Answer 123

MARKING SCHEMEPAPER 1

1 C 21 A 41 A2 D 22 B 42 A3 A 23 C 43 B4 B 24 C 44 A5 B 25 A 45 D6 B 26 C 46 A7 D 27 C 47 D8 C 28 B 48 A9 A 29 B 49 C10 C 30 D 50 B

11 C 31 B12 A 32 B13 C 33 D14 B 34 C15 D 35 C16 D 36 C17 A 37 A18 D 38 B19 B 39 D20 B 40 A

PAPER 2

1 (a) (i) Sublimation/ diffusionR:solid to gas

1

(ii) Molecule 1(iii) I2 1(iv)

At least 9 particles [3×3] Same sizes Do not overlap

Solid state

// At least 3 particles Same sizes

Gaseous state

1

1

(b) (i) Higherr : faster 1

(ii) Iodine particles/ molecule absorb energy(heat)Kinetic energy of particles increase// Particles move faster

11

(c) (i) A process when particles of a substance/ gas P/Q move between the particles from high concentration to lower concentration. (hanya benar untuk gas sahaja)

1

(ii) Brown// light brown1

10

2 (a) (i) 22.34 Semua

betul – 2

2b - 1

(ii) 24.74(iii) 26.34

(b) (i) Mg = 24.74 – 22.34 // 2.4O = 26.34 – 24.74 // 1.6

11

(b) (ii) Mg : O 2.4 /24 : 1.6/16 // 0.1 : 0.1 // 1 : 1 1

(iii) Empirical formula = MgO 1(c) To allow the oxygen gas enter the crucible 1(d) 2Mg + O2 → 2MgO

1 - Correct formula2 - Balanced

11

(e) Cannot. Copper is less reactive than hydrogen gas // copper is placed below hydrogen in the reactivity series.

11

11

3 (a) (i) Cl 1 3(ii) Ne 1(iii) Al 1(iv) Ne, C, Cl, Al, Na 1

(b) (i) + -

1 – correct number of electrons in the shell2 – correct ratio of atoms, labelled nucleus and the charge of ions

Tanda + antara ion bagi 1+0

11

5

(ii) Ionic compound 1(iii) Electrostatic force 1(iv) High melting / boiling point // soluble in water // conduct

electricity in molten state and aqueous solution1

9

4 (a) blue 1(b) hydroxide ion // OH- , sulphate ion // SO4

2-

Ion hidroksida // OH- , ion sulfat // SO42-

1

(c) Zinc electrode // elektrod zink 1

(d) 4OH- O2 + 2H2O + 4e


11

(e) (i) Electrode that is connected to copper electrode // Reason : Anode is an electrode that is connected to positive terminal of chemical cell

11

Na

Cl

Elektrod yang disambungkan kepada elektrod kuprumAlasan : Anod adalah elektrod yang disambungkan kepada terminal positif sel kimia

(ii) The blue colour solution turns colourless // the intensity of blue colour decreases. The copper (II) ions in the electrolytes are selectively discharged to form copper atoms.Larutan biru menjadi tidak berwarna // keamatan warna biru semakin berkurangan.Ion-ion kuprum (II) dalam elektrolit dipilih untuk dinyahcas menjadi atom-atom kuprum.

1

1

(iii) Lighted splinter is placed into the test tube. A ‘pop’ sound is heard.Satu kayu uji bernyala dimasukkan dalam tabung uji. Satu bunyi ‘pop” kedengaran.

1

10

5 (a) CaCO3 + 2HCl CaCl2 + CO2 + H2O1 - Correct formula of product2 – Balanced

11

(b)

Volume of carbon dioxide gas // CO2

Isipadu karbon dioksida // CO2

1

(c) 60 // 60 // 20 cm3min-1 // 0.333 cm3s-1

3 3(60) Unit is compulsory

1

(d)

(i) Rate of reaction in set 2 is higher // vice versaKadar tindak balas di dalam set 2 lebih tinggi // sebaliknyaThe concentration of HCl in set 2 is higherKepekatan HCl di dalam set 2 lebih tinggi

1

1

(ii) A higher concentration of HCl , the higher is the number of particles in a unit volume. The frequency of collision between H+ and CO3

2- higher.The frequency of effective collision between particles higher.Semakin tinggi kepekatan HCl , semakin banyak bilangan zarah di dalam satu unit isipadu.Frekuensi perlanggaran antara H+ and CO3

2 meningkatFrekuensi perlanggaran berkesan antara zarah meningkat

11

1

(e)

1. Correct condition of value of volume and time2. Correct shape and gradient for both level curve

11

Total 11

6 (a) (i) Alkenes // Alkena 1(ii) CnH2n 1

(b) The number of carbon atoms per molecule increases. This increases the intermolecular attraction. The molecules will be more difficult to escape into the vapour state.Jisim molekul bertambah apabila bilangan atom karbon per molekul bertambah. Ini akan menambahkan tarikan antara molekul. Molekul- molekul akan lebih sukar untuk terbebas ke keadaan wap.

11

1

(c) C2H4 + H2O CH3CH2OH1 - Correct formula2 – Balanced

11

(d) H H H H

n C C C C

H H H H n 1.2.

11

Volume of CO2(cm3)Isipadu CO2(cm3)

Time / Masa (Min)

Set 2

Set 1

120

60

H H H

H C C C H

H

1

Total 10

7 (a) 1. Electron arrangement of atom A is 2.62. Atom A has 6 valence electron3. So, it is located in group 164. Atom A has 2 shells filled with electrons5. So it is located in Period 2

1111

1(b) (i) MgA 1

(ii) 2+ 2 -

1 – correct number of electrons in the shell2 – correct ratio of atoms, labelled nucleus and the charge of ionsTanda + antara ion bagi 1+0

11

(iii) 1. Magnesium atom has electron arrangement 2.8.2 with 2 valence electrons

2. Magnesium atom release 2 electrons to achieve the stable octet arrangement

3. A positive ion, Mg2+ is formed4. Atom A has electron arrangement of 2.6 with 6 valence

electrons5. Atom A receives 2 electrons from magnesium atom to

achieve the stable octet arrangement6. A negative ion, A2- is formed7. A magnesium ion and an A2- ion are attracted together

by strong electrostatic forces

1

1

11

1

11

7( c)

1. Diagram shows correct sharing of electrons between two A atoms and one C atom.

2. Correct number of electrons in each shell

1

1 2

Mg

O

C AA

(d) 1. Compound in 7(b) has high melting point whereas compound in 7(c) has low melting point

2. Compound in 7(b) consist of positive and negative ions which are held together by strong electrostatic forces.

3. Compound in 7(c) consist of molecules which are held together by weak ‘Van der Waals’ forces. So, less energy is required to overcome these forces

1

1

1

3

8 (a) A mixture of two or more elements where the major component is a metal

11

(b) 1. Improve the appearance2. Improve the strength and hardness3. Increase the resistance to corrosion[ Any two correct ]

11

2(c) (i) 1. Pure copper is made up of same type of atoms and are

of same size.2. The atoms are arranged in an orderly manner3. The layer of atoms can slide over each other4. Bronze is made up of atoms of different size5. The atoms are not orderly arranged// The presence of

tin atoms disturb the orderly arrangement of copper atoms

6. This reduces/prevents the layer of copper atoms from sliding

1

1111

1Max

5(ii)

At least 9 particles [3×3] Same sizes Do not overlap

Pure copper Copper

Tin

Bronze1. Present of foreign atom (different size)2. label

1

11 3

(d) DuraluminReason :1. Its stronger/harder2. Can withstand compression3. Lighter (Any

1

12

two)(e) (i) 1. Sulfur trioxide is dissolved in concentrated sulphuric

acid to form oleum.2. Oleum is diluted with water to produce sulphuric acid.

1

1 2(ii) I : SO3 + H2SO4 H2S2O7

II : H2S2O7 + H2O 2H2SO4

11 2

(iii) n = 48 // 1.5 32 S + O2 SO2

1 mol S1 mol SO2

1.5 mol S 1.5 mol SO2

Volume SO2 = 1.5 x 24 // 36 dm3

1

11 3

9 (a) You are required to calculate the mass of sodium hydroxide which reacts

Completely with reacts completely with 50 cm3 of 0.1 mol dm-3 of ethanoic acid.

Answer:

CH3COOH + NaOH CH3COONa + H2O

n = 0.1X 50 // 0.005 mole

1000

1 mol of ethanoic acid reacts with 1 mol of NaOH

0.005 mol of ethanoic acid reacts with 0.005 mol of NaOH

Value of X = 0.005(23+16+1) // 0.2 g

1

1

1

1 4

(b) (i) You are required to name solvent L and M.

Answer:

Solvent L is water.

M is methylbenzene // tetrachloromethane (propanone can also be used)

1

1

(ii) Acid dissolve in water to produce Hydrogen ion, H+. 1

When zinc reacts with H+, hydrogen gas is release.

Without water i.e in methylbenzene, an acid is still exists as molecules // no hydrogen ion (H+) present.

1

1

6

(iii) Zn + HCl ZnCl2 + H2 //

Zn + 2H+ Zn2+ + H2 1

(c ) You are required to describe the confirmatory tests to determine the presence of cation and anions.

Answers:

(I) Confirmatory test for nitrate (NO3- anion): Brown

ring test

1. Pour about 2 cm3 of the mixture into the test tube.

2. Add 2 cm3 dilute sulphuric acid

3. followed by 2 cm3 of iron(II) sulphate solution and shake well.

3. Concentrated sulphuric acid is added slowly down / drop by drop the side of the test tube by using a dropper.

4. A brown ring formed shows the present of NO3-.

(II) Confirmatory test for chloride ion (Cl- anion):

1. Pour about 2 cm3 of the mixture into a test tube.

2. Add nitric acid / HNO3

3. followed by silver nitrate solution / lead (II) nitrate solution.

4. A white precipitate is formed show the presence of chloride ions.

1

1

1

1

1

1

1

1

(III) Test for iron(III) (Fe3+ cation)

1. Pour about 2 cm3 of the mixture into a test tube.

2. followed by potassium hexacyanoferrate(II) / K4Fe(CN)6 solution.

3. A dark blue precipitate is formed shows the presence of iron(III) ions.

1

1 10

10 (a) (i) You are required to suggest one possible cation for X 2+ in XY2. This compound must be a soluble salt.

Cu2+ / Zn2+ / Pb2+ / Mg2+

Cu2+ + 2e Cu // 2H+ H2 + e


1

11

3

(ii) Reduction / receive electron

Penurunan // menerima elektron

1

(b) Copper(II) nitrat and copper(II) chloride are soluble salt that have similar formula XY2.

1. If Y- is nitrate, hydroxide ions will be selectively discharge:

2. Oxygen gas is released.

3. OH- is selected for discharge because OH-is lower than NO3

- in electrochemical series.

40H- O2 + H2O + 4e

Chemical test/ujian kimia:

4. Place a glowing splinter into the test tube.

Masukkan kayu uji berbara dalam tabung uji

5. The splinter relights / rekindles / light up

Kayu uji berbara itu menyala semual menunjukkan gas itu adalah oksigen

1

1

1

1

1

1

6

atau

1. If Y- is chloride, chloride ions will be selectively discharged:

2. Chlorine gas is released

3. Cl- is selected for discharge

4. Because concentration of Cl- is higher.

2Cl- Cl2 + 2e

5. Moist blue litmus paper is put in the test tube.

6. Moist blue litmus paper turns red and bleaches / decolourised

1

1

1

1

1

1

Atau

6

(c) A silver plate and iron spoon have to place at the anode and cathode respectively for electroplating. Include a suitable electrolyte in the materials and list all the apparatus needed. Give the complete procedure and labelled diagram in your description.

Answer:

Material and apparatus/bahan dan radas:

Iron spoon, silver plate, wire, batteries, beaker, silver nitrate solution

Sudu besi, kepingan argentum, wayar, bateri, bikar, larutan argentum nitrat.

Procedure:

1. The iron spoon is cleaned with sandpaper

Sudu besi dibersihkan dengan menggunakan kertas pasir.

2. Silver nitrate solution is poured into a beaker until half full.

Larutan argentum nitrate dituangkan ke dalam sebuah bikar.

4. A silver plate used as anode and an iron spoon are

1

1

1

1

cathode respectively.

Satu kepingan argentum dan satu sudu besi masing-masing digunakan sebagai anod dan katod.

4. Both electrodes are immersed in the solution.

Kedua-dua elektrod direndamkan dalam larutan.

5. The switch is turn on // complete the circuit

Hidupkan suis untuk melengkapkan litar.

Gambarajah berlabel / Labelled diagram:

6. Functional diagram

7. Label

8. half equation / Setengah persamaan:/

Anod / Anode :

Ag Ag+ + e

Cathode / Katod:

Ag+ + e Ag

1

1

1

1

1

1 10

MARKING SCHEME OF PAPER 3 (4541/3)

Question Rubric Score

1( a)(i) [Able to state the observation correctly ]

Sample answer:

A yellow precipitate is formed

3

[Able to state the observation less correctly]

Sample answer:

Precipitation occur

2

[Able to state an idea of the observation]

Sample answer:

Change of colour

1

[ No response or wrong response] 0


1(a)(ii) [Able to state the inference correctly]

Sample answer:

Sulphur is formed

3

[Able to state the inference less correctly]

Sample answer:

Precipitate is formed.

2

[Able to state an idea of the inference]

Sample answer:

Change of colour

1

[No response or wrong response] 0


1(b) [Able to state three variables correctly]

Sample answer:

Manipulated variable: Concentration of sodium thiosulphate solution

Responding variable: rate of reaction

Constant variable: Temperature of sodium thiosulphate solution// concentration and volume of hydrochloric acid

3

[Able to state any two variables correctly ] 2

[Able to state any one variable correctly ] 1



1(c) [Able to state the relationship between the manipulated variable and the responding variable with direction correctly]

Sample answer:

The higher the concentration of sodium thiosulphate solution, the higher the rate of reaction.

3

Able to state the relationship between the manipulated variable and responding variable

Sample answer:

The shorter the time taken, the higher the rate of reaction. 2

[Able to state the idea of hypothesis]

Sample answer:

Different concentration produce different rate of reaction 1



1(d) [Able to state the operational definition for rate of reaction correctly ]

Sample answer:

When time taken for ‘X’ mark to disappear is shorter, the concentration of sodium thiosulphate solution is higher.

3

[Able to state the operational definition less accurately]

Sample answer: 2

[Able to state an idea of the operational definition]

Sample answer: 1

[ No response or wrong response] 0


1(e) (i)

[Able to record all readings accurately to two decimal point with unit]

Sample answer:

Set I II III IV

Concentration of sodium

thiosulphate solution (mol

dm-3)

0.20 0.16 0.12 0.18

Time (s) 20 25 33 50

1/time (s-1) 0.05 0.04 0.03 0.02

3

[Able to record all readings accurately with correct decimal point or unit ]

readings to one decimal point without unit readings to two decimal point with unit 2

[Able to record three to five readings correctly] 1

[No response given or wrong response] 0


1(e)(ii) [Able to draw the graph correctly]

1. Axis x : 1/time (s-1)and axis y : concentration of sodium thiosulphate solution (mol dm-3)

2. Consistent scale and the graph is half from the graph paper

3. All points are transferred correctly

4. CurveSample answer:

3

[Able to draw the graph incorrectly]

1. Axis x : 1/time and axis y : concentration of sodium thiosulphate solution

2. Consistent scale and the graph is half from the graph paper

3. Three points are transferred correctly

4. Curve

2

[Able to state an idea to draw the graph]

1. Axis x and axis y

2. Curve

1



1(f)(i) [Able to state the relationship accurately]

Sample answer:

The higher the concentration of sodium thiosulphate solution, the higher the rate of reaction.

3

[Able to state the relationship less accurately]

Sample answer:

Different concentration produce different rate of reaction

2

[Able to state an idea of the relationship]

Sample answer:

Concentration affect rate of reaction

1



1(f)(ii) [Able to draw a line on the graph and state the time]

Sample answer:

3

[Able to draw a line on the graph or state the time] 2

[Able to state an idea to mark the time ] 1



1(g)

[Able to give all three explanations correctly]

Sample answers: 3

[Able to give any two explanations correctly] 2

[Able to give any one explanations correctly] 1



1(h) [Able to classify all the four ions correctly]

Sample answer:

Anions Cations

Cl- H+

S2O32- Na+

3

[Able to classify any two ions correctly] 2

[Able to classify any two materials correctly]

if reverse score 1

Sample answer:

Anions Cations

H+ Cl-

Na+ S2O32-

1



2(a) To investigate the effect of alloying a on the hardness of copper // To investigate the hardness of copper and bronze

3

To investigate the effect of alloying on the hardness of metal // To investigate the hardness of copper/bronze

2

To investigate the effect of alloying // Problem statement is given as answer

1

Wrong respond or no respond 0


2(b) Manipulated variable: Copper and bronze //Different type of materialResponding Variable: Diameter of dentFixed Variable: Diameter / size of steel ball bearing // height of the weight // mass of the weight

3

Any two variables correct or variables with less accurateExample : Manipulated variable : metal and alloy

2

Any one variable correct 1Wrong respond or no respond 0


2(c) Bronze is harder than copper 3Alloy is harder than metal // Bronze is harder // Copper is less harder 2Alloy is harder // metal is less harder 1wrong respond 0


2(d) Material : Copper block, bronze block, cellophane tapeApparatus : Retort stand and clamp, one kilogram weight, Steel ball bearing, metre rule, thread

3

Material: copper block, bronze blockApparatus: Weight, ball bearing, metre rule

2

Have idea Material : Metal and alloyApparatus : Weight, ball bearing

1

wrong respond or no respond 0


2(e) 1. Steel ball bearing is stick onto the copper block by using a cellophane tape.// Steel ball bearing is tape on to the copper block.

2. A 1 kg weight is hang at a height of 50 cm above the ball bearing.3. A weight is drop onto the ball bearing.4. The diameter of the dent made on the copper block is measured

and recorded.5. Step 1 to 4 is repeated twice.6. The experiment is repeated by using bronze block.

3

Step 1,3,4,6 less accurate.1. ASteel ball bearing is put onto the copper block.2. A weight is drop onto the ball bearing.3. The diameter of the dent is measured and recorded.4. The experiment is repeated by using bronze block.

2

Step 1,3,4 1wrong respond or no respond 0


2(f) Correct table with complete rows and column1. Correct titles with unit2. Complete list of materialType of block

Diameter of dent / cm Average / cm

1 2 3CopperBronze

Note: If no step 5 in d) accept 1 column of diameter

Type of block Diameter of the dent / cm

CopperBronze

2

Incomplete table: titles with incomplete material or incomplete title with complete material

Diameter CopperBronze

1

Type of block Diameter / cmCopper /bronze

Wrong respond or no respond 0

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Answer 123