1202 Question Bank Chemistry Form 4 KSSM

©PAN ASIA PUBLICATIONS

Contents








MUST KNOW iii – x
Chapter 1 Introduction to Chemistry 1 – 9
NOTES 1
Paper 1 3
Paper 2 6
©PAN ASIA PUBLICATIONS
Paper 3 9
Chapter 2 Matter and the Atomic Structure 10 – 25
NOTES 10
Paper 1 12
Paper 2 19
Paper 3 25

Chapter 3 The Mole Concept, Chemical Formula and Equation 26 – 39
NOTES 26
Paper 1 27
Paper 2 33
Paper 3 39

Chapter 4 The Periodic Table of Elements 40 – 53
NOTES 41
Paper 1 42
Paper 2 48
Paper 3 53

Chapter 5 Chemical Bond 54 – 68
NOTES 54
Paper 1 56
Paper 2 61
Paper 3 68

Chapter 6 Acid, Base and Salt 69 – 88
NOTES 69
Paper 1 75
Paper 2 81
Paper 3 87

Chapter 7 Rate of Reaction 89 – 107
NOTES 89
Paper 1 91
Paper 2 100
Paper 3 107

Chapter 8 Manufactured Substances in Industry 108 – 125
NOTES 108
Paper 1 113
Paper 2 119
Paper 3 125


Answers 126 – 142




ii

MUST


KNOW Mnemonics







Acid, Base and Salt Acid, Base and Salt
• White precipitate in sodium hydroxide solution are
ZAP MgCa (Pronounced as “ZAP MeCa”)
Add a little sodium hydroxide solution
©PAN ASIA PUBLICATIONS
BLUE RED sister loves SOUR plum No precipitate White precipitate formed

NH + ZAP MgCa
4
Zn Al Pb 2+ Mg Ca 2+
2+
3+
2+
BLUE litmus paper turns RED (Acid) Heat up and test with Add excess sodium
red litmus paper
hydroxide solution
NH + Precipitate Precipitate does
4 dissolves not dissolve
ZAP MgCa
2+
3+
2+
Zn Al Pb 2+ Mg Ca 2+
Mnemonics (Chapter 6) 1 @ Pan Asia Publications Sdn. Bhd. Mnemonics (Chapter 6) 7 @ Pan Asia Publications Sdn. Bhd.
Acid, Base and Salt Acid, Base and Salt
• Soluble salt, NO SPA • White precipitate in ammonia solution are Zn MgPA
Sodium Ammonium (Pronounced as “Zinc Mengapa”)
Add a little ammonia solution
NO 3 – NO SPA No precipitate White precipitate formed

Potassium NH , Ca 2+ Zn MgPA
+
4
2+
2+
2+
3+
3+
• Insoluble salt Zn Al Mg Pb Al
PBC – Sulphate HPA – Chloride Add excess ammonia
P ← PbSO 4 H ← Hg Cl 2 solution and shake evenly
2
B ← BaSO 4 P ← PbCl 2 Precipitate Precipitate does
C ← CaSO A ← AgCl dissolves not dissolve
4
Zn MgPA
2+
3+
2+
Zn 2+ Mg Pb Al
Mnemonics (Chapter 6) 3 @ Pan Asia Publications Sdn. Bhd. Mnemonics (Chapter 6) 9 @ Pan Asia Publications Sdn. Bhd.
Acid, Base and Salt Manufactured Substances in Industry
• “Angcle Basuh Ferrari dgn Susu Pekat Nestle”
(Pronouced as Bronchus) (Pronouced as Zip cobra)
Bron Cu Sn Zip Cu bra
Any acid HNO HNO H SO
3 3 2 4
AgNO 3 Ang Ba(NO) 3 Ba Fe SO 4 Ferrari Bronze Copper Tin Zinc Copper Brass
2
Susu
H SO pekat pekat
2
4
(Pronouced as Steel IC)
Steel I C
CO 2– Cl – Cle SO 2– suh NO – Nestle
3 4 3
Steel Iron Carbon

Mnemonics (Chapter 6) 5 @ Pan Asia Publications Sdn. Bhd. Mnemonics (Chapter 8) 11 @ Pan Asia Publications Sdn. Bhd.

MUST


KNOW Important Facts







Matter and the Atomic Structure Acid, Base and Salt
Electron • Only the sulphate salts below decompose when heated.
Symbol: e – Proton FeSO → Fe O + SO + SO
3
2
4
Relative charge: –1 Symbol: p ZnSO → ZnO + SO 2 3
4
Valence©PAN ASIA PUBLICATIONS
1 Relative charge: +1 CuSO → CuO + SO 3
Relative mass: 4 3
1 840 Relative mass: 1 (NH ) SO → 2NH + H SO
4
2
3
4 2 4 Ammonia gas Sulphuric acid vapour
• All chloride salts ARE NOT decomposed by heat, except
ammonium chloride.
NH Cl → NH + HCl
4
3
Ammonia Hydrogen
gas chloride gas
Neutron • Most metal carbonates decompose to form metal oxides and
Symbol: n carbon dioxide gas when heated.
Relative charge: 0 (neutral) • However, potassium carbonate and sodium carbonate ARE
Relative mass: 1 NOT decomposed by heat.
Important Facts (Chapter 2) 13 @ Pan Asia Publications Sdn. Bhd. Important Facts (Chapter 6) 19 @ Pan Asia Publications Sdn. Bhd.
The Mole Concept, Chemical Formula and Equation Rate of Reaction
• Diagram shows the relationship between number of moles, • Collision Theory.
mass of substance, number of particles and volume of gas. • Factors affecting the rate of reaction
× Molar mass ÷ N ❖ Size of reactant
A ❖ Concentration
❖ Temperature
Number of Number of particles: ❖ Catalyst
Mass
moles, n atom, molecules, ions
• When frequency of collision between particles increases,
frequency of effective collision between particles increases.
÷ Molar mass ÷ N A This causes the rate of reaction to increase.

÷ Molar volume × Molar volume

Volume of gas


Important Facts (Chapter 3) 15 @ Pan Asia Publications Sdn. Bhd. Important Facts (Chapter 7) 21 @ Pan Asia Publications Sdn. Bhd.

Chemical Bond Manufactured Substances in Industry

• Metallic bond Type of alloy Composition
Duralumin • Aluminium, 93%, • Magnesium, 3%
• Copper, 3% • Manganese, 1%
Bronze • Copper, 90% • Tin, 10%
+ + + + + + + + + + Positively
electron + + + + + + + + + + charged Brass • Copper, 70% • Zinc, 30%
metal ion
+ + + + + + + + + +
+ + + + + + + + + + Steel • Iron, 99% • Carbon, 1%
+ + + + + + + + + +
Delocalised electrons Stainless steel • Iron,73% • Chromium, 18%
from “sea of electrons”
• Nickel, 8% • Carbon, 1%
Pewter • Tin, 95% • Antimony, 3.5%
• Copper, 1.5%
Important Facts (Chapter 5) 17 @ Pan Asia Publications Sdn. Bhd. Important Facts (Chapter 8) 23 @ Pan Asia Publications Sdn. Bhd.

MUST


KNOW Important Diagrams







Matter and the Atomic Structure Rate of Reaction
• Graph of temperature against time for the heating of
naphthalene is shown below. Exothermic reaction
Energy
©PAN ASIA PUBLICATIONS
Temperature (°C)
D
Without catalyst

B C E a
80°C With catalyst
E '
a
Reactants
A
Products
Time (min)
Reaction pathway
Important Diagrams (Chapter 2) 25 @ Pan Asia Publications Sdn. Bhd. Important Diagrams (Chapter 7) 31 @ Pan Asia Publications Sdn. Bhd.


Matter and the Atomic Structure Rate of Reaction

• Graph of temperature against time for the cooling of
naphthalene is shown below. Endothermic reaction

Energy
Temperature (°C)
Without catalyst
P
With catalyst
Q R E
80°C a
E ' Products
a
S
Reactants
Time (min)
Reaction pathway
Important Diagrams (Chapter 2) 27 @ Pan Asia Publications Sdn. Bhd. Important Diagrams (Chapter 7) 33 @ Pan Asia Publications Sdn. Bhd.

Acid, Base and Salt Rate of Reaction

• Correct orientation
• Total energy greater
H Cl H Cl H Cl ● Correct orientation
than or
● Total energy greater than or
equal to the activation energy
equal to the
H Cl H Cl H Cl
activation energy
● Effective collision occurs
Collide Bond breaking and
bond formation • Effective collision
More acidic Neutral More alkaline occurs
• Wrong orientation
Cl Cl ● Wrong orientation
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 • Total energy greater than
● Total energy greater than or
H H H H or equal to the activation
Cl Cl equal to the activation energy
energy
● Ineffective collision occurs
Collide Bounce • Ineffective collision
pH stands for 'hydrogen potenz' (hydrogen power) off occurs
● Correct orientation
H Cl H Cl • Correct orientation
• Total energy less than
● Total energy less than
the activation energy
H Cl H Cl the activation energy
● Ineffective collision occurs
• Ineffective collision
Collide Bounce
off occurs
Important Diagrams (Chapter 6) 29 @ Pan Asia Publications Sdn. Bhd. Important Diagrams (Chapter 7) 35 @ Pan Asia Publications Sdn. Bhd.

1
Chapter Introduction To Chemistry





NOTES


1.1 Development in Chemistry Field Nutritionist Study the
and Its Importance in Daily Life nutritional value
©PAN ASIA PUBLICATIONS
of food
1. The word 'chemistry' is believed to be originated
from the Arabic word 'Al-kimiya'. Cosmetology Cosmetic chemist Formulates skin
2. Chemistry is defined as one of the fields of science care, personal
that studies the structures, properties, compositions care and colour
and interactions between matters. cosmetics for
3. The table below shows various chemicals commonly manufacturers.
used in agriculture, industry, food and medicine. Pharmaceutical Pharmacist Study medicine,
drugs and their
Food Preservative effects
Colouring
Flavouring 1.2 Scientific Investigation in
Agriculture Pesticide Chemistry
Herbicide 1. Scientific investigation is a systematic scientific
Fertiliser method used to solve science related problems.
Medicine Analgesic 2. Steps involved in a scientific method:
Antibiotic
Antiseptic Making
Industry Polymer observation
Glass
Ceramic
Alloy Making Writing
inference report
4. Researches in various chemistry fields have been
carried out every day.
5. The need for chemical technology to solve problems Identifying Making
spurs the development of chemical technology. problem conclusion
6. The following table shows careers that require
knowledge in chemistry.
Making Interpreting
Field Career Job scope hypothesis data
Biotechnology Biochemist Study the chemical
processes in living
things Identifying Collecting
Nanotechnology Nanotechnology Learn new things variables data
engineer that can change
the health, science,
technology, and the Controlling Planning
environment on a variables experiment
molecular level
Nutrition Dietitian Expert in human 1.3 Usage, Management and
nutrition who Handling Of Apparatus and
alters patients' Materials
diet based on their
medical conditions 1. The laboratory is an important place to study
and individual chemistry. However, this place can become dangerous
needs if we do not obey the laboratory rules and practise the
safety measures.

1

PAPER 1

Each question has four different answers, A, B, C and D. For each question, choose one answer only.

1.1 Development in Chemistry Field Based on the statement above, what is his career?
and Its Importance in Daily Life A Nanotechnology engineer C Nutritionist
B Food scientist D Dietitian
1. The word ‘Chemistry’ is believed to be originated
from 1.2 Scientific Investigation in
A Latin word C Arabic word Chemistry
B Malay word D English word
©PAN ASIA PUBLICATIONS
9. Which of the following is the first step in a scientific
2. Which of the following statements is true about method?
Chemistry? A Identifying problem C Making hypothesis
A Chemistry studies all matters in the Earth’s crust. B Making observation D Making inference
B Chemistry is the study of the structure of living
things. 10. Which step in a scientific method is used to verify if
C Chemistry relates the matters that make up the the inference is true or false?
universe. A Planning an experiment
D Chemistry is the study of structures, properties, B Controlling variables
compositions, and interactions between matters. C Making observation
D Making hypothesis
3. Which of the following is not an example of
chemicals? 11. Mei Yu is giving an explanation about the event she
A Fibre C Energy has observed based on her past experience. Which
B Balloon D Liquefied gas step in a scientific method is she applying?
A Making inference
4. Which substance is used to kill weeds? B Identifying problem
A Fungicide C Pesticide C Making hypothesis
B Herbicide D Carbide D Identifying variables

5. Which of the following chemicals is used to prevent 12. Which of the following is the early logical conclusion?
the oxidation of food? A Inference C Hypothesis
A Stabiliser C Preservative B Conclusion D Data interpretation
B Thickener D Antioxidant
13. How to test if the hypothesis made is correct?
6. Sodium nitrite is added to burger so that the burger A Carrying out experiment C Collecting data
meat can last longer. What is the function of sodium B Planning an experiment D Interpreting data
nitrite?
A Flavouring C Colouring 14. What is a manipulated variable?
B Preservative D Stabiliser A Factor that changes accordingly
B Factor that remains the same in the experiment
7. Which of the following requires the knowledge of C Factor that can be measured with measuring
chemistry? instruments
A Lawyer C Carpenter D Factor that is purposely changed to see the effect of
B Pharmacist D Plumber other variables

8. The following statement refers to a type of occupation. 15. To relate a manipulated variable and a responding
variable in order to explain the question that has been
He studies and determines the nutrient levels asked is a step to
of food by analysing their contents. He also A collect data
finds the best way to distribute, process, B interpret data
preserve and package food. C make a conclusion
D construct a hypothesis
3
Question 3: Question 10:
Chemical is a matter. It must have mass and occupies space. Based on observation, an inference (early conclusion) can be made to
explain the observation. To verify the explanation of the observation, SOS TIP
a hypothesis is constructed. Experiment is carried out to test if the
3 hypothesis made is accepted or rejected. 3

52. Phosphorus-31 and phosphorus-32 are isotopes. 54. A food technologist intends to destroy bacteria
SPM
SPM Which statement is correct? HOTS Applying SPM by treating the food with radiation. Which of the
SPM
CLONE CLONE
[Proton number of phosphorus = 15] following is suitable to be used?
A Phosphorus-31 has 15 protons and 16 electrons A Lead-210 C Carbon-14
B Phosphorus-32 has 15 electrons and B Cobalt-60 D Hydrogen-3
17 neutrons
C Phosphorus-31 has a smaller number of electrons 55. Diagram 23 shows a person suffering from a disease.
than phosphorus-32 SPM
SPM
D Phosphorus-31 has the same number of neutrons as CLONE
phosphorus-32
©PAN ASIA PUBLICATIONS
53. Diagram 22 shows the symbol used to label the food
SPM
SPM that is irradiated with isotope Q.
CLONE

Diagram 23
Which of the following is suitable to treat the disease?
A Cobalt-60
Diagram 22 B Iodine-131
What is isotope Q? C Sodium-24
A carbon-14 C phosphorus-32 D Magnesium-24
B sodium-24 D cobalt-60





PAPER 2

Section A
Answer all questions.

1. Water has the formula of H O. Diagram 1 shows the arrangement of water particles in three states of matter X, Y and
2
SPM Z.
SPM
CLONE








X Y Z
Diagram 1
(a) What are the physical states labelled X, Y, and Z? [3 marks]
X : Y : Z :

(b) What type of particle is found in water? [1 mark]



(c) State the melting point of pure water. [1 mark]



19
Question 55: Question 1:
Cobalt-60 is usually used to treat cancer but iodine-131 is specifically used to (b) Types of particles refer to atom, molecule or ion.
thyroid cancer. (c) Melting point = freezing point. Freezing point of pure water is 0ºC SOS TIP
and boiling point of pure water is 100ºC.
19 19

PAPER 3


You have to determine the melting point of a given substance T in a plastic pack.
Using the apparatus supplied, carry out an experiment to determine the melting point of the substance T.

The following are the brief steps of experiment:
1. Heat the substance T until the temperature reaches 70 °C.
2. Start the stopwatch instantly.
3. Record the temperature of substance T at 30-second intervals until the temperature reaches 90 °C.
(a) Record the thermometer readings. [3 marks]
©PAN ASIA PUBLICATIONS
(b) Plot a graph of temperature against time in a graph paper. [5 marks]
(c) Based on the graph plotted, mark and label the melting point substance T. [3 marks]
(d) Explain why the temperature of substance T remains the same for a period of time. [2 marks]
(e) State the physical state(s) of substance T during [3 marks]
(i) 0 s
(ii) 90 s
(iii) 210 s

Note:
If you are not able to carry out the experiment as described above, observe the thermometer readings and record the
temperature in the space provided. Then, answer the question using the data you have recorded.


Time Thermometer reading Temperature (°C) Time Thermometer reading Temperature (°C)
(s) (s)


70 80
0 (i) 120 (v)

60 70




80 80
30 (ii) 150 (vi)
70 70




80 90
60 (iii) 180 (vii)
70 80




80 90
90 (iv) 210 (viii)
70 80





25
Question 3:
(a) When recording the thermometer reading, consider the accuracy of the (c) Make sure you draw the dotted line to indicate how you determine
thermometer by putting the correct decimal place. Do not put unit as the the melting point. SOS TIP
unit is on the heading of the table.
25

3 The Mole Concept, Chemical
Chapter Formula and Equation





NOTES


3.1 Relative Atomic Mass and 2. Avogadro constant, N is defined as the number of
A
Relative Molecular Mass particles in one mole of a substance. In other words,
©PAN ASIA PUBLICATIONS
1 mol of substance contains 6.02 × 10 particles that
23
1. The mass of an atom when compared to a standard form the substance.
atom is called relative atomic mass, RAM. Relative 3. When we say, 2 pairs of shoes, it means 2 × 2 = 4
atomic mass has no unit because it is not the actual shoes. If we were to say 2 dozen of shoes, that means
mass but only a comparison value. 2 × 12 = 24 shoes.
4. What if we say 2 moles of shoes? It means 2 × 6.02 ×
Standard atom Why is it chosen 10 = 1.204 × 10 shoes.
23
23
Carbon-12 • Carbon-12 was used as the × N
The mass of one reference standard in mass A
carbon-12 atom spectrometers. Number of
was assigned • Most elements combine with Number of particles Number of moles, n
12 units. carbon-12. moles, n Atom // = Number of particles
• Exists as a solid at room molecule // N A
temperature and easy ion
to handle. ÷ N
A
2. Based on the carbon-12 scale, the relative atomic 5. The molar mass is the mass of one mole of the
mass of an element is the average mass of one atom substance.
1 23
of the element when compared with 12 of the mass 6. The molar mass of a substance contains 6.02 × 10
of one carbon-12 atom. particles of the substance.
7. The unit of molar mass is g mol .
–1
Relative atomic mass (RAM)
Average mass of one atom of the element × molar mass
= 1 Number of moles, n
× Mass of one carbon – 12 atom Number of
12 Mass Mass
moles, n = Molar mass
3. Relative molecular mass of a molecule is defined as ÷ molar mass
the average mass of the molecule when compared
1
with of the mass of one carbon-12 atom. 8. The molar volume of a gas is the volume occupied
12 by one mole of the gas or 6.02 × 10 particles
23
Relative molecular mass (RMM) of the gas.
–1
3
Average mass of one molecule 9. The unit of molar volume is dm mol .
= 1 10. Under the same temperature and pressure, an equal
× Mass of one carbon – 12 atom number of moles of any gas will have the same
12
volume.
4. The term ‘relative molecular mass’ can only be used 11. The molar volume depends on the conditions.
for substances that are made up of molecules.
For ionic compounds, the ‘relative formula mass Molar volume
(RFM) is used instead. Standard temperature and Room conditions:
pressure, STP: Temperature = 25 °C
3.2 Mole Concept Temperature = 0 °C Pressure =1 atm
1. One mole, with the symbol ‘mol’ of substance is Pressure = 1 atm
defined as: 22.4 dm mol –1 24 dm mol –1
3
3
Substance that contains 6.02214076 × 10 23 22400 cm mol –1 24 000 cm mol –1
3
3
elementary entities of the substance.

26

Molecular formula = (Empirical formula)
× molar volume n
Number of moles, n
Number of Volume Volume n × empirical formula = molar mass
moles, n = Molar volume 4.
÷ molar volume Formula that shows the
Empirical simplest whole number
3.3 Chemical Formula formula ratio of atoms of each
element in a compound
1. Chemical formula is a representation of a chemical Chemical
substance using letters to represent the atoms and formulae Formula that shows
©PAN ASIA PUBLICATIONS
subscript numbers to show the numbers of each the actual number of
type of atoms found in the elementary entities of Molecular atoms of each element
the substance. formula in the molecule of a
2. From the chemical formula, we know: compound

Water is made up of hydrogen and oxygen 3.4 Chemical Equation
H O Relative molecular mass
2 = 2(1) + 16 1. A chemical equation is a precise description of a
chemical reaction.
2 hydrogen 1 oxygen = 18 2. Chemical equation gives us:
Ratio of hydrogen to oxygen
atoms atom
= 2 : 1 (a) Qualitative information – Tell us the reactants
and products involved in the reaction and the
3. Molecular formula can only be determined if we physical states of the reactants and products.
know the empirical formula and molar mass OR (b) Quantitative information – Tells us the exact
relative molecular mass of that substance. proportions (number of moles) of reactants and
products in the reaction.



PAPER 1

Each question has four different answers, A, B, C and D. For each question, choose one answer only.


3.1 Relative Atomic Mass and Relative
Molecular Mass CO 2 C H 10 O 2 N 2
4
1. Why was carbon-12 chosen as the standard atom to
SPM
SPM determine the relative atomic mass of other elements?
13
A Carbon has three isotopes. W X Y Z
B Carbon is a solid and easier to be handled. Diagram 1
C Carbon is heavier than oxygen and hydrogen.
D Carbon is located in Group 14 in the Periodic Table Which balloon becomes the smallest after one day?
of Elements. HOTS Applying
[Relative atomic mass: H = 1, C = 12, N = 14,
2. A compound with formula X CO has a relative O = 16]
2
3
SPM
SPM formula mass of 138. What is the relative atomic A W C Y
CLONE B X D Z
mass of X? HOTS Applying
[Relative atomic mass: C=12, O=16]
A 39 C 78 4. The chemical formula for potassium
SPM
B 69 D 110 SPM hexacyanoferrate(II) is K Fe(CN) . What is its relative
4
6
CLONE
formula mass? HOTS Applying
3. Ahmad filled four different types of gases into four [Relative atomic mass: C = 12, N = 14, K = 39, Fe = 56]
SPM balloons as shown in Diagram 1. A 121 C 238
SPM
CLONE B 199 D 368
27
Question 3:
The smaller the size of particles, the easier the particles to penetrate through the semipermeable membrane. Therefore, the size of balloon will be reduced. SOS TIP
27 27

PAPER 2

Section A
Answer all questions.

1. (a) (i) What is the chemical formula of ammonia molecule? [1 mark]
SPM
SPM

CLONE
(ii) What is the name of the isotope of the element that is used as the standard to determine the relative atomic
mass of other elements? [1 mark]


(b) (i) What is the mass of 6.0 dm of ammonia gas, NH at room conditions? [2 marks]
3
3
HOTS Applying
[1 mol of gas occupies 24 dm at room conditions; molar mass of NH = 17 g mol ]
–1
3
3





(ii) How many molecules are there in 6.0 dm of ammonia gas? HOTS Applying [1 mark]
3
[Avogadro’s constant = 6.02 × 10 ]
23







(iii) Explain briefly the relationship between the volume, mass and the number of molecules of ammonia in 1(b)
©PAN ASIA PUBLICATIONS
(i) and 1(b)(ii) at room conditions. [3 marks]




2. Atom is very small and it is impossible to weigh the mass of an atom using any electronic balance. Thus, chemist
SPM
SPM compares the mass of an atom with a standard atom. The mass obtained through comparison is called relative atomic
CLONE 1
mass. Diagram 1 shows the comparison of mass of lithium atom with 12 of carbon-12 atom.
1
12 of a carbon-12 atom
Li C-12

1
12 of a carbon-12 atom

Diagram 1
(a) What is the meaning of relative atomic mass? [1 mark]



33
Question 1:
(b) (i) (b) (iii) When explaining the relationship,
Mass(g) relate the volume, mass and number
× Molar mass ÷ Molar mass of molecules to the number of moles. SOS TIP
× N A × Molar volume
33
Number of particles Number of moles Volume of gas 33
÷ N A ÷ Molar volume

Section B

7. (a) The following chemical equation shows the burning of carbon.
SPM
SPM
CLONE
2C(s) + O (g) → 2CO(g)
2
Based on the equation, give two qualitative information and one quantitative information. [3 marks]
(b) A hydrocarbon X, consists of 82.75 % of carbon and 17.25 % of hydrogen by mass. The relative molecular mass
of X is 58.
(i) Determine the empirical formula of hydrocarbon X. [4 marks]
(ii) What is the molecular formula of hydrocarbon X. [2 marks]
©PAN ASIA PUBLICATIONS
(c) A good fertiliser will have a higher percentage of nitrogen by mass. Below are two types of fertilisers.

Urea, CO(NH ) (NH ) PO 4
2 2
4 3
Compare the percentage of nitrogen by mass for these fertilisers. Then, identify and explain which fertiliser is a
better fertiliser. HOTS Applying [6 marks]
[Relative atomic mass: H = 1, C = 12, N = 14, O = 16, P = 31]


Section C

8. (a) The relative atomic mass of an atom of element is compared with the standard atom. HOTS Applying
Using the idea above, find the
(i) number of times 2 bromine atoms are heavier compared to 5 oxygen atoms.
[Relative atomic mass: O = 16; Br = 80;]
(ii) number of carbon atoms that have the same mass as 2 krypton atoms.
[Relative atomic mass: C = 12; Kr = 84] [4 marks]
(b) Diagram 5 shows two methods used in the laboratory to determine the empirical formula of a compound.
Method I Method II


Lid
Chemical substance
Magnesium
ribbon Dry hydrogen
Crucible gas


Heat
Heat

Diagram 5
Compare these two methods with reference to the following aspects: HOTS Creating
• Method used to determine the empirical formula of the metal oxide
• Changes in the initial mass of the reactant and final mass of the product
• Why there are changes in the mass of the reactant and the mass of the product? [6 marks]

(c) Statement below is about metal Y.
Metal Y is located higher than hydrogen in the reactivity series.

Describe an experiment to determine the empirical formula of oxide of metal Y. HOTS Creating
Your answer should include the procedure of experiment and calculation of the empirical formula.




38 Question 7:
SOS TIP (c) Make sure you use the superlative adjective to explain the (b) Refer to reactivity series to determine which method to be used to determine
the empirical formula.
comparison.
(c) Only use unknown in the calculation. You are not required to create any
Question 8:
38 (a) Consider the formula data.
Number of atom P × RAM of atom P = number of times heavier ×
(number of atom Q × RAM of atom Q)

PAPER 3


You are required to determine the empirical formula of magnesium oxide. Referring to the Diagram 1, carry out the
relevant experiment.

The crucible and lid are The crucible, lid and The magnesium ribbon The crucible, lid and
weighed. magnesium ribbon are is heated until it reacts magnesium oxide formed
weighed. completely with oxygen. are weighed when cooled.

©PAN ASIA PUBLICATIONS

Lid
Magnesium
Crucible ribbon White
Magnesium powder
ON Digital ON ON
OFF OFF OFF
balance Heat
Diagram 1

(a) State two observations that can be obtained for the experiment. [2 marks]
(b) State the corresponding inferences based on the observations in (a). [2 marks]
(c) Record the reading to two decimal places for [3 marks]
(i) Mass of crucible with lid: ...............g
(ii) Mass of crucible with lid and magnesium ribbon: ...............g
(iii) Mass of crucible with lid and magnesium oxide when cooled: ...............g
(d) What is the mass of the magnesium and mass of oxygen used in the reaction? [3 marks]
(e) Determine the empirical formula of magnesium oxide. [3 marks]
[Relative atomic mass of Mg = 24; O = 16]
(f) Referring to the answer in (e), determine the number of moles of magnesium that reacts with 2 moles of oxygen
atoms. [3 marks]

Note:
If you are not able to carry out the experiment as described above, you can answer this question using the following
samples of data:



Mass of crucible with lid Mass of crucible with lid and Mass of crucible with lid and
magnesium ribbon magnesium oxide when cooled

Lid
Magnesium
Crucible ribbon White
powder
ON 38.4972 g Digital ON ON
OFF OFF 39.2210 g OFF 39.7025 g
balance











39
Question (a): Question (b):
The observation does not include the change in the figure in electronic balance. Inference is the early conclusion of the observation. It is actually the
logical reason why an observation or phenomenon occurs. SOS TIP


39

5 Chemical Bonds
Chapter





NOTES


5.1 Basics of Compound Formation 5. There are 3 types of covalent bonds:

©PAN ASIA PUBLICATIONS
1. Most elements will combine with one another to form Number of
compounds. shared pair of Example
2. Why should elements form compounds? Because electrons
compounds are more stable than free elements. The
formation of compounds results in the formation of X X Y or X Y
chemical bonds. 1
3. In the formation of chemical bonds, each atom will Single covalent bond
change its electron arrangement to achieve a stable
electron arrangement through:
(a) transfer of electrons X X Y or X Y
X
(b) sharing of electrons 2
Double covalent bond
5.2 Ionic Bond

X
1. Ionic bond is a chemical bond formed through the X X Y or X Y
X
transfer of electrons from a metal atom to a non- 3
metal atom. Triple covalent bond
2. The metal atom loses its valence electrons to achieve
a stable duplet or octet electron arrangement. A cation
is formed. 5.4 Hydrogen Bond
3. The electrons are transferred to the valence shell of
the non-metal atom. 1. There are some atoms with high electronegativity.
4. The non-metal atom gains electrons to achieve a These include oxygen, nitrogen or fluorine atoms.
stable octet electron arrangement. An anion is formed. 2. Hydrogen bond is an attraction force between
5. These oppositely charged ions are attracted to each a hydrogen atom which is bonded to a high
other by strong electrostatic force. This strong electronegativity atom, with either nitrogen atom,
electrostatic force results in the formation of ionic oxygen atom or fluorine atom in other molecules.
bond (electrovalent bond). 3. For example, the hydrogen bond that exists between
two water molecules, H O.
2
5.3 Covalent Bond H H

1. Covalent bond is a chemical bond formed from the O Oxygen atom,
O with high electronegativity
sharing of valence electrons between non-metal
atoms. Hydrogen
2. Non-metal atoms can be: bond
(a) Elements of Group 15, 16, 17 H
(b) Carbon and silicon in Group 14 O
(c) Hydrogen
3. During sharing of electrons, the shared pair of H Covalent bond
electrons forms a covalent bond between two atoms. 4. Some of the phenomena that occur in daily life are
4. The atoms that are bonded together by covalent bond closely related to hydrogen bonding, for example:
produces a molecule. (a) Wet hair that sticks to each other
(b) Flipping pieces of paper more easily when
fingertips are wet with water








54

5. The table below shows the melting point and boiling are easily released and delocalised. Positively-
point of chlorine and ethanol. charged metal ions are formed.
3. The delocalised valence electrons move freely
Melting point Boiling point
Substance between the metallic structure and form the sea of
( C) ( C) electrons.
o
o
Chlorine –101.5 –34 4. Therefore, electrostatic force of attraction between
the sea of electrons and metal ions is produced.
Ethanol –114.1 78 Thus, a metallic bond is produced.
6. Although the boiling points of both chlorine and Positively
ethanol are low, the boiling point of ethanol is much Valence + + + + + + + + + + charged
electron
higher than that of chlorine due to the presence of + + + + + + + + + + metal ion
©PAN ASIA PUBLICATIONS
hydrogen bonds between the two molecules. + + + + + + + + + +
7. More heat energy is required to overcome the van der + + + + + + + + + + + + + + + + + + + +
Waals attraction forces between ethanol molecules
besides breaking the hydrogen bonds between the Delocalised electrons
from “sea of electrons”
ethanol molecules.
8. The solubility of ethanol in water is also due to the 5. Metals can conduct electricity because the
presence of hydrogen bond between ethanol molecule delocalised valence electrons in the sea of electrons
and water molecule. can move freely and carry electrical charges from
the negative terminal to the positive terminal.
5.5 Dative Bond
5.7 Ionic and Covalent Compounds
1. Dative bond is a covalent bond between two atoms
in which the shared pair electrons are originated from 1. Electrical conductivity
one atom only. (a) In solid state, ionic compounds do not conduct
2. Dative bond is also known as coordinate bond. electricity because the ions are attracted to each
3. Hydroxonium ion and ammonium ion are two other by strong electrostatic forces. Hence, these
examples of ions with dative bond. ions cannot move freely.
(a) Hydroxonium ion (b) Ionic compounds can conduct electricity in
molten or aqueous states because ions can
move freely and carry electrical charges.
Hydroxonium ion that
Hydrogen ion without is formed through the (c) Covalent compounds do not conduct electricity
in all states because they are composed of
electron in the shell formation of a dative bond.
H H + neutral molecules. Free moving ions do not
exist.
H O + H + H O H 2. Solubility in Water and Organic Solvent
(a) Most ionic compounds are soluble in water.
(b) Ionic compounds do not dissolve in organic
solvents.
Lone paired electrons in a water molecule are (c) Most covalent compounds are soluble in
contributed to the hydrogen ion to be shared together.
organic solvents.
(b) Ammonium ion (d) Covalent compounds do not dissolve in water.
H + 3. Melting and Boiling Points
H N H + H + H N H (a) Cations and anions in the lattice of ionic
compounds are attracted to each other by strong
H electrostatic forces. More heat energy is required
H to overcome the strong electrostatic forces.
(b) Due to high melting and boiling points, ionic
Ammonium ion is produced through the formation of compounds usually exist as non-volatile solids.
dative bond between hydrogen ion and nitrogen atom (c) Molecules in covalent compounds are attracted
in the ammonia. to each other by weak van der Waals force
of attraction. Less heat energy is needed to
5.6 Metallic Bond overcome the weak van der Waals forces of
1. Metal atoms have 1, 2, or 3 valence electrons. attraction between molecules.
2. Even in solid state, valence electrons of metal atoms (d) Due to low melting and boiling points, covalent
compounds usually exist as volatile liquids.





55

PAPER 1

Each question has four different answers, A, B, C and D. For each question, choose one answer only.

5.1 Basics of Compound Formation 6. An atom of element E has 12 neutrons. The nucleon
SPM
SPM number of element E is 23. Atom E loses electrons to
1. Ionic bond is formed when CLONE form ion E. How many electrons are there in ion E?
A non-metal atoms share electrons. A 1 C 10
B nucleus of atom attracts valence electrons. B 8 D 11
C nucleus of non-metal atoms attracts each other.
D metal atoms transfer electrons to non-metal atoms. 5.2 Ionic Bond
©PAN ASIA PUBLICATIONS

2. Which atom forms a cation? 7. Diagram 2 shows a snail. The snail shell contains a
SPM
SPM A Chlorine C Sodium SPM natural ionic compound.
SPM
CLONE CLONE
B Oxygen D Carbon
3. What is the meaning of covalent bond?
SPM A A bond is formed when metal atoms share electrons Diagram 2
SPM
CLONE
with each other to achieve a stable electron Other than carbon, what elements are contained in the
arrangement. ionic compound?
B A bond is formed when non-metal atoms share A Calcium and oxygen
electrons to achieve a stable electron arrangement. B Sodium and oxygen
C A bond is formed when non-metal atoms transfer C Calcium and hydrogen
electrons to metal atoms. D Sodium and hydrogen
D A bond is formed when metal atoms transfer
electrons to non-metal atoms. 8. Which substance is an ionic compound?
SPM A Carbon monoxide, CO
SPM
4. Which statement best explains the formation of a CLONE B Sulphur trioxide, SO
SPM covalent bond? C Silicon dioxide, SiO 3
SPM
CLONE 2
A Metal atoms share electrons with non-metal atoms. D Magnesium oxide, MgO
B Non-metal atoms share electrons with non-metal
atoms. 9. Which compound is formed by transferring electrons?
C Metal atoms donate electrons while non-metal SPM A Hydrogen chloride, HCl C Ammonia, NH
SPM
atoms accept electrons. CLONE B Lithium oxide, Li O D Oxygen, O 3
D Non-metal atoms donate electrons while metal 2 2
atoms accept electrons. 10. Diagram 3 shows the electron arrangement of a
SPM chemical compound.
SPM
5. Diagram 1 shows the electron arrangement of a CLONE + 2– +
SPM
SPM potassium ion.
CLONE
+ Q R Q
K
Diagram 3
What are the elements represented by Q and R?
Diagram 1
What is the number of valence electrons of the Q R
potassium atom? A Sodium Oxygen
A 1 B Oxygen Sodium
B 7 C Lithium Fluorine
C 8
D 9 D Fluorine Lithium



56 Question 2: Question 8:
SOS TIP Cation is positive ion that is produced when a neutral atom loses its Ionic compound is formed when metal reacts with non-metal.
valence electron.
Question 6:
56 Nucleon number – proton number (number of protons) = number of
neutrons

(c) Diagram 4.2 shows a lady is removing her nail polish using acetone.





Acetone




Diagram 4.2
Based on the diagram, answer the following.
©PAN ASIA PUBLICATIONS
(i) Explain why acetone is suitable to be used to remove the nail polish. [2 marks]



(ii) Can water replace acetone to remove the nail polish? Give your reason. [2 marks]



5. Table 1 shows the electrical conductivity and melting point of substances P, Q and R.
SPM Table 1
SPM
CLONE
Electrical conductivity in the state of
Substance Melting point (°C)
Solid Molten Aqueous
P No No No < -110
Q No No No 80 – 90
R No Yes Yes > 800

(a) (i) State the type of structure and bonding of substance P. [2 marks]
Structure:
Bonding:

(ii) Explain why substance P has a low melting point but substance R has high melting point.
HOTS Analysing [4 marks]




(b) State how the bonds are formed in:
(i) substance Q. [1 mark]


(ii) substance R. [1 mark]


(c) State why substance R can conduct electricity in molten and aqueous states but not in solid state. [2 marks]



65
Question 4: Question 5:
(c) (ii) You need to figure out the type of compound of nail polish. Consider if (a) (i) There are two structures in covalent compound, namely, simple
the compound is able to dissolve in the organic solvent. molecular structure and giant molecular structure. SOS TIP


65

PAPER 3


You are required to compare the electrical conductivity of molten X and molten Y.
Prepare the apparatus set-up as in Diagram 1 and carry out the experiment according to the given procedure.

Procedure:
1. Fill a crucible with solid X until it is half full.
2. Place carbon electrodes into the solid X.
3. Complete the circuit by connecting carbon electrodes to Batteries
©PAN ASIA PUBLICATIONS
switch, bulb and batteries.
4. Turn on the switch and observe whether the bulb is lighted up. Bulb Switch
Turn off the switch. Carbon
5. Then, heat the solid X until it is melted. Turn on the switch Crucible electrodes
again and observe whether the bulb is lighted up. Solid X
6. Steps 1 to 5 are repeated using solid Y.
Based on the experiments carried out, answer the following. Heat
(a) Complete the Table 1. [6 marks]
Diagram 1
Table 1
Compound Physical state Observation Inference
Solid
X
Molten
Solid
Y
Molten

(b) For this experiment, state the [3 marks]
(i) manipulated variable
(ii) responding variable
(iii) constant variable
(c) State one hypothesis for this experiment. [2 marks]
(d) State the operational definition of electrical conductivity this experiment. [2 marks]
(e) Explain why molten sulphur cannot conduct electricity. [2 marks]

Note:
If you are not able to carry out the experiment as described above, you can answer this question using the following
samples of data:


Compound Physical state Observation Inference
Solid Bulb does not light up Compound X conducts electricity in molten
X
Molten Bulb is lighted up state but not in solid state.
Solid Bulb does not light up Compound Y cannot conduct electricity in solid
Y and molten states.
Molten Bulb does not light up



















68

Answers





CHAPTER 1
CHAPTER 1 30. A Detergent: to clean fabrics
31. A Fractional distillation is to separate (c) (i) Cosmetic consultant
Paper 1 petroleum fractions based on their (ii) Biotechnologist
differences in the boiling points. (iii) Nutritionist
1. C 32. B Ethanol boils around 78˚C, whereas 2. (a) A systematic scientific method used
2. D water boils at 100˚C. Therefore, to solve science related problems.
3. C Energy is not a matter. Therefore, it is distillation is used to separate the (b) (i) Manipulated variable: Total
not a chemical as well.
ethanol that is dissolved in the water.
4. B Fungicide is to kill fungi, pesticide is 33. B Burette can measure accurately the surface area exposed to sunlight
Responding variable: Rate of
©PAN ASIA PUBLICATIONS
to kill pest.
evaporation
5. D Stabiliser is used to mix oil or fat and volume of solution up to two decimal (ii) Unfolded filter paper dries first
places in its accuracy.
water together without separating. 34. B but folded filter paper still wet.
Thickener is to thicken the food and 35. C Phenolphthalein changes from pink to (iii) The bigger the exposed surface
preservative is used to slow down the colourless when the alkaline solution area, the higher the rate of
rate of food decaying process.
is neutralised upon reaching end point.
evaporation.
6. B Sodium nitrite is a preservative to 36. B Gas coming out from the anode is (c) Making observation, making
make the meat lasts longer.
identifying
problem,
7. B oxygen gas. So, it is tested using a inference, hypothesis, identifying
glowing splinter.
making
8. B Nutritionist studies the nutritional 37. A variables, controlling variables,
value of the food. Dietitian is an 38. A planning experiment, collecting
expert in human nutrition and alters 39. A Alkali metal is very reactive and tends data, interpreting data and making
the patient's diet based on their to react with water and oxygen in the conclusion.
medical condition and individual air. 3. (a) Do not eat, drink, chase or run in the
needs. Nanotechnology engineer 40. A Hydrocarbon is flammable and should laboratory.
learns new things that can change the be kept away from heat source. Do not pour the chemicals back to
health, science, technology, and the 41. A Silver nitrate can be easily the reagent bottles.
environment on a molecular level. decomposed. Therefore, it must be (b) Use safety goggles when mixing or
Chapter 1 11. A Making inference means making 42. B Mercury, lead, arsenic, cadmium and (c) (i) To avoid dust or splashes of
9. B
heating chemicals.
kept away from sunlight.
10. D Hypothesis is to verify the inference
Keep flammable substances away
whether it is true or not.
from the heat source.
chromium are examples of heavy
metals.
explanation of an observation based
chemicals accidentally get into
43. C Poisonous chemicals must be stored
on past experience.
the eyes
properly and cannot be reached easily.
12. A
13. A In order to test the hypothesis, an
from toxic chemicals, either in
experiment is conducted. 44. D So it has to be locked in cabinet. (ii) To protect respiratory organs
the form of powder or fumes
14. D 45. C Adding water to concentrated acid (iii) To protect hands from any
may be very exothermic and the heat
15. D Hypothesis is a statement that relates released may vapourise the corrosive injury, exposure to chemicals or
the manipulated variable with the acid. Always add acid to the water infection
responding variable.
16. B (remember 3A: Always Add Acid to 4. (a) Potassium: Kept in paraffin oil
the water)
Hydrogen peroxide: Kept in dark

17. C 46. D bottles
18. B 47. B Ethanol: Kept in shady area and far
19. C 48. D from sunlight and heat source
20. B 49. D (b) (i) Phenomenon at which a person
21. B 50. A Writing a report is to keep a is exposed to mercury in a certain
22. A documentation for reference in the amount either accidentally
23. B The mass of beakers and volume of future. Data collected cannot be inhaled the mercury vapour or
beakers do not affect the result of altered and scientist should be honest touch the mercury spill until
the experiment. The type of salt used in recording the results obtained. the mercury is absorbed into the
(soluble or insoluble), will affect the More measurements should be done body through the skin
result of experiment and must be kept to get average value of measurement (ii) Nausea and vomiting
constant.
24. C to increase the accuracy. (iii) Inform the accident to the
teacher
immediately.
Next,
25. B Eyewash is a safety equipment in the make the spill site a restricted
laboratory. Paper 2
26. A Safety goggles is actually a personal area. Sprinkle sulphur powder
to cover up the mercury spill.
protective equipment a person should Section A Lastly, contact the Fire and
wear when handling dangerous 1. (a) A field of science that studies the Rescue Department for further
experiment. structures, properties, compositions
27. A and interactions between matters. action.
28. C Eyewash is a safety equipment to (b) (i) Insecticide, colouring and Section B
clean the parts of the eye in case of detergent 1. (a) Put some alkaline quicklime or
accident. (ii) Insecticide: to kill insect
29. D Fume chamber is a cupboard that Colouring: to give colour or slaked lime to neutralise the acidity
of the soil.
is used to carry out experiment that restore colour loss during food
involves the release of toxic gas. processing
126

26. B Sulphuric acid is a strong diprotic 44. B Fine salt dissolves faster. There is 0.02 (ii)
acid. It has the highest concentration g of salt per 1 cm of water in A but
3
of H ions. there is only 0.015 g of salt per 1 cm 3 Mass of zinc (g)
+
27. D of water in B. Therefore 3 g of salt
28. D Zinc powder in Experiment II has dissolves faster in 200 cm of water. 5.00
3
bigger total surface area. Rate of 45. B Higher temperature and concentration The curve at the
reaction of Experiment II is higher. of the solution will increase the rate of temperature of 30 °C
The volume of gas produced is reaction.
the same since the volume and 46. D
concentration of acid used are the 47. A Higher pressure also results in higher 1.75
same. temperature according to pressure’s
29. C Curve Q represents higher rate law.
of reaction. Therefore, higher 48. D In the reaction, copper (II) sulphate t 1 Time (s)
©PAN ASIA PUBLICATIONS
concentration of hydrogen peroxide is solution acts as catalyst. Magnesium 3. (a) (i) Set I: Average rate
needed. The volume of gas produced powder has larger total surface area 30 3 –1
in curve Q is lesser. So, the number of compare to magnesium ribbon. = 1.5 = 20 cm min
moles of hydrogen peroxide should be 49. C Effective collision is the collision Set II: Average rate
lesser. which causes a chemical reaction. 50
3
30. A Higher concentration of acid 50. B Increase in temperature will increase = 1.5 = 33.33 cm min –1
produces higher rate of reaction with the kinetic energy of the reacting (ii) Rate of reaction in Set II is
steeper gradient. Number of moles particles. Thus, increasing the higher
of hydrochloric acid is higher. So, frequency of collision between (iii) At higher temperature, kinetic
the volume of gas produced will be reacting particle. energy of particles increases
greater. 51. A and particles move faster.
350 kg 52. C Number of moles of reactants should Particles also gain extra energy
31. C = 1.167 kg min –1
300 min be the same because produces equal to overcome the activation
200 kg = 1.67 kg min –1 amount of hydrogen gas. energy.
120 min Frequency of collision between
+
120 kg = 2 kg min –1 Paper 2 H ions and calcium carbonate
60 min in Set II is higher.
100 kg = 1.11 kg min –1 1. (a) (i) Change in the volume of Frequency of effective collision
+
90 min hydrogen gas per unit time. between H ions and calcium
In one minute, 2 kg of sulphur trioxide (ii) 2HCl + Zn → ZnCl + H 2 carbonate in Set II is higher.
2
is produced under 450ºC. (iii) Change in the volume of gas. (b) (i) & (ii)
32. D (iv) Size of zinc Energy Chapter 7
33. D Higher temperature increases the (b) When potatoes are cut into smaller
kinetic energy of reacting particles. pieces.
34. D Heating the acid will increase the At smaller size, total surface area E a
temperature of hydrochloric acid. At exposed to hot water is bigger. E '
higher temperature, rate of reaction More heat is absorbed to cook the a
is higher. Copper (II) sulphate should potatoes. Zn + 2HNO 3
be the catalyst of the reaction. When (c) Rusting and photosynthesis
more water is added, the concentration 2. (a) Zn + H SO → ZnSO + H 2 Zn(NO ) + H 2
2
4
4
3
of acid decreases and this will reduce (b) (i) All sulphuric acid is used up.
the rate of reaction. (ii) 1.75 g Reaction path
35. A Catalyst provides an alternative path (c)
with lower activation energy. 4. (a) Size of calcium carbonate.
36. C Sulphuric Hydrogen (b) Measure the change in the volume of
37. A Sulphuric acid is a strong diprotic acid gas carbon dioxide per unit time.
acid. It has the highest concentration Burette (c) Change in the volume of carbon
+
of H ions. Basin dioxide gas can be observed and
38. A Catalyst provides an alternative path measured using burette.
with lower activation energy. (d) Temperature and concentration
39. A hydrochloric acid.
40. D Zinc Water (e) (i) Experiment II. Gradient of the
41. D Manganese (IV) oxide acts as a curve in experiment II is higher.
catalyst in decomposition of hydrogen (d) (i) At higher temperature, kinetic (ii) All hydrochloric acid and
peroxide. energy of particles increases calcium carbonate are fully used
42. D Changing the concentration or volume and particles move faster. up.
will affect the number of moles of Particles also gain extra energy (iii) Volume of gas collected is the
hydrogen peroxide and results in to overcome the activation same.
different volume of gas released. energy. Number of moles of carbon
43. A Reduce the size will increase the total Frequency of collision between dioxide gas in both experiments
+
surface area of zinc that reacts with H ions and zinc atoms increase. are the same
acid. Frequency of effective collision Number of moles of acid and
+
between H ions and zinc atoms calcium carbonate used in both
also increase. experiments are also the same.



139

©PAN ASIA PUBLICATIONS