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
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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
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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
Question Mark scheme Sub
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
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2(e)(ii)
1
1
Total 9
Question Mark scheme Sub
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
5
Question Mark scheme Sub
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
6
Question Mark scheme Sub
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
= 2 x 24 = 48 dm
0.5 : 2
ole of butene = 28 /56 = 0.5 mol
Hydrogenation // Addition with hydrogen
7
Question Mark scheme Sub
Mark
Total
Mark
6(a) 1
5
6(b) C4H8 + H2 C4H10 1
6(c)(i)
M
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
P2. volume of CO2 3
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
8
SECTION B
Question Mark scheme Mark
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
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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 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
10
(b)(iv) 1. Label of axes and unit
2. Correc
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