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PERATURAN PEMARKAHANKIMIA KERTAS 2

MODUL PENINGKATAN PRESTASI 2014SEKOLAH-SEKOLAH MENENGAH ZON B KUCHING

SECTION A

No Answer SubMark

TotalMark

1 (a) R: 2.6; S: 2.8.3 1+1 2

(b) 27-13// 14 1 1

(c) Q and R 1 1

(d) Group 1 and Period 4 1 1

(e) P and T 1 1

(f)(i) Ionic bond 1 1

(ii) S2Q3 1 1

(iii) state any one of physical properties of ionic compounds.

ex: high melting and boiling points; soluble in water but insoluble in organic

solvents

1 1

TOTAL 9

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2 (a) to dry the hydrogen gas 1 1

(b)(i) to avoid oxygen in air react with hydrogen gas//to prevent explosion 1 1

(ii) to prevent the hot copper react with oxygen in the combustion tube from

reform copper(II) oxide1

1

(c)

Element Cu O

Mass (g) 3.2 0.8

Number of mole 3.2/64 = 0.05 0.8/16 = 0.05

Mole ratio 1 1

Empirical formula : CuO

1

1

1 3

(d)

CuO + H2 Cu + H2O

(correct chemical formulae of reactants and products – 1M)

(correct balance chemical equation – 1M)

1+1 2

(e) The heating, cooling and weighing processes are repeated until a constant

value is obtained1

1

TOTAL 9

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3 (a)(i) Cu2+, H+ 1

2(ii) 24SO , OH- 1

(b)(i) Cu Cu2+ + 2e- 1 1

(ii) Cu2+ + 2e- Cu 1 1

(c)(i) Remain unchanged 1 1

(ii) The rate of dissociation/ionization of Cu2+ ions at anode is the same as the

rate of discharged of Cu2+ at the cathode

1 1

(d)(i) Oxygen gas 1 1

(ii) Copper metal 1 1

(iii) Insert a glowing splinter into the test tube containing the gas.

The glowing splinter will be rekindled / relighted.

1

1

1

1

TOTAL 10

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4 (a)

Mg + 2HCl → MgCl2+ H2

(correct chemical formulae of reactants and products – 1M)

(correct balance chemical equation – 1M)

1+1 2

(b) Size of particle//magnesium//total surface area

Concentration of hydrogen ion, H+

1

1 2

(c)Average rate of reaction =

5060

// 1.2 cm3s-1

1 1

(d)(i) Rate of reaction Experiment C is higher than Experiment B 1 1

(ii) H2SO4 is diprotic acid //dissociate completely in water

to/ produce higher concentration of hydrogen ion, H+

The number of particles/H+ per unit volume is higher

The frequency of collision between hydrogen ion/H+ and Magnesium

atom is higher

The frequency of effective collision is higher

1

1

1

1 4

TOTAL 10

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5 (a) Chemical reaction involves oxidation and reduction occurring simultaneously 1 1

(b) To detect the current flow//produced 1 1

(c)(i) Oxidising agent : bromine water

Reducing agent : iron(II) ion// iron(II) sulphate

1

1 2

(ii) Electrode X : Fe2+ Fe3+ + e-

Electrode Y : Br2 + 2 e- 2 Br-

1

1 2

(d)

1 1

(e) Potassium iodide solution 1 1

(f) 0 -1 1 1

(g) Add sodium hydroxide, NaOH, solution/ ammonia solution, NH3(aq)

brown precipitate

1

1 2

TOTAL 11

electron flow

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6 (a) Heat change/release when one mole of a metal is displaced from its salt

solution by a more electropositive metal

1 1

(b) state any one of the observation

Brown solid is deposited/ formed/

Blue solution becomes colourless

Zinc metal dissolves

1 1

(c) Zn + Cu2+ → Zn2+ + Cu

(correct reactants and products – 1M)

(correct balance chemical equation – 1M)

1+1 2

(d)(i) H = mC

= (50)(4.2)(8)

= 1680 J// 1.68 kJ 1 1

(ii)

Mole of CuSO4 =1000

2.050x

= 0.01 mol 1 1

(iii)Heat of displacement of copper =

01.068.1

= 168 kJmol-1

ΔH= - 168 kJmol-1 1 1

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(e)

y-axis with label of energy

Two different energy levels + correct chemical/ionic equation

ΔH= - 168 kJmol-1

1

1

1 3

(f) Magnesium /Aluminium 1 1

TOTAL 11

EnergyZn + Cu2+

Cu + Zn2+

ΔH= - 168 kJmol-1

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SECTION B

No. Sample answer SubMarks

TotalMarks

7(a)(i) Continuous variation1 1

7(a)(ii) Height of precipitate (cm)Tinggi mendakan (cm)

P1 - axes and label(paksi dan label)

P2 – unit(unit)P3 - shape of the graph(bentuk graf)

Volume of barium chloride (cm3)Isipadu larutan barium klorida (cm3)

111

3

7(a)(iii) Volume of 0.5 mol dm-3 barium chloride solution needed to react completelywith 5.0 cm3, 0.5 mol dm-3 potassium chromate(VI) solution = 5 cm3

Isipadu larutan barium klorida 0.5 mol dm-3 yang diperlukan untuk bertindakbalas lengkap dengan 5 cm3 larutan kalium kromat(VI) 0.5 mol dm-3 = 5 cm3

Number of mole of barium chloride = M V(Bilangan mol barium klorida) 1000

= (0.5)(5)1000

= 0.0025 mol

P1 – Volume of BaCl2 (Isipadu BaCl2)P2 – Calculation/steps (Langkah pengiraan)P3 – Answer with unit (Jawapan dengan unit)

1

11 3

7(a)(vi) Ba2+ + CrO42- → BaCrO4

P1 – reactants (bahan)P2 – product (hasil)

1+1 2

7(b)(i) P1 - Nitrate ionP2 - Add 2 cm3 dilute sulphuric acid to 2 cm3 salt x solution in a test tube.

11

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P3 - Add 2 cm3 iron(II) sulphate solution to the solution and mix well.P4 - Add a few drops concentrated sulphuric acid from the side of slanted testtube.P5 – A brown ring is produced.

1

11 5

7(b)(ii) P1 + P2 – Lead(II) ion and Aluminium ion maybe present.P3 – Pour 2 cm3 potassium iodide solution to a test tube containing 2 cm3 saltx solution.P4 – Shake well.P5 – If yellow precipitate is formed,P6 – lead(II) ion is confirmed present.

1+1

1111 6

TOTAL 20

No. Sample answer SubMarks

TotalMarks

8(a)(i) Polymer is a long-chained molecules,which is consists of repeating units of monomers.

Polimer adalah molekul berantai panjang,yang terdiri daripada mengulangi unit monomer.

11

2

8(a)(ii) CH3

C

H

C

HH

1 1

8(a)iii) PropenePropena 1 1

8(a)(vi) To manufacture piping / bottle crates / carpets / car batteries / ropesUntuk pembuatan paip / peti botol / permaidani / bateri kereta / tali

Able to state any two uses of polymer

1+1 2

8(b)(i) Detergent dissolved in water and reduces the surface tension of waterDetergen larut dalam air dan mengurangkan ketegangan permukaanair

It ionises in water to form sodium ions, Na+ and detergent anionsIa mengion dalam air untuk membentuk ion natrium, Na+ dan aniondetergen

1

1

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Detergent anions consist of hydrophobic and hydrophilic partsAnion detergen terdiri daripada bahagian-bahagian hidrofobik danhidrofilik

Hydrophilic part dissolved in water and hydrophobic part dissolved ingrease.Bahagian hidrofilik larut dalam air dan sebahagian hidrofobik larutdalam gris.

The movement of water lifts the grease off the surfacePergerakan air mengangkat gris di luar permukaan

The grease is broken into smaller droplets that are suspended in waterforming an emulsionGris dibahagikan kepada titisan kecil yang terampai di dalam airmembentuk emulsi

The greasy droplets which carry the same charge repel one anotherTitisan gris yang membawa cas yang sama menolak antara satu samalain

When the cloth is rinsed with water, the greasy droplets will beremovedApabila kain itu dibilas dengan air, titisan gris akan dikeluarkan

1

1

1

1

1

18

8(b)(ii) Strength : Able to cleanse in hard water and acidic waterKelebihan : Dapat membersih dalam air liat dan berasid.

Weakness : Non-biodegredableKelemahan: Tidak terbiodegredasi

1

1 2

8(c)Tradisional medicineUbat tradisional

Modern medicineUbat moden

Example : Aloe VeraContoh: Aloe Vera

Example : AspirinContoh : Aspirin

Uses : To treat skin woundsKegunaan: Merawat lukakulit

Uses : To relive painKegunaan : Mengurangkankesakitan

1+1

1+1 4

TOTAL 20

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SECTION C

No. Sample answer SubMarks

TotalMarks

9(a)(i)1

12

9(a)(ii) Q – Propane /Propana

P – Propanol /Propanol

OR / ATAUQ – Etane /Etana

P – Ethanol /Etanol

11 2

9(a)(iii) Compound R:1. Burnt in excess oxygen to produce carbon dioxide and water.

Terbakar dalam oksigen berlebihan untuk menghasilkan karbondioksida dan air.

2. Can be oxidised to carboxylic asid.Boleh dioksidakan kepada asid karboksilik.

Compound S:Has a fragrant/fruity smell // insoluble in water // volatile // having dense than

water// soluble in organic solvents // a colourless liquid

Berbau harum/buah // tidak larut air // meruap // lebih tumpat dari air // larut

dalam pelarut organic // cecair tidak bewarna

State correctly any two of the above statement

1

1

1+1

4

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9(b) 3H8 + 502 3 CO2 + 4 H2O

Correct formula of reactants of reactants & products: 1M

Correct balanced chemical equation: 1M

1 mol of C3H8 produce 3 moles of CO21 mol C3H8menghasilkan 3 mol CO2

Therefore, the number of mol of CO2 producedMaka, bilangan mol CO2 terhasil= 0.05 X 3= 0.15 mol

The volume of CO2 producedIsi padu CO2 yang terhasil= 0.15 X 24.0= 3.6 dm3

ATAU / OR

C2H6 +2702 2CO2 + 3H2O /

2C2H6 + 702 4CO2 + 6H2O

1 mol of C2H6 produce 2 moles of CO21 mol C2H6menghasilkan 2 mol CO2

Therefore, the number of mol of CO2 producedMaka, bilangan mol CO2 terhasil

= 0.05 mol X 2= 0.1 mol

The volume of CO2 producedIsi padu CO2 yang terhasil= 0.1 X 24.0= 2.4 dm3

1+1

1

1

15

9(c) A few drops of acidified potassium manganate(VII) solution is added tocompound Q and R.Beberapa titis larutan kalium manganat(VII) berasid ditambahkan ke dalamsebatian Q dan R.

Compound Q does not show any changes.Sebatian Q tidak akan menunjukkan perubahan.

1

1

1

C

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Compound R decolourise the purple color of acidified potassiummanganate(VII) solution.Sebatian R akan menyahwarnakan warna ungu kalium manganat(VII)berasid.

OR /ATAU

A few drops of bromine water are added to compound Q and R.Beberapa titis air bromin ditambahkan ke dalam sebatian Q dan R.

Compound Q does not show any changes.Sebatian Q tidak akan menunjukkan perubahan.

Compound R decolourise the brown color of bromine water.Sebatian R akan menyahwarnakan warna perang air bromin.

3

9(d)(i) The number of double bonds reduces thus vulcanized rubber is not easilyspoiled by oxygen in air, ultraviolet rays or chemicals.Bilangan ikatan dubel/ganda dua berkurangan maka getah tervulkantidak mudah dirosakkan oleh oksigen dalam udara, sinaran ultraungu ataubahan kimia.

1 1

9(d)(ii) The sulphur cross-link will pull the chains back to their original arrangement.Rangkai silang sulfur akan menarik rantai polimer kembali kepada susunanasalnya.

1 1

9(d)(iii) When the molecular size increases, the Van der Waals attractive forcesbetween molecules increases.Apabila saiz molekul bertambah, daya tarikan Van der Waals antara molekulbertambah.

More energy needed to overcome the attractive force.Lebih banyak tenaga diperlukan bagi mengatasi daya tarikan tersebut.

1

1 2

TOTAL 20

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No. Sample answer SubMarks

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10(a) Any one type of strong acid :Hydrochloric acid // Nitric acid // Sulphuric acid,

Acid reacts with a base / alkali to produce salt and water //Hydrochloric acid reacts with sodium hydroxide / (any base/alkali) to producesodium chloride and water.

HCl + NaOH NaCl + H2O

Acid reacts with a reactive metal to produce salt and hydrogen //Hydrochloric acids react with Magnesium / Zinc to produce magnesiumchloride / zinc chloride and hydrogen.

Mg + 2HCl MgCl2 + H2

Acid reacts with a carbonate metal to produce salt, carbon dioxide and water// Hydrochloric acids reacts with calcium carbonate / (any metal carbonate) toproduce calcium chloride, carbon dioxide and water

CaCO3 + 2HCl CaCl2 + CO2 + H2O

1

1

1

1

1

1 6

10(b) Solution A:Ethanoic acid partially ionizes/dissociate in water to produce hydrogen ions,The presence of freely moving hydrogen/ions cause solution A / ethanoic acidto show its acidic properties.

Solution B:Without water / in propanone ethanoic acid still exists as molecule,No freely moving hydrogen/ions present, hence it does not shows its acidicproperties.

1

1

11 4

10(c) The material and apparatus neededThe calculation involveThe step involve in preparation

Materials :Solid sodium hydroxide and distilled water.

Apparatus :50 cm3 beaker, 250 cm3 volumetric flask, electronic balance, glass rod, filterfunnel.

1

1

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Determine the mass of sodium hydroxide, NaOH:

No. of moles of NaOH = 1 x 250 = 0.25 mol1000

Mass of NaOH needed = No. of moles x Molar mass of NaOH= 0.25 x 40= 10 g

1. Using an electronic balance, 10 g of sodium hydroxide is exactlyweighed and placed into a beaker.

2. Distilled water is added to the beaker to dissolve all the solid sodiumhydroxide.

3. Then the solution is poured into 250 cm3 volumetric flask.4. The beaker is rinsed with distilled water and the solution is poured

into the volumetric flask.

5. The solution in the volumetric flask is topped up with distilled wateruntil its calibration mark.

1

1

1+1

11

1

110

TOTAL 20