Pat kimia ting 4 paper 2 (2017) answer scheme by Intan

ANSWER SCHEME

PAT KIMIA P2 TING. 4 (2017)

a: accept ; r: reject ; adp: avoid double penalty ; wcr: wrong cancels right ; ecf: error carried forward ; bod: benefit of doubt Question Answer Marks 1 (a) (i) Substance which ionize / dissociates in water to form hydroxide ions / 1 OHBahan yang mengion / terurai dalam air menghasilkan ion hidroksida / OH(ii) S 1 (iii) Hydrochloric acid / HCl / Asid hidroklorik // 1 Nitric acid / HNO3 / Asid nitrik // Sulphuric acid / H2SO4 / Asid sulfurik (iv) From colourless to pink 1 Daripada tidak berwarna kepada merah jambu (b) (i) Vinegar / Cuka / T 1 a: ethanoic acid / asid etanoik (ii) Baking powder / serbuk penaik / U 1 a: sodium bicarbonate / natrium bikaronat / soda penaik (iii) 1. Mg(OH)2 1

Question 2 (a) (i)

(ii)

(b)

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(i)

2. Bacteria produces acid in the mouth Bakteria menghasilkan asid di dalam mulut

3. Magnesium hydroxide / Mg(OH)2 in toothpaste neutralizes the acid Magnesium hidroksida / Mg(OH)2 dalam ubat gigi meneutralkan asid itu TOTAL

Answer

Marks 1

Group 18, Period 2 Kumpulan 18, Kala 2 r: Group / Kumpulan 8 // Group / Kumpulan VIII // Group Eighteen / Kumpulan Lapan Belas // Second Period / Kala Kedua // Kala Ke2 1. Atom of element W has achieved stable octet electron arrangement Atom unsur W telah mencapai susunan elektron oktet yang stabil wcr: duplet / octet

2. Atom of element W does not donate / release, receive / accept / gain or share electrons with other atoms Atom unsur W tidak menderma / melepaskan, menerima atau berkongsi elektron dengan atom lain

Atom Y: 2.8.1

Atom Z: 2.8.8.1

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ANSWER SCHEME (ii)

PAT KIMIA P2 TING. 4 (2017)

1. Z

2. Size of atom Z is bigger / Saiz atom Z lebih besar // Atomic radius of Z is bigger / Jejari atom Z lebih besar // Number of shells of atom Z is more than atom Y / Bilangan petala atom Z lebih banyak berbanding atom Y a: Atom Z has 4 shells filled with electrons, atom Y has 3 shells filled with electrons / Atom Z mempunyai 4 petala berisi elektron, atom Y mempunyai 3 petala berisi elektron

3. Force of attraction between the nucleus and valence electron is weaker in atom Z / Daya tarikan antara nukleus dengan elektron valens lebih lemah dalam atom Z a: It is easier from atom Z to donate / release electrons Lebih mudah untuk atom Z menderma / melepaskan elektron

Note: atom must be mentioned in P2 / P3 (iii) In paraffin oil // dalam minyak parafin TOTAL

Question (a) (i)

Answer Covalent (bond) / (ikatan) kovalen r: incorrect spelling (ii) Carbon dioxide / karbon dioksida r: incorrect spelling (iii) 1. Low melting and boiling points Takat lebur dan takat didih yang rendah

(b)

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(i)

1 9

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2. Weak van der Waals / intermolecular force between molecules Daya van der Waals / antara molekul yang lemah

3. Small amount of heat is needed to overcome the forces Sedikit tenaga haba diperlukan untuk mengatasi daya itu // Small amount of heat is needed to break the bond. Sedikit tenaga haba diperlukan untuk memutuskan / memecahkan ikatan itu.

Correct drawing of Na+ Correct drawing of ClSample answer

+ Na

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(ii)

PAT KIMIA P2 TING. 4 (2017)

1. Sodium / Na atom donates / releases 1 electrons (to form sodium ion / Na+) Atom natrium / Na menderma / melepaskan 1 elektron (membentuk ion natrium / Na+)

2. Chlorine atom receives / accepts 1 electron, (to form chloride ion / Cl-) Atom klorin menerima satu elektron (membentuk ion klorida / Cl-)

3. Sodium ion / Na+ and chloride ion / Cl- are attracted by strong electrostatic force Ion natrium / Na+ dan ion klorida / Cl- ditarik oleh daya elektrostatik yang kuat

Note: Atom must be mentioned in P1 or P2 TOTAL

Question 4 (a)

(b)

Element/ Unsur C Mass / Jisim (g) 92.3 Number of moles / 92.3 / 7.69 Bilangan mol (mol) 12 Mole ratio / 7.69 / 1 Nisbah mol 7.69 Empirical formula = CH (CH)n = 78 // n [12 + 1] = 78 // 13n = 78 n=6

H 7.7 7.7 / 7.7 1 7.7 / 1 7.69

1 1 1 1

Molecular formula = (CH)6 = C6H6 (i) X: 4 Y: 3 (ii) 2 (mol) (iii) (2×56) + (3×16) + (2×1) + 16 // 178 r: answer with unit

1 1 1 1 1 TOTAL

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Marks 1

(i)

(ii)

(c)

Answer Formula that shows the simplest ratio of atoms of each element in a compound Formula yang menunjukkan nisbah teringkas atom setiap unsur dalam satu sebatian

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Question 5 (a) (i) (ii)

PAT KIMIA P2 TING. 4 (2017)

Answer

Haber Ammonium sulphate / Ammonium sulfat r: formula, incorrect spelling (eg: ammonia sulphate / ammonia sulfat) (iii) Correct formula of reactants and products Correct balancing of equation 2NH3 + H2SO4  (NH4)2SO4 (iv) 1. % N of (NH4)2SO4 = 2×14 × 100 // 2 [14 + (4×1)] + 32 + (4×16) = 28 × 100 // 132 = 21.2% / 21.21% / 21% 2. % N of CO(NH2)2 = 2×14 12 + 16 + {2 [14 + (2×1)]} = 28 × 100 // 60 = 46.7% / 46.67% / 47%

(b)

1 1

1 × 100 //

3. Urea / CO(NH2)2 is a better fertilizer Urea / CO(NH2)2 ialah baja yang lebih baik

(i)

Large / long chain molecule that is made up of many identical repeating sub-units / monomer // Molekul besar / berantai panjang yang dibina oleh ulangan banyak unit asas / kecil / monomer

(ii)

Propene / Propena

(iii) 1. Advantage / Kelebihan: i. easy to mould / mudah dibentuk // ii. cheap / murah // iii. easy to colour / mudah diwarnakan // iv. very stable / sangat stabil // v. does not corrode / tidak terkakis vi. lighter / lebih ringan 2. Disadvantage / Kekurangan: i. Not biodegradable / tidak terbiodegradasi a: Difficult to dispose / sukar dilupuskan

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PAT KIMIA P2 TING. 4 (2017)

ii. can cause pollution / boleh menyebabkan pencemaran TOTAL Question 6 (a) (i)

(b)

(c)

Answer

ALL ions must be mentioned Copper(II) ion / Cu2+ / ion kuprum(II), r: Copper ion / ion kuprum Sulphate ion / SO42- / ion sulfat, Hydrogen ion / H+ / ion hidrogen, r: Hydrogen / hidrogen (the word ‘ion’is not mentioned) Hydroxide ion / OH- / ion hidroksida (ii) Becomes thinner / menjadi nipis / menipis r: corrodes / erodes / terkakis / terhakis (iii) Cu  Cu2+ + 2e (iv) Brown solid deposited / Pepejal perang terenap // Electrode becomes thicker / Elektrod menjadi tebal/menebal (v) Cu2+ + 2e  Cu (i) Anode / Anod : Oxygen (gas) / O2 / (Gas) oksigen Cathode / Katod : Aluminium / Al (ii) Substance / Bahan P : Cryolite / Na3AlF6 / Kriolit

11 Marks 1

1 1 1 1 1 1 1

Function: Lower the melting point of aluminium oxide / Al 2O3 Merendahkan takat lebur aluminium oksida / Al2O3 Functional diagram : 1. impure silver at anode / argentum tak tulen di anod 2. pure silver at cathode/ argentum tulen di katod 3. dashes ‘-‘ drawn to represent solution

Label : 1. impure silver / argentum tak tulen 2. pure silver / argentum tulen 3. silver nitrate solution / larutan argentum nitrat a: AgNO3 solution / larutan AgNO3

Sample answer:

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PAT KIMIA P2 TING. 4 (2017) TOTAL

Question (a)

Answer 1. Sodium hydroxide / NaOH is an ionic compound Natrium hidroksida / NaOH ialah sebatian ion r: sebatian ionic

11 Marks 1

2. Sodium hydroxide/ NaOH (dissolves in water), does not dissolve in organic solvent Natrium hidroksida / NaOH (larut dalam air), tidak larut dalam pelarut organic

3. Hexane is an organic solvent Heksana ialah pelarut organic

4. Naphthalene is a covalent compound Naftalena ialah sebatian kovalen

5. Naphthalene dissolves in organic solvent Naftalena larut dalam pelarut organic

1 Max.

(b)

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Ionic compound Sebatian ion 1. High melting and boiling points Takat lebur dan takat didih tinggi

Covalent compound Sebatian kovalen Low melting and boiling points Takat lebur dan takat didih rendah

2. Ions are attracted by strong electrostatic force Ion-ion ditarik oleh daya elektrostatik yang kuat

Molecules are held together by weak intermolecular / van der Waals forces Molekul-molekul ditarik oleh daya antara molekul / van der Waals yang lemah

3. A lot of heat is required to overcome the forces / break the bond Banyak haba diperlukan untuk mengatasi daya / memutuskan ikatan itu

Little heat is required to overcome the forces / break the bond Sedikit haba diperlukan untuk mengatasi daya / memutuskan ikatan itu

4. Conduct electricity in molten and aqueous state

Does not conduct electricity in any state

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PAT KIMIA P2 TING. 4 (2017)

Boleh mengkonduksikan elektrik dalam keadaan leburan atau akueus // 5. There are free moving ions (to carry electrical charges) Terdapat ion-ion yang bebas bergerak (untuk membawa cas elektrik)

Tidak megkonduksikan elektrik dalam mana-mana keadaan

6. Cannot conduct electricity in solid state Tidak mengkonduksikan elektrik dalam keadaan pepejal

Does not conduct electricity in any state Tidak megkonduksikan elektrik dalam mana-mana keadaan

7. Ions are fixed in crystal lattice structure Ion-ion tetap dalam struktur kekisi hablur

No free moving ions Tiada ion yang bergerak bebas // Consists of neutral molecules Terdiri daripada molekul neutral

1 8. Dissolves in water Larut dalam air

Does not dissolve in water Tidak larut dalam air 1

9. Does not dissolve in organic solvent Tidak larut dalam pelarut organik (c)

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Dissolves in organic solvent Larut dalam pelarut organik

Max. 1. The electron arrangement of atom P is 2.8.2 // Susunan elektron atom P ialah 2.8.2

6 1

2. To achieve stable octet electron arrangement // Untuk mencapai susunan elektron oktet yang stabil

3. Atom P donates / release 2 valence electrons // Atom P menderma / melepaskan 2 elektron valens

4. forming ion P / P2+ // membentuk ion P / P2+ // P ď&#x192; P2+ + 2e

5. The electron arrangement of atom Q is 2.6 // Susunan elektron atom Q ialah 2.6

6. Atom Q receives / accepts / gains 2 electrons // Atom Q menerima 2 elektron

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PAT KIMIA P2 TING. 4 (2017)

7. forming ion Q / Q2- // membentuk ion Q / Q2 // Q + 2e ď&#x192; Q28. ion P / P2+ and ion Q / Q2- are attracted by electrostatic force // ion P / P2+ dan ion Q / Q2- ditarik oleh daya elektrostatik

9. Ionic compound, (PQ) is formed // Sebatian ion, (PQ) terbentuk

10. Correct diagram of P ion

11. Correct diagram of Q ion

2+ P

Note: atom must be mentioned in P1 / P3 and P5 / P6 Max. TOTAL

Question (a)

Answer P 1. Borosilicate / Fused glass Kaca borosilikat / silika terlakur 2. Heat resistant / Tahan terhadap haba // High resistance towards thermal shock / Rintangan yang tinggi terhadap kejutan terma / haba // Durable towards chemicals / Tahan terhadap bahan kimia // Low thermal expansion coefficient / Mempunyai pekali pengembangan terma / haba yang tinggi // Transaperent / Lut sinar // Great purity / Mempunyai ketulenan yang tinggi Q 3. Fibre optic Gentian optic 4. High transmission capacity / Dapat menghantar data dalam kapasiti yang tinggi dan cepat // Less susceptible towards interference / Kurang gangguan interferens //

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PAT KIMIA P2 TING. 4 (2017)

Chemically stable / Stabil secara kimia

(b)

(c)

1. Molten sulphur is burnt in dry air to produce sulphur dioxide Sulfur lebur dipanaskan dalam udara kering untuk menghasilkan sulfur dioksida

2. S + O2  SO2

3. Sulphur dioxide / SO2 and excess oxygen / O2 are passed over vanadium(V) oxide / V2O5 Sulfur dioksida / SO2 dan oksigen / O2 berlebihan disalurkan kepada vanadium(V) oksida / V2O5

4. Temperature / Suhu: 450°C a: 450 – 550°C

5. Sulphur trioxide / SO3 is formed Sulfur trioksida / SO3 terbentuk

6. 2SO2 + O2

2SO3

7. Sulphur trioxide / SO3 is reacted with concentrated sulphuric acid / H2SO4 Sulfur trioksida / SO3 ditindakbalaskan dengan asid sulfurik pekat / H2SO4

8. Oleum / H2S2O7 is formed Oleum / H2S2O7 terbentuk

9. SO3 + H2SO4  H2S2O7

10. Oleum / H2S2O7 is diluted with water Oleum / H2S2O7 dicairkan dengan air

11. Concentrated sulphuric acid / H2SO4 is formed Asid sulfurik / H2SO4 pekat terhasil

12. H2S2O7 + H2O  2H2SO4

1 10 1

Max. 1. Sulphur dioxide / SO2 causes respiratory problems in humans Sulfur dioksida / SO2 menyebabkan masalah pernafasan kepada manusia 2. Sulphur dioxide / SO2 reacts with water and oxygen to form acid rain

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Sulfur dioksida / SO2 bertindak balas dengan oksigen untuk membentuk hujan asid 3. Acid rain flows into lakes and rivers Hujan asid mengalir ke dalam tasik dan sungai

4. Lakes and rivers become acidic Tasik dan sungai menjadi berasid // pH of lakes and rivers decrease pH tasik dan sungai berkurang

5. Fish and other aquatic organisms die Ikan dan hidupan akuatik mati

6. Acid rain causes pH of soil to decrease Hujan asid menyebabkan pH tanah berkurang // Acid rain causes soil to be acidic Hujan asid menyebabkan tanah menjadi berasid

7. Salts are leached out of the top soil Garam mineral larut resap di dalam tanah

8. Roots of trees are destroyed Akar pokok rosak

9. Plants die of malnutrition and diseases Tumbuhan mati akibat malnutrisi dan penyakit

1 Max. TOTAL

Question (a) (i)

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Answer HCl in water HCl dalam air 1. HCl ionizes / dissociates in water HCl mengion / bercerai dalam air

HCl in tetrachloromethane HCl dalam tetraklorometana HCl does not ionize / dissociate in water HCl tidak mengion / bercerai dalam air

2. Hydrogen / H2 gas is produced Gas hidrogen / H2 dihasilkan // Reaction occurs Tindak balas berlaku

Hydrogen / H2 gas is not produced Gas hidrogen / H2 tidak dihasilkan // Reaction does not occur Tindak balas tidak berlaku

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PAT KIMIA P2 TING. 4 (2017)

3. Hydrogen ion / H+ present Ion hidrogen / H+ hadir

No hydrogen ion / H+ Tiada ion hidrogen / H+ // HCl remains as molecule HCl kekal sebagai molekul

4. Acidic property is shown Sifat asid ditunjukkan

Acidic property is not shown Sifat asid ditunjukkan Total

(ii)

Correct formula of reactants and products Correct balancing of equation Mg + 2HCl  MgCl2 + H2

1 4 1 1

(b) Cause Sebab 1. Acidic soil Tanah berasid

Ways to overcome Cara mengatasi 2. Add calcium oxide / soda lime / calcium carbonate / limestone / wood ash Tambah kalsium oksida / kapur tohor / abu kayu

3. Alkaline / basic soil Tanah beralkali / berbes

4. Add sulphur / iron(II) sulphate / compost Tambah sulfur / ferum(II) sulfat / kompos

5. Lack of nutrient / fertilizer / nitrogen Kurang nutrien / baja / nitrogen

6. Add urea / ammonium nitrate / ammonium sulphate / ammonium phosphate Tambah urea / ammonium nitrat / ammonium sulfat / ammonium fosfat r: acid / organic fertilizer / ammonia nitrate / ammonia sulphate / ammonia phosphate Max.

(c)

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1. Volumetric flask used is 250 cm Kelalang volumetrik yang digunakan ialah 250 cm3

1+1

4 1

2. Mass of potassium hydroxide needed Jisim kalium hidroksida yang diperlukan = 0.25 mol × 56 g mol-1 // 14 g

3. Weigh 14 g of KOH in a beaker Timbang 14 g KOH dalam bikar

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Question 10 (a)

PAT KIMIA P2 TING. 4 (2017)

4. Add water Tambah air

5. Stir until all KOH dissolve Kacau sehingga semua KOH larut

6. Pour the solution into volumetric flask Tuang larutan ke dalam kelalang volumetrik

7. Rinse beaker, glass rod and filter funnel Bilas bikar, rod kaca dan corong turas

8. Add water Tambah air

9. When near graduation / calibration mark, add water drop by drop until meniscus reaches graduation / calibration mark Apabila hampir dengan tanda senggatan, tambah air setitis demi setitis sehingga miniskus mencecah tanda senggatan

10. Stopper the volumetric flask and shake the solution Tutup kelalang volumetrik dengan penutup dan goncang larutan Total TOTAL

Answer Test for Zn2+ Using sodium hydroxide / NaOH solution 1. Add a few drops of sodium hydroxide / NaOH solution until in excess into salt solution X Tambah beberapa titis larutan natrium hidroksida / NaOH sehingga berlebihan ke dalam larutan garam X

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1 2. White precipitate dissolved (in excess sodium hydroxide / NaOH solution) to produce a colourless solution Mendakan putih larut dalam larutan natrium hidroksida / NaOH berlebihan menghasilkan larutan tak berwarna Using ammonia / NH3 solution 3. Add a few drops of ammonia / NH3 solution until in excess into salt solution X Tambah beberapa titis larutan ammonia / NH3 sehingga berlebihan ke dalam larutan garam X

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4. White precipitate dissolved in excess ammonia / NH3 solution to produce a colourless solution Mendakan putih larut dalam larutan ammonia / NH3 berlebihan menghasilkan larutan tak berwarna Test for SO425. Add [2 – 5 cm3] hydrochloric acid / HCl into salt solution of X, followed by [2 – 5 cm3] of barium chloride solution Tambah [2 – 5 cm3] asid hidroklorik / HCl ke dalam larutan garam X, diikuti oleh [2 – 5 cm3] larutan barium klorida 6. White precipitate forms Mendakan putih terbentuk

1 Total

(b) Example of salt Contoh garam 1. Sodium chloride / NaCl / natrium klorida

Usage in daily life Kegunaan dalam kehidupan seharian 2. Table salt / garam makan // preservative / pengawet // flavouring / perisa

Ammonium nitrate / NH4NO3 / ammonium nitrat // ammonium sulphate / (NH4)2SO4 / ammonium sulfat // ammonium phosphate / (NH4)3PO4 / ammonium fosfat // potassium chloride / KCl / kalium klorida

4. Fertilizer / Baja

Copper(II) sulphate / CuSO4 / kuprum(II) sulfat // iron(II) sulphate / FeSO4 / ferum(II) sulfat

6. Pesticides / racun serangga

1+1

Silver bromide / AgBr / argentum bromida

8. Making photographic paper / membuat kertas fotografi

1+1

[any other suitable answers] Max. (c)

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1. Pour [50 – 250 cm3] of [0.1 – 2.0 mol dm-3] sulphuric acid into a beaker Tuang [50 – 250 cm3] asid sulfurik [0.1 – 2.0 mol dm-3] ke dalam sebuah bikar © 2017 Hak Cipta Panitia Kimia SMK Sultan Yussuf

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2. Warm the acid Hangatkan asid itu

3. Add zinc / Zn / zinc oxide / ZnO / zinc carbonate / ZnCO3 powder little by little into the acid Tambah serbuk zink / Zn / zink oksida / ZnO / zink karbonat / ZnCO3 sedikit demi sedikit ke dalam asid itu

4. Stir the mixture Kacau campuran itu

5. Add zinc / Zn / zinc oxide / ZnO / zinc carbonate / ZnCO3 powder continuously until in excess / some of it no longer dissolve Tambah serbuk zink / Zn / zink oksida / ZnO / zink karbonat / ZnCO3 berterusan sehingga berlebihan / tidak larut lagi

6. Filter the mixture to remove excess / unreacted zinc / Zn / zinc oxide / ZnO / zinc carbonate / ZnCO3 Turas campuran itu untuk mengasingkan zink / Zn / zink oksida / ZnO / zink karbonat / ZnCO3 berlebihan / yang tidak bertindak balas

7. Transfer / pour the filtrate into an evaporating dish Pindahkan / tuang hasil turasan ke dalam mangkuk penyejat

8. Heat gently to produce a saturated solution // one-third / onequarter of the original volume Panaskan perlahan-lahan untuk menghasilkan larutan tepu // satu pertiga / satu perempat daripada isi padu asal

9. Cool (to room temperature) Sejukkan (pada suhu bilik)

10. Filter the crystals Turaskan hablur

11. Dry the crystals between filter papers Keringkan hablur antara kertas turas

12. Zn + H2SO4  ZnSO4 + H2 // ZnO + H2SO4  ZnSO4 + H2O // ZnCO3 + H2SO4  ZnSO4 + H2O + CO2

Max. TOTAL

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