Ppt kimia ting 4 paper 2 (2018) answer scheme by izzahedi

ANSWER SCHEME

PPT KIMIA P2 TING. 4 (2018)

a: accept ; r: reject ; adp: avoid double penalty ; wcr: wrong cancels right ; ecf: error carried forward ; bod: benefit of doubt 1

Question

Answer

Marks

(a)

Atoms of the same element with the same proton number but different nucleon number Atom-atom unsur yang sama yang mempunyai nombor proton yang sama tetapi nombor nukleon yang berbeza // Atoms of the same element with the same number of protons but different number of neutrons Atom-atom unsur yang sama yang mempunyai bilangan proton yang sama tetapi bilangan neutron yang berbeza

(b)

(c)

(i)

Particle Zarah Number of electron Bilangan elektron

Number of neutron Bilangan neutron

(ii)

Carbon dating Pentarikhan karbon // Estimate the age of fossils and artefacts Menganggar usia fosil dan artifak r : fossil fuels

(i)

1. Correct axes and unit + correct shape of graph 2. Correct label of melting point

1 1

Sample answer:

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ANSWER SCHEME

PPT KIMIA P2 TING. 4 (2018)

Accept:

Reject [graph drawn from origin but it is not labelled as 30Â°C]

(ii)

1. 51

1. Heat loss / released to the surroundings Haba yang hilang / dibebaskan ke sekeliling / persekitaran 2. Equally balanced with heat liberated / released as particles attract one another Diimbangi oleh haba yang yang terbebas apabila zarah-zarah menarik antara satu sama lain

TOTAL

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ANSWER SCHEME Question 2

PPT KIMIA P2 TING. 4 (2018) Answer

Marks

(a)

(Period) / (Kala) 3 r : three / tiga

(b)

Chlorine / Klorin / Cl a : Cl2

(c)

Aluminium / Al r : aluminium oxide / aluminium oksida / Al2O3

(d)

Silicon / Silikon / Si

(e)

1. Atomic size / radius decreases Saiz / jejari atom berkurang 2. Attraction force between nucleus and its valence electrons becomes stronger Daya tarikan antara nukleus dengan elektron valens menjadi lebih kuat // Nuclei charge increases Cas nuklei bertambah // Atom easier to receive / accept electrons Atom lebih mudah menerima elektron

(i)

1. Correct formulae of reactants and product 2. Balanced equation Answer: 4Na + O2 â&#x2020;&#x2019; 2Na2O

1 1

(ii)

Red coloured litmus paper change to blue Warna kertas litmus merah bertukar menjadi biru

(f)

TOTAL

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ANSWER SCHEME Question 3

(a)

(b)

PPT KIMIA P2 TING. 4 (2018) Answer

Marks

(i)

The (chemical) formula that shows the actual number of atoms of each element in a molecule / compound // Formula (kimia) yang menunjukkan bilangan atom yang sebenar bagi setiap unsur dalam satu molekul / sebatian

(ii)

CH2O

(iii) 1. Reactants : Carbon dioxide / CO2 and water / H2O Bahan tindak balas : Karbon dioksida / CO2 dan air / H2O 2. Products : Glucose / C6H12O6 and oxygen / O2 Hasil tindak balas : Glukosa / C6H12O6 dan oksigen / O2 3. Mole ratio : 6 mol CO2 reacts with 6 mol H2O produces 1 mol C6H12O6 and 6 mol O2 / Nisbah mol : 6 mol CO2 bertindak balas dengan 6 mol H2O menghasilkan 1 mol C6H12O6 dan 6 mol O2 Note 1. If mol is replaced with molecule, can award P3, provided, all are replaced 2. If extra info contradicts the equation, apply wcr once only Eg: P1 P2 P3 P4 P5

(i)

X:4 Y:3 Z:2

1 1 1

(ii)

2 (mol) Note 1. ecf from 3(b)(i)

(iii) 178 r: 178 g mol-1 (RFM cannot have any unit)

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1 TOTAL

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ANSWER SCHEME Question 4

(a)

(b)

(c)

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PPT KIMIA P2 TING. 4 (2018) Answer

Marks

(i)

1 / alkali metal / logam alkali r : one / satu

(ii)

Valence electron is one // elektron valens ialah satu a : same number of valence electron // bilangan elektron valens yang sama a : same valence electron // elektron valens yang sama a : outermost shell filled with one electron // petala terluar diisi dengan satu elektron

(iii) 2.8.1

(i)

1. Atom R has bigger radius / atomic size Jejari / saiz atom R lebih besar // Atom R has more number of shells occupied with electrons Atom R mempunyai bilangan petala berisi elektron yang lebih banyak 2. Force of attraction between nucleus and valence electron in atom R is weaker Daya tarikan antara nukleus dengan elektron valens dalam atom R lebih lemah // Nuclei attraction of atom R is weaker Tarikan nuklei atom R lebih lemah // Electrostatic force between nucleus and valence electron in atom R is weaker Tarikan elektrostatik antara nukleus dengan elektron valens dalam atom R lebih lemah 3. Atom R easier to donate electron Atom R lebih mudah menderma elektron Note: P1 & P3 must have the word ‘atom’

1. Correct formulae of reactants and products 2. Balanced equation Answer: 4T + O2 → 2T2O // 4Li + O2 → 2Li2O a : 2T + ½ O2 → T2O

1 1

(i)

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ANSWER SCHEME (ii)

PPT KIMIA P2 TING. 4 (2018)

1. Ratio of moles 0.1 mol T : 0.05 mol T2O // 2 mol T : 1 mol T2O // 4 mol T : 2 mol T2O 2. Mass of product with unit Mass T2O = 0.05 × 30 g // 1.5 g Note: ecf mole ratio from 3(c)(i) for P1 (because only 1 product & the reactant has already been specified in the question) TOTAL

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ANSWER SCHEME Question 5

PPT KIMIA P2 TING. 4 (2018) Answer

Marks

(a)

to dry hydrogen gas // untuk mengeringkan gas hidrogen // to absorb water vapour // untuk menyerap wap air

(b)

1. Mass of copper and oxygen Mass of copper = (26.52 – 24.60) / 1.92 Mass of oxygen = (27.00 – 26.52) / 0.48 2. Number of moles of copper and oxygen Number of moles of copper = 1.92 / 0.03 64 Number of moles of oxygen = 0.48 / 0.03 16 3. Empirical formula : CuO

Heating, cooling and weighing are repeated until a constant mass is obtained // Pemanasan, penyejukan dan penimbangan diulang sehingga jisim tetap diperoleh

(i)

Cannot / Tidak boleh / No / Tidak

(ii)

Magnesium is more reactive than hydrogen // Magnesium lebih reaktif berbanding hidrogen a: Magnesium is more reactive // Magnesium lebih reaktif r: Magnesium is more electropositive // Magnesium lebih elektropositif

(i)

X : Liquid / cecair Y : Solid / pepejal

1 1

(ii)

Any two answers 1. Melting point of substance Y is higher than substance X Takat lebur bahan Y lebih tinggi berbanding bahan X 2. Attraction force between particles / ion in Y is stronger Daya tarikan antara zarah-zarah / ion dalam Y lebih kuat // Attraction forces between molecules in X is weaker than in Y Daya tarikan antara molekul dalam X lebih lemah berbanding Y 3. More heat is required to overcome the attraction forces Lebih banyak haba diperlukan untuk mengatasi daya tarikan ini

(c)

(d)

(e)

1 1

1 Max. = 2

TOTAL

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ANSWER SCHEME Question 6

(a)

(b)

(c)

PPT KIMIA P2 TING. 4 (2018) Answer

Marks

(i)

Covalent (bond) / (ikatan) kovalen r : covalent compound / sebatian kovalen r : wrong spelling

(ii)

CO2

(i)

1. Correct formulae of reactant and products 2. Balanced equation Answer: CO2 + 2NH3 → H2O + CO(NH2)2

1 1

(ii)

1. Number of moles of CO2 = 36 = 1.5 mol 24 2. Mass of urea = 1.5 × 60 g // 90 g

(i)

(ii)

1. (C2H4O)n = 88 // n [(2 × 12) + (4 × 1) + 16] = 88 // 44n = 88 // n=2 2. C4H8O2

(iii) 1. Correct formulae of reactant and products 2. Balanced equation Answer: 2Cu(NO3)2 → 2CuO + O2 + 4NO2

1 1

TOTAL

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ANSWER SCHEME

Question 7

PPT KIMIA P2 TING. 4 (2018) Answer

(a)

Marks

Any four answers 1. Nucleus contains one proton and one neutron Nukleus mengandungi satu proton dan satu neutron 2. Electron moves in the orbit // around the nucleus Elektron bergerak di dalam orbit // mengelilingi nukleus 3. Electron is negatively charged Elektron bercas negatif 4. The atom has one shell Atom itu mengandungi satu petala 5. The atom is neutral Atom itu neutral 6. The atom has one (valence) electron Atom itu mempunyai satu elektron (valens)

1 1 1 1 1 1 Max. = 4

(b)

(i)

Any four answers Atom in Diagram 4.1

Another atom

Number of proton Bilangan proton

Number of neutrons Bilangan neutron

Number of electrons Bilangan elektron

Chemical properties Sifat kimia

Same / Similar Sama

Nucleon number Nombor nukleon

6. 7.

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Atomic mass Jisim atom

Lower Lebih rendah

Higher Lebih tinggi

Density Ketumpatan

Lower Lebih rendah

Higher Lebih tinggi

1 Max. = 4

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ANSWER SCHEME (ii)

(c)

PPT KIMIA P2 TING. 4 (2018)

1. Correct value of A 2. Correct value of Z Answer:

1 1

1. 18 2. Argon atom has achieved stable octet electron arrangement Atom argon telah mencapai susunan elektron oktet yang stabil 3. Argon atom does not donate, accept or share its electrons with other atoms Atom argon tidak menderma, menerima atau berkongsi elektron dengan atom lain 4. Argon is not reactive Argon tidak reaktif

1 1 1

1 Total = 4

(d)

1. The electron arrangement of X atom is 2.7 and Y atom is 2.8.7 Susunan elektron atom X ialah 2.7 dan atom Y ialah 2.8.7 2. The number of shells occupied with electrons of atom Y is more than atom X Bilangan petala berisi elektron atom Y lebih banyak berbanding atom X 3. The size of atom Y is bigger / larger than atom X Saiz atom Y lebih besar berbanding atom X 4. The outermost shell is further away from the nucleus in atom Y Petala paling luar lebih jauh daripada nukleus dalam atom Y 5. The force of attraction of the nucleus to attract one electron into the outermost shell of atom Y is weaker than in atom X Daya tarikan nukleus untuk menarik satu elektron ke dalam petala terluar atom Y lebih lemah berbanding atom X 6. The reactivity of element Y is lower than element X Kereaktifan unsur Y lebih rendah berbanding unsur X TOTAL

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1 1

1 1 1

1 Total = 6 20

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ANSWER SCHEME Question 8

(a)

PPT KIMIA P2 TING. 4 (2018)

Answer 1. % of N in (NH2)2CO / Fertilizer A = 2 × 14 × 100% // 28 × 100% // 46.67% { 2 [14 + (2 × 1)] } + 12 + 16 60 2. % of N in NH4NO3 / Fertilizer B = 2 × 14 × 100% // 28 × 100% // 35% [14 + (4 × 1) + 14 + (3 × 16)] 80

(b)

1. Correct formulae of reactant and products 2. Balanced equation Answer: 2Na + Cl2 → 2NaCl

1 1

4. Ratio of moles 2 mol Na : 1 mol Cl2 0.02 mol Na : 0.01 mol Cl2 5. Volume of Cl2 = 0.01 mol × 24 dm3 mol-1 // 0.24 dm3 1. 2. 3. 4. 5. 6. 7.

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3. Ammonium nitrate / NH4NO3 is a better fertilizer // Ammonium nitrat / NH4NO3 ialah baja yang lebih baik

3. Number of moles of Na = 0.46 g // 0.02 mol -1 23 g mol

(c)

Marks

The electron arrangement of hydrogen / H atom is 1 Susunan elektron atom hidrogen / H ialah 1 The hydrogen / H atom needs one electron Atom hidrogen / H memerlukan satu elektron To achieve a stable duplet electron arrangement Untuk mencapai susunan elektron duplet yang stabil The electron arrangement of oxygen / O atom is 2.6 Susunan elektron atom oksigen / O ialah 2.6 The oxygen / O atom needs two electrons Atom oksigen / O memerlukan dua elektron To achieve a stable octet electron arrangement Untuk mencapai susunan elektron oktet yang stabil One oxygen / O atom shares two pairs of electrons with two hydrogen / H atoms

1 Total = 5 1 1 1 1 1 1 1

SULIT

ANSWER SCHEME

PPT KIMIA P2 TING. 4 (2018)

Satu atom oksigen / O berkongsi dua pasang elektron dengan dua atom hidrogen / H 8. To form water molecule, with a formula of H2O Untuk membentuk molekul air, dengan formula H2O 9. One oxygen / O atom contributes two electrons and each of the hydrogen / H atom contributes one electron for sharing Satu atom oksigen / O menyumbang dua elektron dan setiap satu atom hidrogen / H menyumbang satu elektron untuk perkongsian 10. One oxygen / O atom forms two single covalent bonds with two hydrogen / H atoms Satu atom oksigen / O membentuk dua ikatan kovalen tunggal dengan dua atom hidrogen / H 11. Correct number of shells and nucleus drawn for every atom 12. Correct number of electrons drawn for every atom

1 1

Total = 12 TOTAL

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ANSWER SCHEME Question 9

(a)

13 Answer

1. Z, X, Y 2. X : Aluminium oxide / Aluminium oksida 3. Y : Sodium oxide / Natrium oksida // Magnesium oxide / Magnesium oksida 4. Z : Phosphorus pentoxide / Fosforus pentoksida // Sulphur dioxide / Sulfur dioksida // Chlorine oxide / Klorin oksida / Dichlorine heptoxide / Diklorin heptoksida 5. Correct formulae of reactant and products 6. Balanced equation Answers: Na2O + 2HCl → NaCl + H2O // MgO + 2HCl → MgCl2 + H2O // Y2O + 2HCl → 2YCl + H2O // YO + 2HCl → YCl2 + H2O Note: ecf P5 & P6 if answer in P3 is Al2O3

(b)

1. Correct formulae of reactant and products 2. Balanced equation Answer: 4K + O2 → 2K2O 3. Ratio of moles 4 mol K : 2 mol K2O 0.1 mol K : 0.05 mol K2O 4. Mass of K2O = 0.05 mol × 94 g mol-1 // 4.7 g

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PPT KIMIA P2 TING. 4 (2018)

Marks 1 1 1 1

1 1

Total = 6 1 1

1 Total = 4

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ANSWER SCHEME (c)

PPT KIMIA P2 TING. 4 (2018)

1. Named ionic compound : sodium chloride / natrium klorida // copper(II) sulphate / kuprum(II) sulfat // [any suitable ionic compound] 2. Named covalent compound : naphthalene / naftalena // sugar / gula / glukosa // [any suitable covalent compound] 3. Apparatus : crucible / mangkuk pijar, spatula / spatula, pipe clay triangle / segi tiga tanah liat, tripod stand / tungku kaki tiga, Bunsen burner / penunu Bunsen, carbon electrodes / elektrod karbon, ammeter, battery / bateri, connecting wires / wayar penyambung 4. Put one spatula of [sodium chloride] into a crucible Letakkan satu spatula [natrium klorida] ke dalam mangkuk pijar 5. Heat the [sodium chloride] Panaskan [natrium klorida] 6. Put the carbon electrodes into the [sodium chloride] Masukkan elektrod karbon ke dalam [natrium klorida] 7. Connect the carbon electrodes, ammeter and battery together, using connecting wires // Complete the circuit 8. Observe the deflection of ammeter needle Perhatikan pesongan jarum ammeter 9. Repeat the experiment using [naphthalene] to replace [sodium chloride] Ulang eksperimen menggunakan [naftalena] untuk menggantikan [natrium klorida] 10. [Sodium chloride] conducts electricity in molten state [Natrium klorida] mengkonduksikan elektrik dalam keadaan leburan 11. [Sodium chloride] contains free moving ions [Natrium klorida] mempunyai ion-ion yang bergerak bebas 12. Naphthalene does not conduct electricity in molten state [Naftalena] tidak mengkonduksikan elektrik dalam keadaan leburan 13. Naphthalene does not contain free moving ions [Naftalena] tiada ion-ion yang bergerak bebas // Naphthalene consists of free molecules Naftalena terdiri daripada molekul neutral TOTAL

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1 1 1 1

1 1

Max. = 10 20 SULIT

ANSWER SCHEME

Question 10 (a)

PPT KIMIA P2 TING. 4 (2018)

Answer

Marks

1. Electron arrangement of atom W is 2.8.1 Susunan elektron atom W ialah 2.8.1 // Atom W has one valence electron Atom W mempunyai satu elektron valens 2. Atom W donates / releases one electron Atom W menderma / melepaskan satu elektron 3. To achieve stable octet electron arrangement Untuk mencapai susunan elektron oktet yang stabil 4. Forming W+ (ion) Membentuk (ion) W+ 5. Electron arrangement of atom Z is 2.8.7 Susunan elektron atom Z ialah 2.8.7 Atom Z has seven valence electrons Atom Z mempunyai tujuh elektron valens 6. Atom Z accepts one electron Atom Z menerima satu elektron 7. Forming Z- (ion) Membentuk (ion) Z8. W+ and Z- are attracted by electrostatic force W+ dan Z- tertarik oleh daya elektrostatik 9. Forming ionic bond / compound with a formula of WZ Membentuk ikatan / sebatian ion dengan formula WZ 10. Correct diagram of W+ 11. Correct diagram of Z-

1 1 1 1

1 1

+ W

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Max. = 10

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ANSWER SCHEME (b)

(c)

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PPT KIMIA P2 TING. 4 (2018)

1. Correct formulae of reactant and products 2. Balanced equation Answer: Zn + H2SO4 → ZnSO4 + H2 3. Number of moles of Zn = 1.3 g // 0.02 mol -1 65 g mol 4. Ratio of moles 1 mol Zn : 1 mol H2 0.02 mol Zn : 0.02 mol H2 ecf P4 from P2 / P3 5. Volume of H2 = 0.02 mol × 22.4 dm3 mol-1 // 0.448 dm3 1. Named ionic compound : sodium chloride / natrium klorida // copper(II) sulphate / kuprum(II) sulfat // [any suitable ionic compound] 2. Named covalent compound : naphthalene / naftalena // sugar / gula / glukosa // [any suitable covalent compound] 3. Apparatus : crucible / mangkuk pijar, spatula / spatula, pipe clay triangle / segi tiga tanah liat, tripod stand / tungku kaki tiga, Bunsen burner / penunu Bunsen 4. Put one spatula of [sodium chloride] into a crucible Letakkan satu spatula [natrium klorida] ke dalam mangkuk pijar 5. Heat the [sodium chloride] Panaskan [natrium klorida] 6. Observe whether [sodium chloride] melts Perhatikan sama ada [natrium klorida] melebur // Record the observation Rekodkan pemerhatian 7. Repeat the experiment using [naphthalene] to replace [sodium chloride] Ulang eksperimen menggunakan [naftalena] untuk menggantikan [natrium klorida] 8. Sodium chloride does not melt easily [Natrium klorida] sukar untuk melebur

1 1

1 Total = 5 1

1 1 1

SULIT

ANSWER SCHEME

PPT KIMIA P2 TING. 4 (2018)

9. Sodium chloride has high melting point [Natrium klorida] mempunyai takat lebur yang tinggi 10. Naphthalene melts easily [Naftalena] melebur dengan mudah 11. Naphthalene has low melting point [Naftalena] mempunyai takat lebur yang rendah

1 1 1 Max. = 10 TOTAL

END OF MARKING SCHEME

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