Chemistry Perfect Score Module 2010 Guidelines

BAHAGIAN PENGURUSAN
SEKOLAH BERASRAMA PENUH DAN SEKOLAH KLUSTER

MODUL PERFECT SCORE
2010

CHEMISTRY

 Set 1
 Set 2
 Set 3
 Set 4

Chemistry Perfect Score Module 2010 1

CHEMISTRY PERFECT SCORE MODULE 2010
CONTENT

 Format of an instrument of chemistry
 Construct requirement
 Guidelines for answering paper 1
Guidelines &
1  Guidelines for answering paper 2
Anwering Techniques
 Guidelines for answering paper 3
 The common command words in paper 2 and 3
 The common diagram

 The structure of Atom
 Chemical Formulae and equations
2 Set 1
 Periodic Table of Elements
 Chemical Bonds

 Electrochemistry
3 Set 2
 Oxidation and Reduction

 Acids and Bases
 Salts
4 Set 3
 Rate of reaction
 Thermochemistry

 Carbon compounds
5 Set 4  Manufactured Substance in Industry
 Chemicals for Consumers

Question Validation & Construction Panel
1 Pn Wan Noor Afifah binti Wan Yusoff SBPI Gombak
2 En Che Malik bin Mamat SBPI BR
3 En Jong Kak Ying SMS Kuching
4 Pn Aishah Peong binti Abdullah SBPIT
5 En Ooi Yoong Seang SMS Muar


CHEMISTRY
PERFECT SCORE MODULE

GUIDELINES
&
ANSWERING TECHNIQUES

CHEMISTRY SPM


GUIDELINES AND ANSWERING TECHNIQUES FOR SPM CHEMISTRY PAPER

1.0 FORMAT OF AN INSTRUMENT OF CHEMISTRY BEGINNING SPM 2003

No Item Paper 1 Paper 2 Paper 3
(4541/1) (4541/2) (4541/3)
1 Type of instrument Objective test Subjective test Written Practical Test
Type of item Objective it Section A : Subjective Item :
Structured Item Structured Item
Section B : Extended Response Item:
2
Essay restricted response Item (Planning an experiment)
Section C :
Essay extended response Item
Number of question 50 (answers all) Section A : 6 (answer all) Structured Item :
Section B : 2 (choose one) 1/2 items (answer all)
3
Section C : 2 (choose one) Extended Response Item :
1 item
5 Duration of time 1 hour 15 minutes 2 hour 30 minutes 1 hour 30 minutes

2.0 CONSTRUCT REQUIREMENT

Construct Paper 1 Paper 2 Paper 3
Knowledge 20 m ( No 1- 20) 14 -
Understanding 15 m ( No 21 – 35) 21 -
Application 15 m ( No 36 – 50) 29 -
Analysis - 21 -
Synthesizing - 15 -
Science process - - 50
Total mark 50 100 50

3.0 TIPS TO SCORE “ A “ CHEMISTRY

3.1 Master the topics that contains the basic concepts of chemistry :
1. The structure of the atom
2. Chemical Formulae And Equations
3. Periodic Table
4. Chemical Bond

3.2 Familiarize with different types of questions as listed below and complete the previous SPM papers :
1. Objectives questions (MCQ) (Paper 1)
2. Structured questions ( Paper 2 & 3)
3. Essays (Paper 2)
4. Planning an experiment ( Paper 3)
5. Draw and label the diagram
6. Writing chemical equation( balanced equation, ionic equation, half equation)

3.3 Try to get :-
 40 marks above for paper 1
 60 marks above for paper 2
 40 marks above for paper 3 (Total = 180/2 =80 , A+ in SPM)
4.0 GUIDELINE FOR ANSWERING PAPER 1

4.1 Paper 1 questions test students on
1. Knowledge ( Number 1 – 20)
2. Understanding ( Number 21 – 35)
3. Application ( Number 36 – 50 )

4.2 Score in paper 1 Indicates student‟s level of understanding in chemistry:
Less than 20 – very weak
20 – 25 - weak
26 – 30 - average
31 – 39 - good
40 – 45 - very good
46 – 50 - excellent.

4.3 Answer all SPM objective question ( 2003 – 2009). Objective questions for each year contain all topics. If
your score in paper 1 is 40 and above, you will able to answer questions in paper 2 & 3 easily.


5.0 GUIDELINE FOR ANSWERING PAPER 2 ( STRUCTURE AND ESSAY)

5.1 Paper 2 questions test student on
1. Knowledge
2. understanding
3. analyzing
4. synthesizing .

5.2 Steps taken are:
1. Underline the command word and marks allocated for each question.
2. Match the command word to the mark allocated for each question. 1 point is awarded 1 mark.
3. Follow the needs of the question ( Refer to the command words, page ……. )
4. Unnecessary repetition of the statement in the question is not required.

5.3 Three types of questions which involve experiments in paper 2 :
I. Type 1
Describe an experiment on…………………Include a labeled diagram in your answer
1. Diagram
2. Procedure
3. Observation/example/data/calculation/equation/sketch of graph/conclusion
II. Type 2
Describe an experiment……………( The diagram will support your answer.)
1. No mark is allocated for a diagram
2. Procedures
3. Observation/example/calculation/equation/sketch of graph/conclusion
III. Type 3
Describe a chemical/confirmatory test for …….
1. Procedure
2. Observation
3. Conclusion

6.0 GUIDELINE FOR ANSWERING PAPER 3

6.1 Structure Question 1/2 Test The Mastery of 11 Scientific Skills
1. Observing
2. Classifying
3. Inferring
4. Measuring (burette , stopwatch, thermometer, voltmeter)
5. Predicting
6. Communicating( e.g construct table and draw graph)
7. Space-Time Relationship
8. Interpreting Data
9. Defining Operationally
10. Controlling Variables
11. Hypothesizing

Each answer is allocated mark as follows: 3 marks/2 marks/1 mark/0 Score : 11 X 3 = 33

6.2 Question 3 (essay) Test The Mastery of Planning Experiment .

Planning should include the following aspects :
1. Aim of the experiment/Statement of the problem
2. All the variables
3. Statement of the hypothesis
4. List of substances/material and apparatus – should be separated
5. Procedure of the experiment
6. Tabulation of data Score : (5 X 3) + 2 = 17

 The question normally starts with certain situation related to daily life.
 Problem statement/ aim of the experiment / hypothesis and variable can be concluded from the situation
given.
 State all the variables
 Manipulated variable :
 Responding variable :
 Constant variable : list down all the fixed variables to ensure the outcome of the responding variable
is related only to the manipulated variables.
 Separate the substances and apparatus
 Procedure :
 All the steps taken in the procedure must include the apparatus used, quantity and type of
substance ( powder, solution, lumps … etc).

 No mark is allocated for the diagram. The complete labeled diagram can help students in :
I. Writing the steps taken in the procedure
II. Listing the apparatus and materials

 Tabulation of data:
 The number of columns and rows in the table is related to the manipulated and responding
variables
 Units must be written for all the titles in each row and column of the table
 DO NOT WRITE the observation/inference/conclusion in the table.

7.0 THE COMMON COMMAND WORDS IN PAPER 2 & PAPER 3 CHEMISTRY
 The question normally starts with a command word.
 Students must know the meaning of the command word to make sure that the answer given is according to the
question’s requirement.
 Match the command word to the mark allocated for each question.
Command word Explanation/example
Give the name , not the formula.
Name/State the
Example: Name the main element added to copper to form bronze.
name
Wrong answer : Sn.
(paper 2 & 3)
Correct answer : Tin
Give brief answer only. Explanation is not required.
State
Example : State one substance which can conduct electricity in solid state.
(paper 2 & 3)
Answer : Copper
Write what is observed physically .
Example 1 : State one observation when magnesium powder is added to hydrochloric
acid. [ 1 mark]
State the Wrong answer : Hydrogen gas is released.
observation Correct answer : Gas bubbles are released
(Paper 2 & 3) Indicate the change of colour , give the initial and final colour of the substance/chemical.
Example 2: What is the colour change of copper(II) suphate solution. [ 2 marks]
Wrong answer: The solution becomes colourless
Correct answer : The blue colour of the solution becomes colourless
Give the answer with reasons to explain certain statement / fact / observation/ principal.
Example 1 : Explain why bronze is harder than pure copper [4 marks]
Correct answer :
- Copper atoms in pure copper are all of the same size and ...........1
Explain
- they are arranged in layers that can slide easily when force is applied .......... 1
(Paper 2 & 3)
- The presence of tin atoms in bronze that are different in size disturb the orderly arrangement
of atoms in bronze. ..........1
- This reduces the layer of atoms from sliding. .........1

Give the exact meaning
What is meant by..
Example: What is meant by hydrocarbon.
(Definition)
Wrong answer: A compound that contains carbon and hydrogen
(Paper 2 & 3)
Correct answer: A compound that contains carbon hydrogen only
State the method to conduct the test , observation and conclusion.
Example : Describe how to identify the ion present in the solution . [ 3 marks]
Describe chemical 3
Answer : - Pour in 2 cm of the solution in a test tube. Add a few drops of sodium
test
hydroxide solution and the test tube is shake the test tube .........1
(Paper 2 & 3)
- A reddish brown precipitate formed. .........1
3+
- Fe ions present ………1
State the method to conduct the test observation and conclusion.
Example: Describe the confirmatory test for gas released at the anode(oxygen). [ 3 marks]
Describe gas test. Wrong answer: Test with a glowing wooden splinter.
(Paper 2 & 3) Correct answer: - Place a glowing wooden splinter to the mouth of the test tube …….1
- The glowing wooden splinter is lighted up ……1
- Oxygen gas is released …….1

- No mark is awarded for the diagram. The diagram can help students write the steps taken in the
procedure.
Describe an - List of materials 1m
Can be obtained from the diagram
experiment - List of apparatus 1m
( 8 - 10 marks) - Procedure - ( 5 – 8 m)
(Paper 2) - Observation/tabulation of data/ calculation/sketch of the graph/ chemical equation /ionic equation
/conclusion …… etc.
- Any additional details relevant derived from the question.

Plan an Answer the question according the requirement :
experiment  Problem statement/Aim of experiment
( 17 marks)  Hyphotesis
( Paper 3)  Variables


 List of substances and apparatus
 Procedure
 Tabulation of data
Note: For question 3, unlike PEKA report students only need to answer according to what is stated in
the question.
- No mark for the diagram. Diagram can help student writing the steps taken in the procedure.
Describe the
process …
Describe the Give relevant details derived from the question.
structure ….
Describe and write
equation…
Describe how …
(Paper 2 & 3)
Make a prediction for something that might happen based on facts
Predict
Example: Experiment 1 is repeated using a larger beaker.Predict the increase in temperature
(Paper 2 & 3)
Answer : The increase in temperature is lower than experiment 1.
Compare Give the similarities and differences between two items/ situations
(Paper 2)
Give differences between two items/situations
Differentiate
Example : State three differences between ionic and covalent compound.
(Paper 2)
Answer : State three properties of ionic compound and three properties covalent compound
Draw a complete set up of apparatus
Draw a labeled (i) Functional set up of apparatus
diagram of the (ii) Complete label
apparatus (iii) Shade solid, liquid and gas correctly.
(Paper 2) (iv) Draw an arrow and label ‟ heat‟ if the experiment involves heating
(i)Ionic compound – The number of electrons in each shell is correct, 2 electrons in the first shell
and 8 electrons in the second and third shell.
Draw a diagram to – Show the charge of each particle.
show the bonding – Write the symbol of each element at the centre of the ion.
formed in the (ii) Covalent compound
compound  The number of electrons in each shell is correct, 2 electrons in the first shell and
(Paper 2) 8 electrons in the second and third shell.
 The number of atoms sharing pair of electrons is correct.
 Write the symbol of each element at the center of each atom in the molecule.
Draw graph as follows :
 Label the two axis with the correct unit
 Choose suitable scale, the size of the graph should be at least ¾ of the size of the graph
paper.
Draw graph  Plot all the points correctly
(Paper 3)  Smooth graph ( curve or straight line )
 For the determination of the rate of reaction
(i) Draw a tangent at the curve.
(ii) Draw a triangle at the tangent
Calculate the gradient of the tangent
Draw the energy  Draw an arrow for the vertical axis only and label with energy .
level diagram  Draw two horizontal lines for the reactants and products
( Paper 2)
Draw the  Solid : Draw at least three layers of particles closely packed in orderly manner and the are not
arrangement of overlap.
particles in solid,  Liquid : The particles packed closely but not in orderly manner
liquid and gas.  Gas : The particles are very far apart from each other
(Paper 2)
Draw the direction of
electron flow Draw the direction for the flow of electrons on the circiut, not through the solution.
(Paper 2 /3)
Write chemical  Write the balanced chemical equation
equation  Differentiate :
(Paper 2 & 3) (i) Balanced chemical equation
(ii) Ionic equation
(iii) Half equation for oxidation
(iv) Half equation for reduction
Calculate  Show all the steps taken
(Paper 2 & 3)  Give final answer with unit.
Classify  Draw table to represent the classification.
(Paper 3)


8.0 THE COMMON DIAGRAM IN CHEMISTRY SPM SYLLABUS

Labelled Diagram for the Setup of Apparatus/ Structural Formula

The Structure Of
Atom

Determination of
melting and boiling
point of naphthalene

Determination Melting Point Determination of Freezing Point
Particle arrangement
in solid , liquid and
gas

Solid Liquid Gas

Chemical Formulae
and Equations
Determination of
empirical formula

Magnesium oxide Copper(II) oxide

Reaction between sodium/potassium with oxygen
Periodic Table

Reactions between chlorine gas and iron
Chemical Bond The .
electron arrangement
in ionic and covalent
compound.
* Make sure you can
explain the formation
of the bonds
accurately

Sodium chloride Magnesium chloride

Tetrachloromethane Carbon dioxide

Electrochemistry

Molten Lead (II )bromide Copper(II) sulphate solution (Copper electrode)

Electrolysis

Sulphuric Acid ,
Potassium sulphate
Hydrochloric acid
( gas bubbles released ) Electroplating an iron key

Purifying an impure metal


Voltaic cell

Simple cell Daniell cell (porous pot)

Daniell cell (Salt bridge )

1.Heating of copper(II) carbonate and confirmatory test for carbon dioxide

ACID ,BASE &
SALT

1. Heating of
carbonate 2. Preparation of soluble salt (Method I) – Sodium nitrate
compound and
confirmatory test
for carbon dioxide

2. Preparation of
soluble salt
(Method I & II)

3. Preparation of
insoluble salt 3.Preparation of soluble salt (Method II) – Copper(II) sulphate

4. Preparation of insoluble salt – Lead(II) iodide


H CH3

C = C

Manufactured
Substances in H H
industry Propene
Polypropene

Polymerisation H Cl H Cl H

C─ C─C─ C─ C

H H H H H

Chloroethane Polivinly chloride (PVC)

Alloys
Arrangement of
atoms in a metal Arrangement of atoms in a pure metal Arrangement of atoms in alloy(Bronze)
and an alloy

Rate of reaction Gas
is collected using
water displacement
for carbon dioxide
gas, oxygen and
hydrogen

Redox
1.Usage of tube U ,

oxidising agent :
a. Chlorine
Water
b. Bromine
Water
c. Potassium
manganate (VII)
acidified

Reduction agent
a.KI
b.KBr
c.FeSO4
* Mark the positive
and negative terminal
Iron
2.Rusting of iron
Diagram to show the rusting of iron


Thermochemistry

Determination of
Heat Combustion

Carbon Compound

Alcohol Dehydration

Oxidation of alcohol and esterification through reflux

Alcohol Dehydration Oxidation of alcoholand esterification Through reflux


CHEMISTRY PERFECT SCORE MODULE

SET 
1. The Structure of Atom
2. Chemical Formulae and Equations
3. Periodic Table of Elements
4. Chemical Bonds


SET 1
PAPER 2
SECTION A – STRUCTURE QUESTION

1 Table 1 shows four substances and their respective chemical formulae

Substance Chemical Formula
Bromine Br2
Nickel Ni
Phenol C6H5OH
Sodium chloride NaCl

Table 1

(a) State all substances that exist as molecules.

………………………………………………………………………...………………………………
[1 mark]
(b) What is the state of matter for bromine at room temperature?

.…………………………………………………………………………………………………………
[1 mark]
(c) State the substance that can conduct electricity in solid

….………………………………………………………………………………………………………
[1 mark]
(d) Draw the particles arrangement of the substance in (c) at room temperature.

[1 mark]
(e) Name the particles present in sodium chloride.

.…………………………………………………………………………………………………………
[1 mark]
(f) Diagram 1 shows the temperature against time when solid phenol is heated.
Temperature/◦ C

S
Q R
T1

T0
P
Time/s
Diagram 1
(i) State the melting point of phenol.

.……………………………………………………………………………………………………
[1 mark]
(ii) Explain why there is no change in temperature from Q to R.


……………………………………………………………………………………………………
[1 mark]
(iii) State how the movement of naphthalene particles changes between R and S during
the heating.

..……………………………………………………………………………………………………
[1 mark]

2 Diagram 2 shows the cooling curve of molten naphthalene beginning from 90oC.
Temperature/◦C

9
0
P Q
T

R

Time/min
0 t1 t2 t3
Diagram 2

Based on diagram 2, answer the following question.

(a) State the melting point of naphthalene.

……………………………………………………………………………………………….…………
[1 mark]
(b) State the time when all the liquid naphthalene has frozen.

……………………………………………………………………………………………….…………
[1 mark]
(c) Why does the temperature of naphthalene remains constant from t1 to t2?

………………………………………………………………………………………….………………

………………………………………………………………………………………………………….
[1 mark]
(d) (i) What is the type of particles in naphthalene?

.………………………………………………………………………………………….…………
[1 mark]
(ii) Draw the arrangement of particles of naphthalene at point P and R in the space
provided.

Point P Point R
P R [2 marks]
(e) State the state of matter for naphthalene at the time


(i) t1 to t2:

………………………………………………………………………….…………..…….………

(ii) t2 to t3:

……………………………………………………………………………………………………..
[2 marks]

(f) When naphthalene is heated with direct flame, naphthalene changes from solid to gas.
Name the process that occurs.

…………………………………………………………………………………………………………
[1 mark]

3 An experiment is carried out to determine the melting point of solid X. . Solid X is heated using
water bath. The temperature of X is recorded at 30 seconds intervals as shown below

Time/second 0 30 60 90 120 150 180 210
Temperature/oC 70 77 80 80 80 82 85 95

(a) Draw the set up of the apparatus to carry out this experiment.

[ 2 marks ]

(b) Draw the arrangement of particles in X at 77oC

[ 1 mark ]


(c) On the graph paper, draw the graph of temperature against time for the heating of X

[4 marks]


(d) (i) Show on your graph, how the melting point of X is determined
[1 mark]
(ii) What is meant by melting point?

……………………………………………………………………………………………………..

……………………………………………………………………………………………………..
[1 mark]
(e) Explain why there is no change in temperature from 60 second to 120 second.

……………………….....................…………………..……………………….…….......………...
.
………………………………………………....................………………………….…......……...
[1 mark]
4 Diagram 4 shows the apparatus set up of an experiment to determine the empirical formula of
copper oxide.
Copper oxide
Hydrogen gas

Porcelain dish

Heat

Anhydrous calcium chloride, CaCl2
Diagram 4

(a) What is the meaning of chemical formula?

.........………….………………………………………………………………………………..........

[1 mark]
(b) (i) Name an acid and metal that can be used to prepare hydrogen gas in this
experiment.

…………………………………………………………………………………………………...
[2 marks]
(ii) Write a balanced chemical equation for the reaction between the acid and the metal in
(b) (i).

………….………………………………...………........………………………………..………

[2 mark]
(c) State one precautionary step that must be taken before the copper oxide is heated.

………….……...……………………………………………………………….......……………….
[1 mark]


(d) Table 4 shows the results of an experiment carried out by a student.

Mass of combustion tube + porcelain dish 30.24g
Mass of combustion tube + porcelain dish + copper (II) oxide 32.26g
Mass of combustion tube + porcelain dish + copper 31.86g

Table 4

(i) Calculate the number of moles of copper in this reaction.
[Relative atomic mass : Cu = 64]

[1 mark]
(ii) Calculate the number of moles of oxygen in this reaction.
[Relative atomic mass : O = 16]

[1 mark]
(iii) Determine the empirical formula of copper oxide.

[2
marks]
(e) Name another metal oxide which uses the same method to determine the empirical
formula.

……..…………………………………………………………………………………….….………
[1 mark]
(f) M is a reactive metal. How to determine the empirical formula of the oxide of M.

..............................................................................................................................................
[1 mark]

5 Diagram 5 shows the apparatus set-up to determine the empirical formula of oxide metal M.

M oxide

Dry hydrogen gas

Asbestos paper

Diagram 5
(a) (i) Name two chemicals used to prepare hydrogen gas in the laboratory.

.....................................................................................................................................
[2 marks]

(ii) Write a chemical equation for the reaction in (a)(i).

…………………………………………………………………………….……………….....
[2 marks]

(b) Table 5 shows the result of the experiment:

Mass of combustion tube + asbestos paper 39.25 g
Mass of combustion tube + asbestos paper + M oxide before heating 47.95 g
Mass of combustion tube + asbestos paper + product after heating 44.75 g
Table 5

(i) Determine the empirical formula of M oxide.
[Relative atomic mass of O=16, M=55]

[4 marks]
(ii) Write a chemical equation for the reduction of M oxide by hydrogen gas.

...................................................................................................................................
[2 marks]
(c) State one precautionary step that must be taken when carrying out the experiment.

............................................................................................................................................
[1 mark]
(d) Can the empirical formula of magnesium oxide be determined by the same method?
Explain your answer.

.............................................................................................................................................

.............................................................................................................................................
[2 marks]


6 Diagram 6 shows the apparatus set-up of an experiment to determine the empirical formula of
magnesium oxide.
Lid

Magnesium Crucible
ribbon

Diagram 6

Result:
Mass of crucible + lid = 24.0 g
Mass of crucible + lid + magnesium ribbon = 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]
(iii) determine the empirical formula of magnesium oxide.

[1 mark]

(iv) write the chemical equation for the reaction in the experiment.

……………………………………………………………………………………………………
[2 marks]
(c) Why the crucible lid is open 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 apparatus set-up for the experiment.

[2 marks]

(e)Describe the steps that should be taken to ensure that all the air in the combustion tube has
been expelled.

.................................................................................................................................................

….............................................................................................................................................

.................................................................................................................................................
[1 mark]
7 Diagram 7 shows the symbols for atom of elements P, Q, and R.

P Q R
R Y

Diagram 7

(a) (i) Write the electron arrangement of atom P.

……………………………………………………………………………………….…..….....…
[1 mark]
(ii) State the period and the group for element P in the Periodic Table.

Period : ….…………………………………………………………………………….….……..

Group : ………………………………………………….………..............................................
[2 marks]

(b) (i) What is the proton number of element Q?

...........................................................................................................................................
[1 mark]

(ii) Atom of element Q has a nucleon number of 19. Calculate the number of neutrons in
atom Q.


…………………………………………………………………………………………………….
[1 mark]

(iii) Write the the standard representation of element P

…........................................................................................................................................
[1 mark]
(b) Element Q and R are located at the same Group in the periodic table of element.
Compare reactivity of element Q and R. Explain your answer

………………………………………………………………………………………………………....

…………………………………………………………………………………………………………

……………………………………………………………………………………………………........

………………………………………………………………………………………………………….
[4 marks]
(c) Element P can react with sodium to form a compound

(i) Name the type of bond in the compound formed between atoms P and sodium.
…………………………………………………………………………….................................
[1 mark]
(ii) State one physical property of the compound in (c)(i).

..…………………………………………………………………………….................................
[1 mark]
(d) Element P can also react with carbon to form a compound. Draw the electron arrangement
for the compound formed.
[Proton number of C = 12 ]

[2 marks]

8 Table 8 shows the proton numbers of elements X, Y and Z.

Elements Proton Number

X 12
Y 8
Z 6
Table 8

(a) Write the electron arrangement for atom X

…………………………………………………………………………………………………………
[1 mark]
(b) X and Y react to form a compound

(i) What type of bond holds atom X and Y together?

……………………………………………………………………….……………………………
[1 mark]


(ii) What happen to atom X during the formation of the compound with atom Y?
Explain why
………………….……………………………………………..................................................

..……………………………………………………………………..........................................

……………………………………………………………………………………………………
[2 marks]
(iii) Draw the electron arrangement of the compound formed in (b)(ii)

[2 marks]

(iv)State one physical property of the compound formed

..……………………………………………………................................................................
[1 mark]

(c) Y can react with Z to form a compound.

(i) What is the molecular formula of the compound formed?

………………………….......................................................................................................
[1 mark]
(ii) What is the relative molecular mass of the compound in c(i).
[ Given that relative atomic mass Z = 12; Y= 16]

……………………………………………………………………………………………………..
[1 mark]
9 Diagram 9 shows the position of several elements P, Q, R, S, T, U and W in the Periodic
Table of Elements

P
Q T V U
R S W X

Diagram 9

Using the symbols P, Q, R, S, T, U and W, answer the following questions.
(a) State one metal and one non- metal
Metal:….………………………………………………………………………………………….……

Non-metal:…………………………………………………………………………………………….
[1 marks]


(b) Write the electron arrangement of atom V.

..……………………………………………………………………………………………………….
[1 mark]
(c) Which of the elements has the biggest atomic radius?

……………………………….…………………………………………………………………………
[1 mark]
(d) Compare the electronegativity of elements Q, T, V and U. Explain your answer.

………………………………………..………………………………………………………………..

………………………………………………………………………………………………………….

………………………………………………………………………………………………………….

………………………………………………………………………………………………………….
[3 marks]
(e) Write the formula of the ion formed by Q.

..…………………………………………………….………………….………………………………
[1 mark]
(f) State the element that is chemically inert. Why?

…..……………………………………………………………………..………………………………
[1 mark]
(g) Write an equation for the reaction between R and U.

…....…………………………………………………………………..………………………………
[2 mark]
(h) State one special characteristic of S.

……….………………………………………………………………..……………………………….
[1 mark]
10 Table 10 shows the elements P, Q, T and U in the Periodic Table of elements. The symbols do
not represent the actual symbols of the element.

Element Group Period
P 2 3
Q 17 3
T 14 2
U 18 1
Table 10
Answer the following question based on the information given in Table 10,

(a) (i) state the number of valence electron in atom Q

.........................…………………………………………………………………………………..
[ 1 mark]
(ii) write the electron arrangement of atom Q

........................…………………………………………………………………………………..
[ 1 mark]
(b) (i) write the formula of the ion formed from atom P

........................…………………………………………………………………………………..
[ 1 mark]

(ii) state the element which will form an ionic compound with element P.

...........................………………………………………………………………………………..
[ 1 mark]

(iii) Based on your answer in (b) (ii), write the chemical formula of the compound formed

…………………………………………………………………………………………………..
[ 1 mark]
(c) Element U is used to fill weather balloons. Why element U is more suitable than hydrogen for
this purpose?

……………….........…………………………………………………………………………………..
[ 1 mark]
(d) Draw the electron arrangement of the compound formed between element T and
element Q.

[2 marks]

(e) State one physical property of the compound formed in (d)

.........………………………………….………………………………………………………………..
[ 1 mark]

11 Diagram 11 shows the chemical symbols which represent element P, Q, R and S.
23 16 14 35

11 P 8 Q 6
6 R 17 S
X Diagram 11 T
(a) (i) Write the electron arrangement of atom P.

………………………………………………………………………………...……………
[1 mark]
(ii) State the period and the group for element Q in the Periodic Table.

Period : ….………………………………………………………………………………..

Group : ………………………………………………….…………………………...........
[2 marks]
(b) Atoms of P and Q can react to form a compound.
(i) Name the type of bond in the compound formed between atoms P and Q.

………………………………………………………………………………………………
[1 mark]


(ii) Draw the electron arrangement for the compound formed.

[2 mark]
(c) Atoms of R and S can also react to form a compound. Draw the electron arrangement
for the compound formed.

[ 2 marks]
(d) Compare one physical property of compound formed in (b) and (c). Explain your
answer.

…………………………………………………………………………………..…………………

………………………………………………………………………………………………..……

………………………………………………………………………………………………..……

……………………………………………………………………………………………………..

…………………………………………………………………………………..…………………
[4 marks]

12 Table 12 shows the melting point, boiling point and electrical conductivity of substances P,
Q, R, and T .

Electrical conductivity
Substance Melting point (oC) Boiling point (oC )
Solid Molten
P 805 1460 No Yes
Q 1549 2950 Yes Yes
R -210 -153 No No
T -7 59 No No
Table 12
(a) Which of the substances is a metal ?

…………………………………………………………………………………………………………
[1 mark]


(b) (i) State the type of particle in substance P

.……………………………………………………………………………………………………
[1 mark]
(ii) Explain why substance P cannot conduct electricity in solid but can conduct electricity
in molten state.

...........................................................................................................................................

...........................................................................................................................................
[2 marks]
(c) (i) What is the physical state of R and T at room temperature ?

R : .....................................................................................................................................

T : .....................................................................................................................................
[2 marks]
(ii) Draw the arrangement of particles in substance T at room temperature.

[1 mark]
(iii) Explain why the melting and boiling points of substance R and T is low ?

….…………………………………………………………………………………………………
[1 mark]


PAPER 2
SECTION B: ESSAY

13 (a) Diagram 13.1 shows two isotopes of an element X

35 37

17 X 17 X
Diagram 13.1
(i) State the number of neutron in each isotope
[2 marks]
(ii) State two similarities and two differences between the isotopes
[4 marks]

(b) Diagram 13.2 shows an atom of element P.
The letter used is not the actual symbol of the element.

X 6p + 6n
R

Diagram 13.2
.
(i) Describe the atom shown in Diagram 13.2
[4 marks]
(ii) Atom of element Q has 7 neutron, which is in the same group with P. Compare atom P
with the atom Q
[4 marks]
(c) X is a substance which melts at 71oC and boils at 314oC

(i) Sketch a graph of temperature against time when molten X at 100oC is cooled to 60oC.
[2 marks]
o
(ii) Based on the graph in (c)(i), state the physical state of substance X at 71 C and explain
the changes in terms of the kinetic energy and the arrangement of particles
[2 marks]
14
3
1 mole of any gas occupies 24 dm at room condition.

(a) Explain why 16 g of oxygen occupies the same volume as 22 g of carbon dioxide at room
condition.
[ 4 marks ]
(b)
Caffeine is one of the substances in coffee. Caffeine consists of 0.48 % of carbon, 0.05 % of
–1
hydrogen, 0.28 % of nitrogen and 0.16 % of oxygen. The molar mass of caffeine is 194 g mol .

Based on the information above, determine the empirical formula and molecular formula of
caffeine.
[8 marks]


(c)
Fertilisers usually have a high content of nitrogen. Nitrogen is needed to increase the growth
of plants such as vegetables. The following substances are the examples of fertiliser which
are used by farmers .
 Ammonium suplhate, (NH4)2SO4
 Urea, CO(NH2)2
 Hydrazine, N2H2

Calculate the percentage of nitrogen by mass in each of the three fertilizers given above
and hence determine the best fertiliser a farmer should used for his plants.

[8 marks]
15 (a) Diagram 15.1 shows the standard representation for sodium element

Diagram 15.1
State three information that can be deduced from diagram 15.1
Draw the atomic structure of sodium atom.
[6 marks]
(b) Diagram 15.2 shows the empirical formula of glucose:

Diagram 15.2

(i) What is the meaning of empirical formula ?
(ii) The relative molecular mass of glucose is180, determine the molecular formula of
glucose.
[4 marks]
(c) (i) An iron chloride compound contains 2.80 g of iron and 5.32 g of chlorine.
Determine the empirical formula of the compound.
[Relative atomic mass: Fe = 56, Cl = 35.5]
[4 marks]
(ii) Write a chemical equation to represent the reaction between iron and chlorine.
Calculate the volume of chlorine gas that react completely with 2.80 g iron.
[1 mole of gas occupied 24 dm3 at room temperature and pressure]
[6 marks]

16 (a) What is meant by empirical formula?
[1 mark]

(b) A carbon compound contains 92.3% of carbon and 7.7% of hydrogen by mass.
The relative molecular mass of this compound is 78. Find the molecular formula of this
compound.
[Relative atomic mass: C=12; H=1]
[5 marks]
(c) Describe how you could determine the empirical formula of magnesium oxide in the
laboratory. Your description should include
 procedure of experiment
 tabulation of result
 calculation of the results obtained
[Relative atomic mass: O=16; Mg=24]
[11 marks]

(d) Magnesium can reduce copper oxide to copper.
Explain why the empirical formula of the copper oxide cannot be determined by heating the
mixture of copper oxide and magnesium powder.
[2 marks]

17 Table 17 shows the proton number and nucleon number of atom of elements Q and R.
Atom proton number nucleon number
Q 9 19
R 6 12
Table 17

(a) (i) Write the electron arrangement of atoms Q and R.
[2 marks]

(ii) State the number of neutrons and number of electrons in atom Q.
[2 marks]

(b) The reaction between Q and R forms a compound.
Describe the formation of the compound.

[8 marks]
(c) State the change of the reactivity of Group 1 and Group 17 elements in the
PeriodicTable of Elements when going down the group.
Explain your answer.

[ 8 marks]


PAPER 2
SECTION C: ESSAY

18 (a) Diagram 18 shows the electron arrangement of a compound formed from the reaction
between element Y and element Z
These letters are not the actual symbols of the elements.

+

Z Y

Diagram 18

(i) Based on diagram 18, write the electron arrangement for atoms of element and
element Z.
Explain the position of element Y in the Periodic Table of the Elements.
[6 marks ]
(ii) Element Y can react with sodium and sodium hydroxide to form compounds.
Write the chemical equation to represent the reaction between
 Y and sodium
 Y and sodium hydroxide
[4 marks ]
(b) Table 18 shows the proton number for atoms P, Q and R.
These letters are not the actual symbols of the elements.

Elements Proton number
P 11
Q 17
R 6
Table 18

By referring to the information in table 18, explain how two compounds can be formed from
these elements. The two compounds should have different types of bond.

[10 marks ]


PAPER 3
STRUCTURE

19 An experiment is conducted to find out the freezing point of liquid naphthalene. A boiling tube
containing molten naphthalene at 95 °C is allowed to cool in a conical flask to room temperature.
The temperature of naphthalene is recorded at every half-minute intervals. Diagram 19 shows the
reading of the thermometer for this experiment.

95 90 90 90

90 85 85 85

85 80 80 80

Initial temperature Temperature at Temperature at Temperature at
0 s : ……… 30 s : ……… 60 s : ……… 90 s : ………

85 85 85 85

80 80 80 75

75 75 70

Temperature at Temperature at Temperature at Temperature at
120 s : ……… 150 s : ……… 180 s : ……… 210 s : ………

Diagram 19

(a) Record the temperature in the spaces provided in Diagram 19.
[3 marks]
(b) Construct a table to record the time and temperature of the experiment.

[3 marks]
(c) (i) Draw a graph of temperature against time.

[3 marks]

(ii) On the graph, mark the freezing point of naphthalene..
[3 marks]
(d) (i) What is meant by freezing point ?

……..………………………………………………………………………………………………

……………………………………………………………………………………………………..
[3 marks]
(ii) Explain why the temperature of naphthalene remains constant form 90th seconds to
150th seconds during the cooling process.

…..…..……………………………………………………………………………………………

….…………………………………………………………………………………………………

….………………………………………………………………………………………..……….
[3 marks]


(e) Why is the boiling tube placed in the conical flask during the cooling?

…………………………………………………………………………………………………………

…………………………………………………………………………………………………………
[3 marks]
(f) Diagram below shows the particles arrangement of four substances.

+ - + -
Na Na Na Na Na Cl Na Cl Cl Cl O H O
Cl Cl
- + - +
Na Na Na Na Cl Na Cl Na H
Cl Cl O O

Na + - + -
Na Na Na Na Cl Na Cl Cl Cl O H O

P Q R S

Classify P, Q , R, and S into element and compound.

Element Compound

[ 3 marks ]

20 A student carried out an experiment to determine the empirical formula of magnesium oxide.
The step and apparatus set-up of the experiment are shown in Diagram 20.

Step Set-up of apparatus
1. Crucible and lid are weighed

2. Crucible, lid and magnesium ribbon
are weight

3. Magnesium and ribbons heated until
the reaction is complete

4. Crucible, lid and magnesium oxide
are weighed when cooled

Diagram 20


(a) Complete the following table by stating the observations and related inferences in the
experiment.

Observation Inferences

(i) (i)

(ii) (ii)

[6 marks]
(b) Record the reading to two decimal places for

The mass of crucible and lid :…………….g

The mass of crucible, lid and magnesium ribbon: …………. g

The mass of crucible, lid and magnesium oxide when cooled: ………… g

[3 marks]

(c) (i) What is the mass of magnesium that has been used?

(ii) What is the mass of oxygen which reacted with magnesium?

(iii) Determine the empirical formula of magnesium oxide.
Use the information that the relative atomic mass, Mg = 24 and O = 16

[3 marks]

(d) Based on your answer in (c)(iii), how many moles of magnesium and oxygen atoms have
reacted?

[3 marks]
21 Elements in Group 1 of the Periodic Table of Elements can be
Chemistry Perfect Score Modulebased on the reactivity of the elements with water.
arranged 2010 36

An experiment is carried out to investigate the statement above. Table 21 shows the
apparatus set up and the observations for the experiment to determine the reactivity of the
Group 1 elements based on their reactions with water.

Apparatus set-up Observation towards the metal
Lithium
Lithium moves slowly on the surface of the
))
water water with a “hiss” sound.

Potassium
)) ) )
))) water Potassium moves vigorously and randomly
on the surface of the water with a “hiss”
sound.

sodium

)) ) water Sodium moves quickly and randomly on the
surface of the water with a “ hiss” sound.

Table 21

(a) State the variables that are involved in the experiment.

Name of variables Action to be taken
(i) Manipulated variable: (i) The way to manipulate variable:

……………………………………….. ………………………………………………..

………………………….…………….. ………………………………………………...

(ii) Responding variable: (ii) What to observe in the responding
variable:
………………………………………… ………………………………………………..

………………………………………… ………………………………………..………

(iii) Controlled variable: (iii) The way to maintain the controlled
variable:
….……………………………………..
………………………………………………
…..……………………………………..
……….………………………………………
[6 marks]

(b) State one hypothesis for the experiment.

………………………….................………………………………….......…………………………

……………………………………………………………………........................…………………
[3 marks]

(c) Based on the observations in the diagram 21, arrange lithium, potassium and sodium in the
descending order of reactivity of metals towards water.

Descending order of reactivity of metals towards water.
[3 marks]

(d) Solution X was produced from the reaction of sodium with water. Classify the ions that exist in
solution X into positive ions and negative ions.

Positive Ions Negative Ions

[3 marks]

PAPER 3
ESSAY
1)
2) 22
“When lithium metal is put in water, it moves very slowly on the surface of the water. When sodium
metal is put in water, it moves fast and produces “hiss” sound. When potassium metal is put in water, it
moves very fast and produces small explosions”.
Metal

Water

3)
4)
5)
6) Plan an experiment in the laboratory to investigate the reactivity of lithium, sodium and
potassium with water The planning of your experiment must consist of the following:
7)
(a) Aim of experiment
(b) Hypothesis
8) (c) All the variables
(d) List of substances and apparatus
(e) Procedure of the experiment
(f) Tabulation of data
[17 marks]


CHEMISTRY PERFECT SCORE MODULE

SET  

1. Electrochemistry
2. Oxidation and Reduction


1 Diagram 1 shows the set-up of the apparatus to investigate the electrolysis of molten
lead(II)bromide.
The solid lead(II) bromide is heated until it is completely melted. All the observation are
recorded.

Carbon electrodes

Solid lead(II)bromide

heat

(a) What is the meaning of electrolysis?

…………………………………………………………………………………….
[ 1 mark ]
(b) State the ions present in lead(II) bromide.

……………………………………………………………………………………
[ 1 mark ]
(c) State energy change in the process.

…………………………………………………………………………………..
[ 1 mark ]
(d) In solid, the bulb does not glow , but in molten the bulb glows brightly.
Explain .

……………………………………………………………………………………

……………………………………………………………………………………
[ 2 marks ]
(e) (i) State the observation at anode.

………. …………………………………………………………………………
[ 1 mark ]
(ii) Write half-equation for the reaction at anode.

………………………………………………………………………………….
[ 1 mark ]

(f) (i) State the name of product formed at cathode.

………………………………………………………………………………….
[ 1 mark ]
(ii) What is the process that occurred at cathode.

…………………………………………………………………………………..
[ 1 mark ]


2. Diagram 2 shows the set-up of an electrolytic cell. Beaker X contains the components of a simple
chemical cell whereas electrolysis takes place in Beaker Y.

V

Magnesium plate
Zinc plate Carbon rods

Zinc sulphate Copper(II)
solution sulphate solution
Beaker X Beaker Y

Diagram 2

(a) (i) State the name of the cations present in the solution of Beaker Y.

............................................................................................................................................
[1 mark]
(ii) Mark the negative terminal and positive terminal in Beaker X
[1 mark]
(b) (i) What is the colour change of copper(II) sulphate solution?

............................................................................................................................................
[1 mark]
(ii) Explain your answer in (b) (i).

.............................................................................................................................................
[1 mark]
(c) (i) What is the product formed at the negative terminal of Beaker X?

.............................................................................................................................................
[1 mark]

(ii) Write a half equation for the reaction that occurs at the negative terminal of Beaker X.

………………………………………………………………………………………………………
[1 mark]
(d) (i) Name the type of reaction that occurs at the cathode in Beaker Y.

……………………………………………………………………………………………………….
[1 mark]

(ii) If the zinc plate is replaced by a copper plate, describe what will happen to the voltmeter
reading.Explain your answer.

…. ..………………………………………………………………………………………………..

………………………………………………………………………………………………………..
[2 marks]


3 Diagram 3 shows the set- up of apparatus to investigate the reaction between potassium iodide solution
and chlorine water through the transfer of electrons at a distance.

G

Electrode P Electrode Q

Potassium iodide Chlorine water
solution

Dilute sulphuric acid

Diagram 3

(a) What is the function of dilute sulphuric acid?

…………………………………………………………………………………………………………….
[1 mark ]
(b) On the diagram 3, draw the direction of the flow of electrons.
[1 mark ]

(c) (i) What is the colour change in the solution around electrode P?

...........................................................................................................................................
[1 mark ]
(ii) Describe a chemical test to determine the product formed in the solution at electrode P.

……………………………………………………………………………...................................

……………………………………………………………………………..................................
[2 marks ]
(d) What is the substance that is being oxidised in the experiment? Explain why.

…………………………………………………………………………………………............................

…………………………………………………………………………………………............................
[2 marks ]
(e) Write a half equation for the reaction that occurs at electrode Q.

.........…………………………………………………………………………………………....................
[1 mark ]
(f) Suggest another reagent that can replace chlorine water.

………………………………………………………………………………....................
[1 mark ]
(g) What is the change in oxidation number of chlorine in the reaction?

…………………………………………………………………………………………......
[1 mark ]


Chemistry Perfect Score Module 2010 Guidelines

Chemistry Perfect Score Module 2010 Guidelines

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Chemistry Perfect Score Module 2010 Guidelines