chemistry trial-exam spm 2012 marking scheme paper · pdf file1 . bahagian pengurusan sekolah...

1

BAHAGIAN PENGURUSAN SEKOLAH BERASRAMA PENUH

DAN SEKOLAH KECEMERLANGAN

KEMENTERIAN PELAJARAN MALAYSIA

CHEMISTRY

TRIAL-EXAM

SPM 2012

MARKING SCHEME

PAPER 1

PAPER 2

PAPER 3

ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum

a) skema lain di : M

uat turun (percuma) skem

a lain di

2

SKEMA KERTAS 1

PENTAKSIRAN DIAGNOSTIK AKADEMIK

SBP 2012

CHEMISTRY 4541/1

1 A 26 C

2 A 27 D

3 C 28 C

4 A 29 D

5 A 30 B

6 D 31 B

7 B 32 C

8 A 33 A

9 B 34 C

10 A 35 C

11 B 36 D

12 A 37 A

13 D 38 B

14 C 39 B

15 D 40 D

16 A 41 D

17 B 42 D

18 D 43 A

19 C 44 B

20 B 45 C

21 C 46 B

22 D 47 C

23 D 48 B

24 B 49 D

25 A 50 C

ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain di

3

MARKING SCHEME

CHEMISTRY PAPER 2 SECTION A (4541/2)

Question Mark scheme Sub

Mark

Total

Mark

1(a) A: Detergents

B: Soap

r : sodium salt

1

1

2

1(b)(i) magnesium ion // or calcium ion

r : Mg2+

, Ca2+

1

2 1(b)(ii) Soaps are biodegradable 1

1(c) Analgesics

Psychotherapeutic

r: wrong spelling

1

1

2

1(d)(i) Sugar

Aspartame

1

1

3

1(d)(ii) To add / restore the colour of food // To enhance its visual

appeal / appearance// more attractive

1

TOTAL 9


Mark

Total

Mark

2(a)(i) Magnesium

r:Mg 1

2

2(a)(ii) Has 3 shell occupied with electrons 1

2 (b)

1. Proton number of chlorine is higher than magnesium // the

number of proton of chlorine atom higher than magnesium atom

// total positive charged in nucleus higher than magnesium

2. The attractive force between the nucleus and the electrons in

chlorine atom stronger than magnesium atom // nuclei attraction

towards electrons stronger.

1

1

2

2(c) Light bulb // in welding process 1 1

2 (d) Argon 1 1

2(e)(i)

3 Cl2 (g) + 2 Fe (s) 2 FeCl3(s)

1

1

2(e)(ii) Mass iron (III) chloride = 0.05 x 161 // 8.05 g 1 1

ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain diM


a lain di : Muat turun (percum

a) skema lain di

ww

w.m

yschoolchildren.com

4

2(e)(ii)

1

1

Total 9


Mark

Total

Mark

3(a)(i) 6 1

4

3(a)(ii) To estimate the age of fossils and artifacts 1

3(a)(iii) C-12 // C-13

1

3(a)(iv) 7 / 6 1

3(b)(i) A: covalent

r: covalent bond

B: ionic

r: ionic bond

1

1

6

3(b)(ii) 2.8.8.1 1

3(b)(iii) High melting point and boiling point // conduct electricity in

molten or aqueous solution // soluble in water // insoluble in

organic solvent.

[Any one]

1

3(c)(iv) 2K + Cl2 2KCl

1. Formula of reactants and products correct

2. Balance the chemical equation

1

1

TOTAL 10

13

C 6

12

C 6

Or

Hot iron wool

Wul besi panas

Heat

Panaskan

Chlorine gas

Gas klorin

√

ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain di

5


Mark

Total

Mark

4(a)(i) Pipette

r: wrong spelling 1

3

4(a)(ii) Phenolphthalein // methyl orange

r: wrong spelling 1

4(a)(iii)

Phenolphthalein : pink to colourless //

methyl orange : yellow to orange

1

4(b)(i)

2KOH + H2 SO4 K2 SO4 + 2H2O

Formula of reactants and products correct

Balance the chemical equation

1

1

2

4(b)(ii)

1. Mol of KOH = (1.0)(25) / 1000

= 0.025 mol

2. Molarity of H2 SO4 = (0.0125)(1000) / 10

= 1.25 mol dm-3

//

Molarity of H2SO4 = 0.0125 /0.01 = 1.25 mol dm-3

Or

b

a

VM

VM

bb

aa ; Molarity of H2SO4 = 10

)25(1

2

1x

= 1.25 mol dm-3

r: wrong unit or without unit

1

1

2

4(c)(i) Hydrogen ion

r: H+ (symbol ion)

1

3 4(c)(ii)

1. no water

2. contain of molecule // no hydrogen ion, H+

1

1

TOTAL 10

ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain diM



a) skema lain di

6


Mark

Total

Mark

5(a) Chemical formula that shows the simplest whole number ratio of

atom of each element in the compound.

1 1

5(b)(i) Mass of Mg = 2.4 g

Mass of O = 1.6 g

1

6

5(b)(ii) Mole of Mg = 2.4 / 24 = 0.1

Mol of O = 1.6 / 16 = 0.1

Mg : O = 1 : 1

1

1

5(b)(iii) MgO 1

5(b)(iv) to allow oxygen enter the crucible 1

5(b)(v) Repeat the process heating, cooling and weighing until a

constant mass is obtained.

1

5(c)

Apparatus set-up correct and functional

Labeled : magnesium ribbon, heat

1

1

2

5(d)(i) Zinc oxide // aluminium oxide

r: formula

1

2

5(d)(ii) Silver is less reactive / not reactive metal 1

TOTAL 11

Magnesium

ribbon

Heat

crucible

ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain diM



a) skema lain di

7


Mark

Total

Mark

6(a) Hydrogenation 1

5

6(b) C4H8 + H2 C4H10 1

6(c)(i)

Mole of butene = 2.8 /56 = 0.05 mol

1

6(c)(ii) P1. 1 mol of butene burns in oxygen gas produce 4 mol of

carbon dioxide.

Therefore 0.05 mol of butene burns in oxygen gas produce 0.2

mol of carbon dioxide //

C4H8 : CO2

1 : 4

0.05 : 0.2

P2. volume of CO2 = 0.2 x 24 = 4.8 dm3

1

1

6(d) P1: 2 cm3 of but-2-ene and 2 cm

3 of butane gas are filled in two

different test tubes.

P2 : 2 -3 drops of acidified potassium manganate (VII) solution

is added to both test tubes.

P3: But-2-ene decolourises purple acidified KMnO4

Purple acidified KMnO4 in butane remains unchange.

Or

P1: 2 cm3 of but-2-ene and 2 cm

3 of butane gas are filled in two

different test tubes.

P2 : 2-3 drops of bromine water is added to both test tubes.

P3: But-2-ene decolourises brown bromine water.

Brown bromine water in butane remains unchange.

1

1

1

Or

1

1

1

3

6(e)(i) A: unvulcanised rubber

B: vulcanised rubber

1

1

3

6(e)(ii) Rubber type B/ vulcanised rubber is more elastic than rubber

type A/ unvulcanised rubber

1

TOTAL 11

ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain diM



a) skema lain di

8

SECTION B

Question Mark scheme Mark Σ

Mark

7 (a)

(i) Ascending order : Cu, Y,X, W

(ii)

P1 : Positive terminal : Cu

P2 : Potential difference : 1.3V

P3: Copper is less electropositive // X is more electropositive

correct value and unit

1

1

1

1

4

7 ( b) (i)

Experiment I : Pb 2+

, Cl-

Experiment II: H +

. OH- , Cl

–

r: lead(II) ion, chloride ion

Hydrogen ion, hydroxide ion, chloride ion

1

1

2

7(b)(ii)

Experiment 1 Experiment II

Product at anode:

Chlorine gas

Products at cathode:

Oxygen gas

Reason:

P1: Cl-

is discharged

P2: the only

anion presence

and discharged at anode

Reason:

P1:OH- is selected to be

discharged

P2:the position of OH- is lower

than Cl- in electrochemical series

.Half equation:

2Cl-

Cl 2 + 2e

P1:Correct formula of

reactant and product :

P2: Balance equation

. Half equation:

4OH- 2 H2O + O2 + 4e

P1: Correct formula of reactant

and product

P2: Balance equation

1 + 1

1 + 1

1 + 1

1 + 1

1 + 1

10

ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain di

ww

w.m

yschoolchildren.com

9

7(c)

P1: Positive terminal: R

P2: Negative terminal:Cu

P3: Suitable metal for R : Silver

P4: Suitable solution for R : Silver nitate solution

1

1

1

1

4

Total 20

Question Mark scheme Mark Σ Mark

8(a) P1. Smaller size has larger total surface area.

P2. Absorb heat faster.

P3. Bigger size has smaller total surface area.

P4. Absorb heat slower

1

1

1

1

4

(b)(i) Copper(II) sulphate 1 1

(b)(ii) 1. Experiment I

Rate of reaction = 40/2 = 20 cm3 min

-1

2. Experiment II

Rate of reaction = 60/2 = 30 cm3min

-1

1

1

2

(b)(iii) P1. Rate of reaction in Experiment II is higher than

Experiment I.

P2. Substance X used in Experiment II is a catalyst.

P3. Catalyst provided an alternative path with requires a

lower

activation energy.

P4. More particles are able to achieve lower activation

energy.

P5. Frequency of effective collisions between zinc atoms and

hydrogen ions are higher.

1

1

1

1

1

5

ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain diM



a) skema lain di

Muat turun (percum



a lain di

10

(b)(iv) 1. Label of axes and unit

2. Correct curve and label

1

1

2

(v) 1. Correct formula of reactants and product

2. Balanced equation

Zn + 2H+ Zn

2+ + H2

1

1

2

(vi) 1. Rate of reaction using sulphuric acid is higher.

2. Volume of hydrogen gas released is doubled.

3. Sulphuric acid is a diprotic acid.

4. Concentration of hydrogen ions in sulphuric acid is double

than that in hydrochloric acid.

1

1

1

1

4

Total 20

Volume of

gas / cm3

Time / min

Exp II

Exp I

2

ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain di

11


Mark

9(a) P1: Magnesium atom undergoes oxidation

P2: oxidation number increases from 0 to 2+

P3: Copper (II) ion undergoes reduction

P4: oxidation number decreases from +2 to 0

P5: The reaction involving oxidation and reduction

1

1

1

1

1

MAX

4

(b) Experiment I

L can reduce copper(II) oxide// L can react with copper(II) oxide

L is more reactive than copper.

Experiment II

M can reduce copper(II) oxide//M can react with copper(II)

oxide

M is more reactive than copper.

Experiment III

M cannot reduce L oxide // M cannot react with L oxide.

M is less reactive than L//L is more reactive than M.

The arrangement in order of increasing reactivity toward oxygen is Cu,

M and L.

1

1

1

1

1

1

Max

5

1

6

(c)

Procedure :

P1. Pour 2 cm3 of potassium bromide solution into a test tube.

P2. Add 2 cm3 of chlorine water to the test tube and shake the mixture.

P3. Add 2 cm3 of 1,1,1 trichloroethane to the test tube and shake the

mixture.

P4. Record the observation

P5. Repeat steps 1-4 using another halogens and halide solution.

.

1

1

1

1

1

ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain diM



a) skema lain di

12

Result :

Chlorine water Bromine water Iodine water

Potassium

chloride

X X

Potassium

bromide X

Potassium

iodide

Ionic equation:

1. Cl2 + 2Br- 2Cl

- + Br2

2. Cl2 + 2I- 2Cl

- + I2

3. Br2 + 2I- 2Br

- + I2

1

1

1

1

1

10

20

ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain diM



a) skema lain di

13


Mark

10(a)

Precipitation / double decomposition reaction

Barium nitrate solution/barium chloride solution

[Any sulphate solution]

Example: sodium sulphate, potasium sulphate, sulphuric

acid

Reject : Lead(II) sulphate, calcium sulphate

Ba2+

+ SO42 BaSO4

1

1

1

1

4

10(b)(i) Cation : Iron(II) ion / Fe

2+

Anion: Chloride ion / Cl

1

1

2

10(b)(ii)

Test for NO3

P1: Add 2 cm3

of dilute sulphuric acid into the test tube follow

by 2 cm3 of iron(II) sulphate solution.

P2: Add a few drops of concentrated sulphuric acid

P3: carefully and slowly along the side of slanting test tube

into the mixture.

P2: A brown ring is formed.

1

1

1

1

4

10(c)

Procedure:

P1. Add zinc nitrate solution to sodium carbonate solution

in a beaker.

P2. Stir the mixture.

P3. Filter the white precipitate/solid zinc carbonate formed.

P4. Add zinc carbonate to sulphuric acid in a beaker until

some zinc carbonate solid no longer dissolve.

P5. Filter the mixture.

P6. Transfer the filtrate to a evaporating dish.

P7. Heat the filtrate(zinc sulphate solution) until saturated//

Heat the filtrate to about one-third (1/3) of its initial

volume

P8. Allow the saturated solution to cool at room temperature.

P9. Filter the crystals formed.

P10. Dry the crystals by pressing it between two sheets of

filter papers.

1

1

1

1

1

1

1

1

1

1

10

Total 20

ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain diM



a) skema lain di

ww

w.m

yschoolchildren.com

1

Marking Scheme Chemistry Paper 3

[KK0503 – Mengukur menggunakan nombor]

[KK0506 – Berkomunikasi]

Question Rubric Score

1(b)

Able to construct the table with correct label and unit

Sample answer:

Type of

blocks

Diameter of dents(cm) Average diameter

of dents (cm) I II III

Copper 1.35 1.60 1.50 1.48

Bronze 1.20 1.00 1.20 1.13

3

Able to construct the table without correct label or unit 2

Able to construct the idea of table 1

No response or wrong response 0

[KK0501 – Memerhati]


1(c) (i)

Able to state the observation correctly and accurately

Sample answer:

The average diameter of dents on bronze block is 1.13 cm, the

average diameter of dents on copper block is 1.48 cm.//

The size / diameter of dents on bronze block is smaller than the size

/ diameter of dents on copper block//

The size / diameter of dents on copper block is bigger than the size /

diameter of dents on bronze block

3

Able to state the incomplete observation

Sample answer:

Able to state the average diameter of one block only.

The size / diameter of dents on bronze block is smaller//

The size / diameter of dents on copper block is bigger.

2

Able to state the idea of observation

Sample answer :

The size / diameter of dents on bronze block is small/

The size / diameter of dents on copper block is big.

1



1(a)

Able to measure the diameter of dents correctly and accurately

Sample answer:

Copper: 1.35, 1.60, 1.50

Bronze: 1.20, 1.00, 1.20

3

Able to measure the diameter of dents without 2 decimal point 2

Able to state 4 diameter of dents correctly 1


ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain di

2

[KK 0504 – Membuat Inferens]


1(c)(ii)

Able to state the inference correctly and accurately

Sample answer:

Bronze is harder than copper //

Copper is less harder than bronze

3

Able to state the incomplete inference correctly

Sample answer :

Bronze is harder //

Copper is less harder

2

Able to state the idea of inference

Sample answer :

Bronze is hard//

Copper is soft

1


[KK0508 – Mentafsir data]


1(c)(iii)

Able to explain the arrangement of particles in the materials

correctly

Sample answer:

1. The atomic size of tin is bigger than copper// The atomic size of

tin and copper are different

2. The presence of tin atoms in bronze disrupts the orderly

arrangement of copper atoms

3. Reduces/ Prevent the layers of atoms from sliding over each

other/ easily.

3

Able to state any 2 points // 3 points without the name of atoms

correctly

2

Able to state point 1 point correctly 1


[KK0510 – Mengawal pemboleh ubah]


1(d)

Able to state all the variables

Sample answer:

Manipulated variable : Type of materials / blocks//

Copper and bronze

Responding variable : Size / diameter of dents

Fixed variable : Size / diameter and mass of steel ball bearing //

height of the weight // mass of the weight

3

Able to state two variables correctly 2

Able to state one variable correctly 1


ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain diM



a) skema lain di

Muat turun (percum



a lain di

3

[KK0511 – Membuat hipotesis]


1(e)(i)

Able to state the hypothesis correctly

Sample answer:

Bronze is harder than copper //

Copper is less harder than bronze

3

Able to state the hypothesis less correctly 2

Able to state idea of hypothesis 1


[KK0509 – Mendefinisikan secara operasi]


1(e)(ii)

Able to state the operational definition correctly

Sample answer:

The smaller dent produced when a 1 kg weight is dropped on the

block.

3

Able to state the operational definition less correctly The smaller dent produced when a weight is dropped on the block//

When a weight is dropped on the block results smaller dent, thus the

harder the block is.

2

Able to state idea of operational definition The harder block has a smaller dent.

1


[KK0502 – Mengelas]


1(e)(ii)

Able to classify all substances correctly

Sample answer:

Alloy Pure metal

Steel

Brass

Pewter

Iron

Chromium

Tin

3

Able to classify at least 4 substances less correctly

Sample answer:

Alloy Pure metal

Steel

Brass

Tin

Iron

Chromium

Pewter

2

Able to state idea of classification (at least 2 correct)

Sample answer :

Alloy Pure metal

Iron

Chromium

Pewter

Steel

Brass

Tin

1


ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain di

4

[KK0505 – Meramal]


2(a)

1. Able to show an extrapolation on the graph .

Sample answer:

2. Range of answer[ 2600 - 2700 ]

3. Show the negative sign and correct unit, kJmol-1

3

Able to state any two correct answers

2

Able to state any one correct answer

1


[KK0507 – Menggunakan perhubungan ruang dan masa]


2(b)

Able to state the relationship between the number of carbon atom

per molecule and the time taken for cooking correctly

Sample answer

The higher the number of carbon atom per molecule alcohol, the

shorter the time taken for cooking

3

Able to state the relationship between the number of carbon atom

per molecule and the time taken for cooking less correctly

Sample answer

The higher the number of carbon atom, the shorter the time taken

for cooking

2

Able to give relevant idea 1


Number of carbon atom per molecule of alcohols

Heat of combustion/ kJ mol-1

Haba pembakaran/ kJ mol-1

5

0

0

0 1 2 3 4

500

1000

1500

2000

2500

3000

3500

ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain diM



a) skema lain di

5

[KK0512 –Menyatakan masalah]


3(a)

Able to give the problem statement correctly

Sample answer:

How does different type of metals in contact with iron affect

rusting?//

Does more electropositive metal in contact with iron inhibit the

rusting of iron?//

Does less electropositive metal in contact with iron speed up the

rusting of iron?

3

Able to give the problem statement less correctly

To investigate the affect of other metals on the rusting of iron//

How does a metal affect the rusting of iron?

2

Able to state an idea of hypothesis

More electropositive metal inhibit the rusting of iron//

Less electropositive metal speed up the rusting of iron

1

No response or wrong response

0

KK0512 – Menyatakan pemboleh ubah]

Question Rubric Marks

3(b)

Able to state all the three variables correctly

Manipulated variable :

Name of metal R and metal S// type of metals

Responding variable :

Rusting of iron//iron rust//formation of blue spot

Constant variables:

Iron nail//Gelatine solution with potassium

hexacyanoferrate(III) and phenolpthtalein

3

Able to state any two variables correctly 2

Able to state any one variable correctly 1

No response or wrong response

0

ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain diM



a) skema lain di

ww

w.m

yschoolchildren.com

6

[KK0512 – Menulis hipotesis]

Question

Rubric Marks

3(c) Able to state the relationship between the manipulated variable

and the responding variable and state the direction.

Sample answer:

When a more electropositive metal is in contact with iron,

the metal inhibits rusting. // When a less electropositive

metal is in contact with iron, the metal speed up rusting

3

Able to state the relationship between the manipulated variable

and the responding variable less correctly

Sample answer:

A more electropositive metal will prevent iron from

rusting. // A less electropositive metal will cause iron to

rust.

2

Able to state an idea of hypothesis

Sample answer:

Metal R and metal S affect rusting (of iron)

1


[KK0512 – Menyenaraikan bahan dan radas]

Question Rubric Mark

3 (d) Able to give complete list of substances and apparatus

Answer:

Substances

Two Iron nails,

Magnesium/zinc/aluminium strip

Tin/copper/lead/silver strip

Potassium hexacyanoferrate(III) solution +

phenolphthalein

[Any suitable electrolyte]/[water]

Apparatus

Test tube/boiling tube

Test tube rack

Sand paper

3

Able to list basic materials and apparatus

Sample answer:

Materials

Magnesium/zinc/aluminium strip

Tin/copper/lead/silver strip

Iron nail

Any suitable electrolyte

2

ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain diM



a) skema lain di

7

Apparatus:

Any suitable container

Able to give an idea of the materials and apparatus

Sample answer:

Materials

Iron

Any electrolyte

Apparatus

Any suitable container

1


[KK0512 – Memilih teknik]


3 (e)

Able to state all the steps correctly

Sample answer:

1. Clean the iron nails and metals strip with sand paper.

2. Coil iron nails with magnesium ribbon and copper strip.

3. Put the coiled iron nail into different test tubes.

4. Pour the hot jelly solution containing potassium

hexacyanoferrate(III)solution and phenolphthalein into

the test tube.

5. Leave the test tube in a test tube rack for a day.

6. Record the observation.

3

Able to state the steps 2,4,and 6 correctly 2

Able to state steps 2 and 4 correctly

[2 and 4 ]//the idea combining iron and any metals and any

substances

1


ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain di

8

[KK0512 – Mempamerkan perancangan]


3 (f) Able to tabulate the data with the following aspects

1. Heading for the manipulated variables

[pair of metals//Test Tube]

2. Heading for responding variables

Sample answer:

Pair of metals Observation

Mg/Fe

Cu/Fe

2

Able to give an idea on tabulation of data at least one

information stated in the table

1. At least one heading

Sample answer

Set

1


PERATURAN PEMARKAHAN TAMAT

ww

w.m

yscho

olch

ildren

.com

ww

w.m

yscho

olch

ildren

.com

Muat turun (percum



a lain diM



a) skema lain di

Muat turun (percum



a lain di

chemistry trial-exam spm 2012 marking scheme paper · pdf file1 . bahagian pengurusan sekolah...

Documents