process II
Ethene Ethanol Ethanoic Acid
Based on the flow chart, write the chemical equation for
(i) Process I. ………………………………………………………………
[1 mark]
(ii) Process II. ……………………………………………………………
[1 mark]
(f) An alkane has a structural formula as shown below.
What is the name of the alkane?
……………………………………………………………………………….
[1 mark]
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7. SPM2003
PAPER 2
5 Figure 5 shows the set-up of apparatus to investigate the reactions that take place in
test tubes P and Q.
FIGURE 5
(a) State the observation for the reaction
(i) in test tube P.
………………………………………….…………………………….
[1 mark]
(ii) in test tube Q.
………………………………………….…………………………….
[1 mark]
(b) Write the ionic equation for the reaction in (a)(i).
……………………………………………………………………………….
[1 mark]
(c) State what is meant by oxidizing agent in terms of electron transfer.
……………………………………………………………………………….
[1 mark]
(d) Referring to the reaction that takes place in test tube P.
(i) what is the change in the oxidation number of magnesium?
………………………………………….…………………………….
[1 mark]
(ii) name the oxidizing agent.
………………………………………….…………………………….
[1 mark]
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8. SPM2003
PAPER 2
(e) Referring to the reaction that takes place in test tube Q,
(i) state the type of reaction that occurs.
………………………………………….…………………………….
[1 mark]
(ii) state the oxidation number of bromine in bromine water.
………………………………………….…………………………….
[1 mark]
(iii) what is the function of bromine water?
………………………………………….…………………………….
[1 mark]
(iv) name another reagent that can replace bromine water.
………………………………………….…………………………….
[1 mark]
6 A student carried out an experiment to determine the heat of displacement for the
reaction between copper and silver nitrate solution. In this experiment, excess
copper powder was added to 100 cm 3 of silver nitrate solution 0.5 mol dm -3. The heat
of displacement in this experiment was - 05 kJ mol-3.
[Specific heat capacity of the solution is 4.2 J g-1 oC-1, and the density of the solution is 1
g cm -3]
(a) What is meant by heat of displacement?
……………………………………………………………………………….
[1 mark]
(b) Besides the data given above, state one other piece of data that is needed to
calculate the heat of displacement.
……………………………………………………………………………….
[1 mark]
(c) State one precaution that must be taken while carrying out the experiment.
……………………………………………………………………………….
[1 mark]
(d) (i) State one observation of the experiment.
………………………………………….…………………………….
[1 mark]
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9. SPM2003
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(ii) State the reason for the observation in (d)(i).
………………………………………….…………………………….
[1 mark]
(e) Based on the information from this experiment, calculate
(i) the number of moles of silver ions reacted.
[1 mark]
(ii) the amount of heat released.
[1 mark]
(iii) the change in temperature.
[1 mark]
(f) Draw an energy level diagram for the reaction in this experiment.
[2 marks]
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10. SPM2003
PAPER 2
(g) The experiment is repeated using 100 cm3 of 1.0 mol dm-3 silver nitrate solution
and excess copper powder.
Calculate the temperature change in this experiment.
Explain why this change of temperature is different from that in (e)(iii).
……………………………………………………………………………….
……………………………………………………………………………….
[3 marks]
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11. SPM2003
PAPER 2
Section B
[20 marks]
Answer any one question from this section.
The time suggested to complete Section B is 30 minutes.
1 The rate of reaction is affected by several factors. One of the factors is the size of
particles.
One kilogramme of meat, cut into big pieces, takes a
longer time to cook compared to one kilogramme of
meat cut into small pieces
(a) Explain the above statement based on the size of the particles. [2 marks]
(b) A student carried out three experiments to investigate the effects of the factors
influencing the rate of reaction. Table I shows the results of the experiments.
Experiment I II III
Set up of
apparatus
Temperature
30 40 50
/oC
Time taken
for all
magnesium 50 20 15
to dissolve
/sec
Table 1
(i) Write the chemical equation for the reaction between magnesium and
hydrochloric acid. Calculate the maximum volume of hydrogen gas
produced.
[Relative atomic mass: Mg, 24; molar gas volume: 24 dm 3 mol-1 at
room condition] [4 marks]
(ii) Sketch the graphs for the volume of hydrogen gas against time for
Experiment I, II,and III on the same axes. [3 marks]
(iii) Calculate the average rate of reaction for Experiment I, II, and III in
cm3 s-1 [3 marks]
(iv) Compare the rates of reaction between Experiment I and Experiment II,
and between Experiment II and Experiment III.
With reference to collision theory, explain why there are differences
in the rates of reaction in the experiments. [8 marks]
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12. SPM2003
PAPER 2
2 (a) State two methods of food preservation which are used in our daily lives and
explain how the methods work. [4 marks]
(b) A student discovered that his socks have oily stains. He washed them with
soap.
Explain the cleansing action of soap on the oily stains. [8 marks]
(c) A student carried out four experiments to investigate the cleansing effects of
soap and detergent on oily stains in soft water and hard water.
Table 2 shows the set-up of apparatus, types of water used, and the
observations for Experiments I, II, III, and IV.
Experiment I II III IV
Set up of
apparatus
Oily stains Oily stains Oily stains Oily stains
observation
disappeared remains disappeared disappeared
Table 2
Compare the cleansing effects between (i) Experiments I and II (ii)
Experiments II and IV
Explain why there are differences in the observations: State the
substance which is more
suitable as a cleansing agent to remove oily stains. [8 marks]
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13. SPM2003
PAPER 2
Section C
[20 marks]
Answer any one question from this section.
The time suggested to complete Section C is 30 minutes.
3 (a) Lime juice was electrolysed using carbon electrodes.
What is produced at the cathode? Write a half-equation for the reaction.
[2 marks]
(b) Figure 6 shows two types of cell.
Figure 6
Compare and contrast cell P and cell Q. Include in your answer the
observation and half- equations for the reactions of the electrodes in both
cells. [8 marks]
(c) A student intends to electroplate an iron key with a suitable metal to
beautify it. Design a laboratory experiment to electroplate the iron key.
Your answer should consist of the following:
• Chemicals required
• Procedures of the experiment
• Diagram showing the set-up of apparatus
• Chemical equation involved in the reaction
• Observation
[10 marks]
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14. SPM2003
PAPER 2
4 (a) A farmer discovered that his vegetables were not growing well because the
soil was poor and acidic. As a chemistry student, you can help the farmer.
Suggest how the farmer can overcome the problem. [2marks]
(b) Figure 7 shows an incomplete flow chart of cation and anion tests for salt
X.
Use the reagents listed below and complete the flow chart to confirm that
salt X contains Pb2+ ions and C032- ions. Include your observations.
REAGENTS
Dilute hydrochloric acid, dilute
nitric acid, and lime water
[8 marks]
(c) You are required to prepare dry magnesium chloride salt. The chemicals
supplied are
• magnesium sulphate solutions,
• dilute hydrochloric acid,
• potasium carbonate solution.
Describe a laboratory experiment to prepare the salt. In your description,
include the chemical equations involved. [10 marks]
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