Chemistry Spm Module

MODUL 1 paper 3 questions

1

1.

A student carried out two experiments to determine the concentration of HX acid solution. Seorang pelajar menjalankan dua eksperimen untuk menentukan kepekatan larutan asid HX. Experiment I Eksperimen I Titration of HX acid solution of unknown concentration with 20cm3 of sodium hydroxide solution 1.0 mol dm-3 using phenolftalein as indicator. Pentitratan larutan asid HX yang tidak diketahui kepekatannya dengan 20cm3 larutan natrium hidroksida 1.0 mol dm-3 menggunakan penunjuk fenolftalein. Experiment II Eksperimen II Titration of similar HX acid solution of difference concentration with 20cm3 of sodium hydroxide solution 1.0 mol dm-3 using phenolftalein as indicator. Pentitratan larutan asid HX lain yang tidak diketahui kepekatannya dengan 20cm3 larutan Natrium Hidroksida 1.0 mol dm-3 menggunakan penunjuk fenolftalein. Diagram 1 shows the initial and final burette readings for both experiments. Rajah 1 menunjukkan bacaan awal dan bacaan akhir buret bagi kedua-dua eksperimen. Experiment 1 Eksperimen 1

0

20

1

21

Initial burette reading Bacaan awal buret

Final burette reading Bacaan akhir buret

Experiment II Eksperimen II

2

15

25

16

26

Initial burette reading Bacaan awal buret

Final burette reading Bacaan akhir buret Diagram 1 Rajah 1

(a) Construct a table to record the initial and final burette readings and the volumes of the acid used for both experiments. Bina jadual dan catat bacaan awal dan bacaan akhir buret serta isipadu asid yang digunakan bagi kedua-dua eksperimen di atas.

[ 3 marks] (b) State the colour change of phenolftalein in the titration. Nyatakan perubahan warna fenolftalein dalam titratan tersebut. ………………………………………………………………………………………………….. [3 marks] (c) The chemical equation for the reaction in the experiment is : Persamaan kimia bagi tindak balas dalam eksperimen ini ialah : HX +

NaOH

NaX 3

+

H2O

Calculate the concentration of HX acid solutions used in both experiments. Hitung kepekatan larutan asid HX yang digunakan dalam kedua-dua eksperimen. Experiment I Eksperimen I

Experiment II Eksperimen II

[ 3 marks] (d) State the hypothesis in this experiment. Nyatakan hipotesis bagi eksperimen ini. ……………..………………………………………………………………………………….. .. ………………………………………………………………………………………………. [ 3 marks] (e) If HX acid is replaced with sulphuric acid of the same concentration, it is found that the volume of the sulphuric acid used in the titration is half of the volume of HX acid. Explain why. Jika asid HX digantikan dengan asid sulfurik yang mempunyai kepekatan yang sama, didapati isipadu asid sulfurik yang digunakan dalam titratan ialah separuh daripada isipadu asid HX. Terangkan mengapa. ………………………………………………………………………………………………….. ………………………………………………………………………………………………….. …………………………………………………………………………………………………. [ 3 marks]

2. An experiment was carried out to determine the freezing point of liqiud X. A boiling tube 4

contain molten X at 95 oC was allowed to cool in a conical flask to room temperature.The temperature of X was recorded every 30 seconds intervals. Figure 2 shows the reading of the thermometer for this experiment. Satu eksperimen telah dijalankan untuk menentukan takat beku cecair X. Satu tabung didih yang mengandungi leburan X pada suhu 95 oC diletakkan kelalang kon dan dibiarkan menyejuk dalam keadan suhu bilik. Suhu direkod setiap 30 saat.

FIGURE 2 (a) Record the temperature at each time interval in the spaces provided in Figure 2. Catatkan bacaan suhu bagi setiap sela masa dalam ruangan yang disediakan dalam rajah 2. [ 3 marks ]

5

(b) On the graph paper below, draw the graph of temperature against time for the cooling of X. Pada kertas graf di bawah, lukiskan graf suhu melawan masa bagi penyejukan X [ 3 marks ]

6

(c) On the graph in (b), determine the freezing point of X. Show on the graph how you determine this freezing point. Pada graf di(b) tentukan takat beku X. Tunjukkan pada graf bagaimana anda tentukan takat beku. [ 3 marks ] (d )

How does the graph in (b) show the freezing point of X ? Pada graf di(b) bagaimanakah ia menunjukkan takat beku X. ............................................................................................................................................... ............................................................................................................................................... [ 3 marks ]

(e) The temperature of X did not change from the 90th second until the 150th second during the cooling process. Expalain why. Suhu X tidak berubah dari saat ke 90 hingga saat ke 150 semasa process penyejukan. Terangkan mengapa. ............................................................................................................................................... . ............................................................................................................................................... . ............................................................................................................................................... . [ 3 marks ] (f)

Why was the boiling tube placed in the conical flask during the cooling process? Mengapakah tabung didih diletakkan dalam kelalang kon semasa proses penyejukan? ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ [ 3 marks ]

7

3. A student carried out an experiment to investigate the effect of heat on lead (II) nitrate and zinc carbonate salt. The released gas is passed through into the lime water. Figure 3 below shows the set-up of apparatus for heating lead(II) nitrate and zinc nitrate. Lead(II) carbonate Zinc carbonate (white solid)

(white solid)

Earlier experiment

Heat

Heat

Lime water

Lime water

Residue (brown solid)

Residue (yellow solid)

Final experiment Heat

Heat Lime water

Lime water

Figure 3 (a)

Complete the following table by stating the observations and related inferences for heating of lead(II) carbonate salt. Observations Inferences

i) ……………………………………...

i) ………………………………………...

……………………………………...

………………………………………..

ii) ……………………………………..

ii) ……………………………………….

8

……………………………………..

……………………………………….. [3 marks]

(b)

State the hypothesis for the experiment. ………………………………………………………………………………………….. [3 marks]

(c)

Write the chemical equation for the effect of heat on lead(II) carbonate. ……………………………………………………………………………………….… [3 marks]

(d)

The residue of heating lead(II) carbonate salt is dissolved in the dilute nitric acid. After that, the solution is added with the excess sodium hydroxide solution. State the observation. …………………………………………………………………………………………… …………………………………………………………………………………………… [3 marks]

(e)

2.67 g of lead(II) carbonate decomposed completely when it is heated. Calculate the number of moles of gas released. [ Relative molecular mass of lead(II) carbonate, 267]

[3 marks] (f)

Name the products when zinc carbonate is heated. …………………………………………………………………………………………… [3 marks]

9

4.

A student is given an ionic compound X and covalent compound Y.

Using the suitable materials and apparatus, plan a labotary experiment to compare the electrical conductivity between the compounds of X and Y. Your explaination should include all the followings: (a) (b) (c) (d) (e)

Statement of the problem All the variables List of materials and apparatus Procedure Tabulation of data [ 17 marks ]

10

MODUL 2 SOLVING NUMERICAL PROBLEMS INVOLVING CHEMICAL EQUATION

Things to remember !!! (A) 11

IONIC FORMULAE

Cations (+)

Anions (-) Mass ( g ) Molarmass

(B)

No. of moles =

(C)

No. of particles = No. of moles x NA

(D)

Volume of gas = No. of moles x Molar volume

(E)

No. of moles =

MV 1000

Notes (i) Molar mass = relative atomic mass or relative molecular mass of the substance (ii) NA = Avogadro constant, 6.02 x 1023 (iii) Molar volume = 22.4 dm3 at STP or 24 dm3 at room conditions

NUMERICAL PROBLEMS INVOLVING CHEMICAL EQUATIONS Step 1 : Write a balanced chemical equation Step 2 : Identify substances involved in the calculation, A and B Step 3 : Convert the given information (mass/volume of gas/number of particles) of A

12

into the number of moles Step 4 : Compare the mole ratio of A and B from the chemical equation Step 5 : Calculate the number of moles of B based on the mole ratio in the equation Step 6 : Convert the number of moles of B to the unit required in the question

Mass (g)

÷ RAM @ RMM

Concentration of solution (mol/dm3) and volume

x RAM @ RMM

n = MV 1000

x 24 dm3 @ 22.4 dm3 Volume of gas

NO. OF MOLES ÷ 24 dm3 @ 22.4 dm3

x NA

÷ NA

No. of particles

EXAMPLE 1 Calculate the mass of zinc required to react with excess hydrochloric acid to produce 6 dm 3 of hydrogen gas at room conditions. [RAM: Zn,65; Cl,35.5; Molar volume: 24 dm3mol-1 at room conditions] 13

Step 1 :

Zn + 2HCl → ZnCl2 + H2

Step 2 :

mass?

Step 3 :

No. of moles of H2

6 dm3 = 6 dm3 24 dm3

= 0.25 mol ≡ 1 mol of Zn

Step 4 :

1 mol of H2

Step 5 :

0.25 mol of H ≡ 0.25 mol of Zn

Step 6 :

Mass of Zn

= 0.25 x 65 = 16.25 g

EXAMPLE 2 0.46 g of sodium burns completely in chlorine gas at room conditions. Find the volume of chlorine gas. [RAM: Na, 23; Molar volume: 24 dm3 mol-1 at room conditions] Step 1 :

2Na + Cl2 → 2NaCl

Step 2 :

0.46g

Step 3 :

No. of moles of Na = 0.46 23 = 0.02 mol

Step 4 :

2 mol of Na

Step 5 :

0.02 mol of Na ≡ 0.01 mol of Cl2

Step 6 :

Volume of Cl2 = 0.01 x 24 = 0.24 dm3

volume?

≡ 1 mol of Cl2

EXERCISES 1. 2.3 g of element X reacted completely with oxygen. The following equation represents the reaction.

14

4X + O2 → 2X2O Calculate the maximum mass of X2O formed. [Relative atomic mass: X=23, O=16]

2. Silver chloride decomposed when it is strongly heated according to equation below: 2AgNO3 → 2Ag + 2NO2 + O2 In an experiment, a student heated 85 g of silver nitrate. Calculate the volume of nitrogen dioxide released at room condition. [Relative atomic mass: N=14, O=16, Ag=108; 1 mol gas occupies 24.0 dm3 at room condition]

3. 3.2 g of copper (II) oxide powder is reacted with excess dilute nitric acid. Calculate the mass of copper (II) nitrate formed in the reaction. [Relative atomic mass: N=14, O=16, Cu=64]

4. Magnesium metal is burnt completely in air to produce 4.0 g magnesium oxide. Calculate the mass of magnesium required in the reaction above. [Relative atomic mass : Mg=24, O=16]

15

5. When 10 cm3 of 0.5 mol dm-3 sodium sulphate solution is added to excess lead (II) nitrate solution, a white precipitate is formed. Calculate the mass of precipitate formed. [Relative atomic mass: O=16, S=32, Pb=207]

6. Excess calcium carbonate reacts with 25 cm3 of 0.15 mol dm-3 hydrochloric acid. Calculate the volume of carbon dioxide gas released at room conditions. [Molar volume: 24 dm3 mol-1 at room condition]

16

MODUL 3 Atomic structure and chemical formulae and equations

1. The following is information about substance X. Maklumat berikut ialah tentang bahan X • • •

Solid at room temperature Pepejal pada suhu bilik Melting point is 80 0C Takat lebur ialah 80 0C Highly flammable. Mudah terbakar

17

In an experiment to determine the melting point of substance X, a boiling tube containing solid X is heated using a water bath until its temperature is above its melting point. Dalam satu eksperimen untuk menentukan takat lebur bagi bahan X , tabung didih yang mengandungi pepejal X dipanaskan menggunakan kukus air sehingga suhunya di atas takat lebur. (a)

Draw and label a diagram of apparatus that is used in the experiment. Lukis dan labelkan gambar rajah susunan radas yang digunakan dalam eksperimen itu

[ 2 marks] (b)

What is meant by melting point? Apakah yang dimaksudkan dengan takat lebur? ……………………………………………………………………………………………… [ 1 mark]

(c ) What is the purpose of using water bath in the experiment? Apakah tujuan menggunakan kukus air dalam eksperimen itu. ……………………………………………………………………………………………… [ 1 mark]

(d) Draw the arrangement of particles of substance X at 400C and 900C respectively. Lukiskan susunan zarah bagi bahan X pada suhu 400C and 900C masing-masing.

40 0 C

90 0 C 18

[ 2 marks] (e)

Sketch a graph of temperature against time during the heating. Mark on the graph to indicate the melting point of substance X. Lakarkan graf suhu melawan masa semasa pemanasan. Tandakan pada graf untuk menunjukkan takat lebur bahan X.

[ 3 marks] (f)

Suggest the name of substance X. Cadangkan nama bahan X. ……………………………………………………………………………………………… [ 1 mark]

2. Table 2 shows proton number and nucleon number for atom W, X and Y. Jadual 2 menunjukkan nombor proton dan nombor nukleon bagi atom W, X dan Y.

19

Atom W

Proton number / Nombor Proton 11

Nucleon number / Nombor Nukleon 23

X

17

35

Y

17

37

TABLE / JADUAL 2 (a)

(i)

What is meant by proton number? Apakah yang dimaksudkan dengan nombor proton ? ...........................................………………………………....................................... [1 mark]

(ii)

What is the number of neutron in atom W ? Apakah bilangan neutron dalam atom W? .........................................………………………………………............................. [1 mark]

(b) Which atoms are isotopes? Explain why. Atom – atom yang manakah adalah isotop? Jelaskan mengapa. ............................................................................................................................................... ............................................................................................................................................... [2 marks] (c) Write the electron arrangement of atom X . Tuliskan susunan elektron bagi atom X. .............................................................................................................................................. [1 mark] (d) (i)

Draw the electron arrangement of atom Y. In your diagram , show the number of proton and the number of neutron in the nucleus. Lukiskan susunan elektron atom Y. Dalam rajah anda, tunjukkan bilangan proton dan bilangan neutron dalam nukleus.

[2 marks] (ii)

What is the number of valence electron of atom Y? Apakah bilangan elektron valen bagi atom Y?

20

.................................................................................................................................. [1 mark] (iii) Write the formula of ion Y. Tuliskan formula ion Y. ........................................................................................... ....................................... [1 mark] (e)

Write the symbol of atom X in the form of Tuliskan simbol bagi atom X dalam bentuk

A Z

A Z

X.

X.

............................................................................................................................................... [1 mark] 3. Diagram 3 shows an experiment to determine the empirical formula of copper (II) oxide. Rajah 3 menunjukkan satu eksperimen untuk menentukan formula empirik kuprum (II) oksida. Copper(II) oxide Combustion tube Kuprum(II) oksida Tiub pembakaran Hydrogen flame Hydrogen gas Nyalaan hidrogen Gas hidrogen Dilute hydrochloric acid Asid hidroklorik Asbestos paper cair Kertas asbestos Heat Panaskan

Zinc pieces Ketulan zink Result : Keputusan :

Anhydrous calcium chloride Kalsium klorida kontang DIAGRAM / RAJAH 3

Mass of combustion tube + asbestos paper Jisim tiub pembakaran + kertas asbestos

= 58.36 g

Mass of combustion tube + asbestos paper + copper (II) oxide Jisim tiub pembakaran + kertas asbestos+ kuprum (II) oksida

= 91.96 g

Mass of combustion tube + asbestos paper + copper Jisim tiub pembakaran + kertas asbestos+ kuprum (a) What is meant by empirical formula? Apakah yang dimaksudkan dengan formula empirik?

21

= 85.24 g

……………………………………………………………………………………………… [1 mark] (b)

What is the function of anhydrous calcium chloride? Apakah fungsi kalsium klorida kontang? ……………………………………………………………………………………………… [1 mark]

(c)

How to ensure that the combustion tube has been totally filled with hydrogen gas? Bagaimana untuk memastikan bahawa tiub pembakaran telah dipenuhi dengan gas hidrogen? ……………………………………………………………………………………………… ……………………………………………………………………………………………… [2 marks]

(d)

Based on the above results, Berdasarkan keputusan di atas, (i) Calculate the mass of copper and the mass of oxygen that have reacted. Hitungkan jisim kuprum dan jisim oksigen yang bertindak balas.

[1 mark] (ii)

Calculate the mole ratio of copper atoms to oxygen atoms. Hitungkan nisbah mol bagi atom kuprum kepada atom oksigen. [ Relative atomic mass / Jisim atom relatif : O = 16 ; Cu = 64 ]

[1 mark]

22

(iii)

Determine the empirical formula of copper (II) oxide. Tentukan formula empirik kuprum (II) oksida. …………………………………………………………………………………….. [1 mark]

(iv)

Write the chemical equation for the reaction in the experiment. Tulis persamaan kimia bagi tindak balas dalam eksperimen tersebut. …………………………………………………………………………………….. [1 mark]

(e) Does this method suitable to determine the empirical formula of aluminium oxide? Explain your answer. Adakah kaedah ini sesuai untuk menentukan formula empirik bagi aluminium oksida. Jelaskan jawapan anda. ……………………………………………………………………………………………… ……………………………………………………………………………………………… [2 marks] 4. The following equation is not balanced : Persamaan berikut adalah tidak seimbang :

Na2SO4

+

BaCl2

BaSO4

+

NaCl

(a) Identify the reactants and products of the reaction. Kenal pasti bahan tindak balas dan hasil tindak balas bagi tindak balas tersebut. Reactants/Bahan tindak balas : …………………………………………………………… Products/Hasil tindak balas : ……………………………………………………………. [ 2 marks] (b) Write the balanced equation. Tuliskan persamaan yang seimbang ……………………………………………………………………………………………... [ 1 mark]

(c) Calculate/Hitungkan :

23

(i) the number of mole of sodium sulphate that react completely with a solution containing 4.16 g of barium chloride [ Relative atomic mass : Cl = 35.5; Ba = 137 ] bilangan mol natrium sulfat yang bertindak balas lengkap dengan suatu larutan yang mengandungi 4.16 g barium klorida [Jisim atom relatif : Cl = 35.5; Ba = 137 ]

[ 2 marks] (ii) the mass of barium sulphate formed when 1 mol of sodium sulphate is reacted completely with barium chloride. [ Relative atomic mass : O = 16; S = 32; Ba = 137 ] Jisim barium sulfat yang terbentuk apabila 1 mol natrium sulfat bertindak balas lengkap dengan barium klorida. [Jisim atom relatif : O = 16; S = 32; Ba = 137 ]

[ 2 marks] (d) In an experiment, when chlorine gas is passed over heated iron wool, a chloride compound with 34.5 % iron by mass is formed. Determine the empirical formula of the chloride compound. [ Relative atomic mass : Cl = 35.5; Fe = 56 ] Dalam satu eksperimen, apabila gas klorin dialirkan melalui wul besi yang panas, suatu sebatian klorida yang mengandungi 34.5% besi mengikut jisim terbentuk. Tentukan formula empirik bagi sebatian klorida tersebut. [Jisim atom relatif : Cl = 35.5; Fe = 56 ]

24

5. (a)

Table 5 shows empirical formula and molecular formula for ethene. Jadual 5 menunjukkan formula empirik dan formula molekul bagi etena.

Empirical Formula

Molecular Formula

Formula Empirik

Formula Molekul

CH2

C2H4 Table / Jadual 5

Based on the information in Table 7.1, compare and differentiate between empirical formula and molecular formula.of ethene in terms of type of element, number of atom for each element and its relative molecular mass. [Relative atomic mass : C = 12 ; H = 1] Berdasarkan maklumat dalam Jadual 7.1, banding dan bezakan formula empirik dan formula molekul etena dari segi jenis unsur, bilangan atom setiap unsur dan jisim molekul relatif masing-masing. [Jisim atom relatif : C = 12 ; H = 1] [ 3 marks] (b) Diagram 5 shows the set up of apparatus that a student used to determine the empirical formula of L oxide. L is situated below hydrogen in the Reactivity Series. Rajah 5 menunjukkan susunan radas yang digunakan oleh seorang pelajar untuk menentukan formula empirik satu oksida L. L berada di bawah hidrogen dalam Siri Kereaktifan.

Excess hydrogen flame Nyalaan hidrogen berlebihan

Combustion tube Tabung pembakaran

Dry hydrogen gas Gas hidrogen kering

L oxide Oksida L Porcelain dish Piring porselin

Heat

Diagram / Rajah 5

25

The result for above experimet is as the following: Keputusan yang diperoleh dalam eksperimen adalah seperti berikut : Mass of combustion tube + porcelain dish Jisim tabung pembakaran + piring porselin

=

52.45 g

Mass of combustion tube + porcelain dish Jisim tabung pembakaran + piring porselin + oksida logam L

=

105.97 g

Mass of combustion tube + porcelain dish Jisim tabung pembakaran + piring porselin + logam L

=

102.13 g

Table / Jadual 5 (i)

Based on the information in Table 7.3, determine the empirical formula of L oxide. Berdasarkan maklumat di atas tentukan formula empirik bagi oksida L [Relative atomic mass / jisim atom relatif : L = 207, O = 16] [3 marks]

(ii)

Write the chemical equation for the reaction occurred. Tuliskan persamaan kimia bagi tindak balas yang berlaku. [2 marks]

(iii)

How do you know that the air in the combustion tube has been removed completely before heating? Bagaimanakah anda tahu bahawa semua udara telah disingkirkan daripada tabung pembakaran sebelum pemanasan? [3 marks]

(iv)

Table 7.4 shows the metals and suitable method to determine their metal oxide empirical formula. Jadual 7.4 menunjukkan logam-logam dan kaedah yang sesuai untuk menentukan formula empirik oksida logam masing-masing. Metal Logam

Method Kaedah

L and copper L dan kuprum

Dry hydrogen gas is flow to hot metal oxide. Gas hidrogen kering dialirkan pada oksida logam yang panas. Metal is burnt in air. Logam dibakar dalam udara.

Magnesium

Table / Jadual 7.4 Explain why the methods are different? Terangkan mengapa terdapat perbezaan kaedah itu? [2 marks]

26

2H2(g) + O2(g)

(c)

2H2O(ℓ)

(i) State three informations that you can predict from the above equation. Nyatakan tiga malumat yang anda dapat tafsirkan daripada persamaan di atas. [3 marks] (ii)

Based on the equation, calculate the volume of oxygen gas needed to produce 18 g of water at STP. Berdasarkan persamaan kimia di atas, hitungkan isipadu gas oksigen pada STP yang diperlukan untuk menghasilkan 18 g air. [Relative atomic mass / Jisim atom relatif : H = 1, O = 16 ] [Molar volume of gas at STP / Isipadu molar gas pada STP = 22.4 dm3] [4 marks]

27

MODUL 4 Periodic table and chemical bonds

28

1. Diagram 1 shows the symbols of atom for element U, V, W and X. Rajah 1 menunjukkan simbol- simbol atom bagi unsur U, V, W dan X.

7 3

U

12 6

V

19 9

W

20 10

X

DIAGRAM / RAJAH 1 (a) Write the electron arrangement of atom W. Tuliskan susunan elektron bagi atom W. ......................................................................................................................................... ....... [1 mark] (b) (i)

Element U, V, W and X are placed in the same period in the Periodic Table. State the period. Unsur U, V, W dan X berada dalam kala yang sama dalam Jadual Berkala. Nyatakan kala itu. .................................................................................................................................. [1 mark]

(ii)

Compare the atomic size of element V and X. Bandingkan saiz atom unsur V dan X. .................................................................................................................................. [1 mark] (iii)

Explain your answer in (b) (ii) Terangkan jawapan anda dalam (b) (ii). ..................................................................................................................................

. .................................................................................................................................. . [2 marks ] (c) Element V can react with element W to form a compound. Unsur V boleh bertindak balas dengan unsur W membentuk satu sebatian. (i)

Write the chemical formula for the compound. Tuliskan formula kimia bagi sebatian itu. .................................................................................................................................

29

[1 mark ] (ii)

State one physical property for the compound formed. Nyatakan satu sifat fizikal bagi sebatian yang terbentuk. ……………………………………………………………………………............... [1 mark ]

(d) When element U react with element W, a compound is produced. Apabila unsur U bertindak balas dengan unsur W, satu sebatian terhasil. (i)

State the type of the compound produced. Nyatakan jenis sebatian yang terhasil. ………...................................................................................................................... [1 mark ]

(ii)

Draw the electron arrangement for the compound in (d) (i). Lukiskan susunan elektron bagi sebatian dalam (d) (i).

[2 marks] 2. Table 2 shows the proton number of a few elements in Period 3. Jadual 2 menunjukkan nombor proton bagi sebahagian unsur dalam Kala 3. Element Unsur

Sodium

Magnesium

Aluminium

Chlorine

Argon

11

12

13

17

18

Proton number Nombor proton

TABLE / JADUAL 2 Based on Table 2, answer the following questions : Berdasarkan Jadual 2, jawab soalan-soalan berikut : (a)

Name two metals. Namakan dua logam. …………………………………………………………………………………………

…… [1 mark] 30

(b)

Chlorine is in the group 17 in the Periodic Table. What is another name for group 17? Klorin terletak dalam Kumpulan 17 dalam Jadual Berkala. Apakah nama lain bagi kumpulan 17? ……………………………………………………………………………………………… [1 mark]

(c)

Write the electron arrangement of aluminium atom. Tuliskan susunan elektron bagi atom aluminium. ……………………………………………………………………………………………… [1 mark]

(d)

(i)

Arrange the element in Table 2 according to their atomic sizes in descending order. Susunkan unsur dalam Jadual 2 mengikut susunan menurun saiz atom. …………………………………………………………………………………….. [1 mark]

(ii)

Explain your answer in (d) (i). Terangkan jawapan anda di (d) ……………………………………………………………………………………. …………………………………………………………………………………….. [2 marks]

(e)

When sodium is burnt in chlorine, sodium chloride is formed. Apabila natrium dibakar dalam klorin, natrium klorida terbentuk. (i)

(ii)

State one observation. Nyatakan satu pemerhatian …………………………………………………………………………………….. [1 mark] Write the chemical equation for the reaction. Tuliskan persamaan kimia bagi tindak balas itu. …………………………………………………………………………………….. [2 marks]

(iii)

State one physical property of sodium chloride. Nyatakan satu sifat fizik bagi natrium klorida. …………………………………………………………………………………….. [1 mark]

31

3. Figure 3 shows the symbol for an atom of element X and an atom of element Y Rajah 3 menunjukkan simbol bagi atom unsur X dan atom unsur Y .

23

35

X

Y

11

17 FIGURE / RAJAH 3

Based on Figure 3, answer the following questions. Berdasarkan Rajah 3 , jawab soalan-soalan berikut. (a)

(i)

Write the electron arrangement for an atom of element X . Tuliskan susunan elektron bagi atom unsur X. .................................................................................................................................. [ 1 mark ] State the group of element X in Periodic Table. Nyatakan kumpulan bagi unsur X dalam Jadual Berkala

(ii)

..................................................................................................................... [ 1 mark ] (iii)

State the period of element X in Periodic Table.Explain your answer. Nyatakan kala bagi unsur X dalam Jadual Berkala.Terangkan jawapan anda. .................................................................................................................................. .................................................................................................................................. [ 2 marks ]

(b)

(i)

What is the number of neutron in an atom of element Y. Berapakah bilangan neutron dalam atom unsur Y .................................................................................................................................. [ 1 mark]

(ii)

Write the formula for the ion formed from an atom of element Y. Tuliskan formula ion yang terbentuk daripada atom unsurY. .................................................................................................................................. [ 1 mark ]

32

(c )

(i)

Draw the electron arrangement of compound formed from the reaction of element X and element Y. Lukiskan susunan elektron bagi sebatian yang terbentuk daripada unsur X dengan unsur Y.

[ 2 marks ] (ii)

State the type of bond formed between element X and element Y. Nyatakan jenis ikatan yang terbentuk antara unsur X dan unsur Y. .................................................................................................................................. [ 1 mark ]

(iii)

State one property of the compound formed between element X and element Y. Nyatakan satu sifat fizik sebatian yang terbentuk itu antara unsur X dan unsur Y. .................................................................................................................................. [ 1 mark ]

33

4. Table 4 shows the electron arrangement of atom of element R, Q and Z. Jadual 4 menunjukkan susunan elektron bagi atom unsur R, Q dan Z. Element Unsur

Electron arrangement Susunan elektron

R Q Z

2.8.2 2.8.4 2.8.7 TABLE / JADUAL 4

(a)

State the Period of the elements R, Q and Z in the Periodic Table? Explain your answer. Nyatakan Kala bagi unsur R , Q dan Z dalam Jadual Berkala. Terangkan jawapan anda. [2 marks]

(b)

24

The R atom is represented as

.R

12

Draw the electron arrangement of the atom of element R. In your drawing, show the number of proton and neutron. Atom R diwakili sebagai

.

24 12

R

Lukiskan susunan elektron bagi atom unsur R. Dalam lukisan anda, tunjukkan bilangan proton dan neutron. [2 marks] (c )

Based on Table 9, explain in terms of electron arrangement Berdasarkan Jadual 9, terangkan dari segi susunan elektron (i)

how atoms R and Z form a compound. bagaimana atom R dan Z membentuk sebatian.

(ii)

how atoms Q and Z form a compound. bagaimana atom Q dan Z membentuk sebatian. [8 marks]

34

MODUL 5 electrochemistry

35

1. Figure 1.1 shows the set-up of apparatus to investigate the electrolysis of 1.0 mol dm -3 copper(II)sulphate solution using carbon electrode. Rajah 1.1 menunjukkan susunan radas untuk mengkaji elektrolisis larutan kuprum(II) sulfat 1.0 mol dm-3 menggunakan elektrod karbon.

1.0 moldm -3 copper(II)sulphate

Carbon electrode U

Carbon electrode T

A FIGURE / RAJAH 1.1 (a) (i)

What is meant by electrolysis? Apakah yang dimaksudkan dengan elektrolisis ? ………………………………………………………………….............................. [1 mark]

(ii)

What is the energy change that occurs in the electrolysis process? Apakah perubahan tenaga yang berlaku dalam proses elektrolisis. …………………………………………………………………………………….. [1 mark ]

(b) State all the ions present in copper (II) sulphate solution. Nyatakan semua ion yang hadir dalam larutan kuprum(II)sulfat. ……………………………………………………………………………………… ……... [1 mark ] (c )

(i)

State an observation at electrode T. Nyatakan satu pemerhatian di elektrod T. 36

…………………………………………………………………………… ……….. [ 1 mark ] (ii)

Write the half equation of the reaction at electrode T. Tuliskan setengah persamaan bagi tindak balas yang berlaku di elektrod T. .................................................................................................................................. [ 1 mark ]

(d )

What is the colour change of the copper (II) sulphate solution?Explain your answer. Apakah perubahan yang berlaku kepada warna larutan kuprum(II)sulfat?Terangkan jawapan anda. ...............................................................................................................................................

. ............................................................................................................................................... . [ 2 marks ] (e)

(i)

Name the gas collected in the test tube at electrode U. Namakan gas yang terkumpul dalam tabung uji di elektrod U. .................................................................................................................................. [ 1 mark ]

(ii)

The volume of gas collected at electrode U is 15.0cm3. How many moles of the gas were collected? Use the information that 1 mole of gas occupies a volume of 24.0 dm3 at room temperature and pressure. Isipadu gas yang dikumpul di elektrod U ialah 15.0cm3. Berapakah bilangan mol gas yang terbebas. Gunakan maklumat 1 mol gas menempati isipadu 24.0 dm3 pada suhu dan tekanan bilik

[ 1 mark] (f) An experiment has been carry out to investigate the position of copper in electrochemical series using set-up of apparatus as in figure 1.2. Satu eksperimen lain telah dijalankan untuk mengkaji kedudukan kuprum dalam Siri Elektrokimia menggunakan susunan radas seperti Rajah 1.2. V . Metal plate /kepingan logam

Copper plate / kepingan kuprum 37 Copper(II)nitrate solution / Larutan kuprum(II) nitrat

FIGURE / RAJAH 1.2 If the metal plate is replaced by metal X ,Y and Z that are dipped consecutively, the potential difference produced is shown in Table 1.1. Jika kepingan logam digantikan dengan logam X , Y dan Z yang dicelupkan secara berasingan, beza keupayaan yang terhasil ditunjukkan dalam Jadual 1. Metal plate Kepingan logam X Y Z

Potential difference (V) Beza keupayaan (V)

Positive terminal Terminal positif

0.5 1.2 2.7 Table / Jadual 1.1

Copper / Kuprum Copper / Kuprum Copper / Kuprum

Based on the result, arrange metals copper, X, Y and Z in descending order of electropositivity of metals. Berdasarkan keputusan di atas, susunkan logam-logam kuprum , X ,Y dan Z mengikut susunan tertib menurun keelektropositifan logam. ............................................................................................................................................... . [ 1 mark ] 2. The Figure 2 shows a simple chemical cell. Rajah 1.3 menunjukkan sebuah sel kimia ringkas.

v Copper electrode Elektrod kuprum

Electrode R Elektrod R

Copper(II) sulphate solution Larutan kuprum(II) sulfat Figure / Rajah 2 Table 2 shows the voltage value and the positive terminal when different metals are used as the electrode R.

38

Jadual 2 menunjukkan nilai voltan dan kutub positif apabila logam berlainan digunakan sebagai elektrod R. Metal Logam

Voltage value (V) Nilai voltan (V)

Positive terminal Kutub positif

V

1.1

Copper / Kuprum

W

2.7

Copper / Kuprum

X

0.5

Copper / Kuprum

Y

0.8

Copper / Kuprum

Z

0.0

Table / Jadual 2

(a)

State the energy change that occurred in the chemical cell. Nyatakan perubahan bentuk tenaga yang berlaku dalam sel ringkas itu. …………………………………………………………………………………………

…… [1 mark] (b)

(i)

State all the ions presence in copper(II) sulphate solution. Nyatakan semua ion yang terdapat dalam larutan kuprum(II) sulfat. …………………………………………………………………………………...... [1 mark]

(ii)

The colour of the copper(II) sulphate is blue. State the ion in (b) (i) that gives the colour of the solution. Larutan kuprum(II) sulfat berwarna biru. Nyatakan ion di (b) (i) yang memberikan warna biru itu kepada larutan tersebut. …………………………………………………………………………………...... [1 mark]

(c) Based on the simple cell using copper metal and V, Berdasarkan sel ringkas yang menggunakan logam kuprum dan V, (i)

State the direction of electron flow Nyatakan arah pengaliran electron …………………………………………………………………………………...... [1 mark]

(ii)

Explain your answer in (c) (i) Terangkan jawapan anda di (c) ……………………………………………………………………………….......... [1 mark] 39

(iii)

State the observation at copper electrode. Nyatakan pemerhatian di elektrod kuprum. ……………………………………………………………………………….......... [1 mark]

(iv)

Write the half equation to that occured at copper electrode. Ttuliskan setengah persamaan bagi mewakili tindak balas yang berlaku di elektrod kuprum. …………………………………………………………………………………...... [1 mark]

(d) (i)

Arrange metals V, W, X and Y in the electrochemical series in descending order. Susunkan logam-logam V, W, X dan Y dalam siri elektrokimia mengikut tertib menurun. …………………………………………………………………………………...... [1 mark]

(ii)

If metal X and metal Y are used as the electrodes in simple cell in Diagram 2, suggest the possible voltage value of the cell. Jika logam X dan logam Y dijadikan sebagai elektrod-elektrod dalam sel ringkas pada Rajah 2, cadangkan nilai voltan yang mungkin sel ringkas itu. ……………………………………………………………………………….......... [1 mark]

(iii)

Predict metal Z. Ramalkan logam Z. ……………………………………………………………………………….......... [1 mark]

3. Diagram 3 shows two types of cells, cell A and cell B. Rajah 3 menunjukkan dua jenis sel , sel A dan sel B. Zinc Zink

40

Copper Kuprum

Copper(II) sulphate solution Larutan Kuprum(II) sulfat Cell A Sel A

Cell B Sel B DIAGRAM/RAJAH 3

(a)State the energy change in cell A. Nyatakan perubahan tenaga dalam sel A . …...…………………………………………………………………………………………. [ 1 mark ]

(b) Mark / Tandakan (i) the positive and negative terminal on the electrode in cell A terminal positif dan terminal negatif pada elektrod dalam sel A [ 1 mark ] (ii)

the direction of electron flow in cell B by drawing an arrow. arah pengaliran elektron dalam sel B dengan melukis anak panah . [ 1 mark ]

(c) Zinc in cell B acts as anode. Explain why. Zink dalam sel B bertindak sebagai anod.Terangkan mengapa. ……………………………………………………………………………………………… [ 1 mark ] (d) Referring to the positive electrode of cell A, Dengan merujuk kepada elektrod positif sel A, (i)

state the observation you would expect. nyatakan pemerhatian yang anda jangkakan. ………….……………………………………………………………………

……. [ 1 mark ]

41

(ii)

Write the half equation for the reaction. Tuliskan setengah persamaan bagi tindak balas yang berlaku. ………….……………………………………………………………………

……. [ 1 mark ] (e) Explain what will happen to the concentration of copper(II) sulphate solution in cell A. Terangkan apa yang berlaku pada kepekatan larutan kuprum(II)sulfat dalam sel A. ………………………..……………………………………………………………………. ……………………………………………………………………………………………… [ 2 marks ] (f) (i) The voltage for the pair of copper and zinc metal in cell B is 1.1 V. Predict the voltage if zinc metal is replaced by magnesium metal. Bacaan voltan bagi pasangan logam kuprum dan zink dalam sel B ialah 1.1V. Ramalkan bacaan voltan sekiranya logam zink digantikan dengan logam magnesium. ………………………………………………………………………………… ….. [ 1 mark ] (ii)

Explain your answer in (f) (i). Terangkan jawapan anda di (f) (i). ..…………………………………………………………………………………… [ 1 mark ]

42