ujian penilaian 1 f5 2012

7/28/2019 ujian penilaian 1 f5 2012

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Section A

Bahagian A

[60 marks]

[60 markah]

Answerall questions in this section.Jawab semua soalan dalam bahagian ini.

1 The following diagram shows a flow chart that identifies the cation and anion of an

unknown compound.

Gambar rajah yang berikut menunjukkan sebuah carta yang mengenal pasti kation dananion suatu sebatian X.

(a) (i) The preliminary examination of compound Xshows that it is a


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green crystalline solid. Name two metal ions that are green.

Pemeriksaan awal sebatian X menunjukkan bahawa ia adalah

pepejal hijau. Namakan dua ion logam yang berwarna hijau.

.

[1 mark][1 markah]

(ii) CompoundXdissolves in water to produce a green solution. What

inference can be made with regards to the anion of compoundX?

Sebatian X dilarutkan ke dalam air untuk menghasilkan larutanhijau. Apakah inferens yang boleh dibuat dengan merujuk kepada

anion sebatian X?

.

[1 mark]

[1 markah]

(b) (i) When dilute sodium hydroxide is added to solutionX, a greenprecipitate is formed which is insoluble in excess sodium hydroxide

solution. What inference can be made about the cation in compound

X?Apabila natrium hidroksida cair ditambahkan ke dalam larutan X,

satu mendakan hijau terbentuk dan ia tak larut dalam larutan

nartrium hidroksida berlebihan. Apakah inferens yang boleh dibuat

tentang kation sebatian X?

.

[1 mark][1 markah]

(ii) The test is repeated with dilute ammonia solution, a green

precipitate is formed which is also insoluble in excess ammonia

solution. What inference can be made about the cation in compoundX?

Ujian tersebut diulangi dengan larutan ammonia cair, mendakan

hijau terbentuk dan ia juga tak larut dalam larutan ammonia cairberlebihan. Apakah inferens yang boleh dibuat tentang kation

dalam sebatian X?

.[1 mark]

[1 markah]

(c) Describe one confirmatory test for the cation in compoundX.Gambarkan satu ujian pengesahan bagi kation dalam sebatian X.


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[2 marks]

[2 markah]

(d) (i) When dilute nitric acid is added to solutionX, no effervescence isobserved. What inference can be made from the observation?

Apabila asid nitrik cair ditambah ke larutan Y, tiada pembuakan

diperhatikan. Apakah inferens yang oleh dibuat berdasarkanpemerhatian tersebut?

.

[1 mark][1 markah]

(ii) A white precipitate is produced when silver nitrate solution is added

to the mixture of solutionXand nitric acid. What inference can bemade from the reaction?

Satu mendakan putih telah dihasilkan apabila larutan argentum

nitrat telah dicampurkan dengan campuran larutan X dan asid

nitrik. Apakah inferens yang boleh dibuat daripada tindak balastersebut?

.

[1 mark]

[1 markah]

(iii) The test is repeated with barium nitrate solution. No precipitate is

formed. What inference can be made for the observation?Ujian tersebut diulangi dengan larutan barium nitrat. Tiada

mendakan yang terbentuk. Apakah inferens yang boleh dibuat

daripada pemerhatian tersebut?

.

[1 mark]

[1 markah]

(e) Name compoundX.

Namakan sebatian X.

[1 mark]

[1 markah]

2 Two experiments is conducted to investigate the rate of decomposition of hydrogenperoxide is as shown below.

Dua eksperimen dijalankan untuk menyiasat tentang kadar penguraian hidrogen

peroksida seperti yang ditunjukkan di bawah.

Experiment I

Eksperimen I


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20 cm3 of 0.1 mol dm3 hydrogen peroxide is put into a conical flask and 3 g

of manganese(IV) oxide is added.20 cm3 hidrogen peroksida 0.1 mol dm3diletakkan ke dalam kelalang kon

dan 3 g mangan(IV) oksida ditambahkan ke dalamnya.

Experiment II

Eksperimen II20 cm3 of 0.4 mol dm3 hydrogen peroxide is put into a conical flask and 3 g

of manganese(IV) oxide is added.

20 cm3 hidrogen peroksida 0.4 mol dm3 diletakkan ke dalam kelalang kondan 3 g mangan(IV)oksida ditambahkan ke dalamnya.

(a)

Suggest one method of collecting the volume of gas given out for the two

experiments.

Cadangkan satu kaedah untuk mengumpulkan isi padu gas yang telah

dibebaskan bagi kedua-dua eksperimen berkenaan.

.

.

[1 mark]

[1 markah]

(b)

Draw the set-up of the apparatus used to collect the released gas.

Lukiskan susunan radas yang digunakan untuk pengumpulan gas tersebut.

[2 marks]

[2 markah]

(c)

Write an equation for the decomposition of hydrogen peroxide.

Tuliskan satu persamaan bagi penguraian hidrogen peroksida.

..

[1 mark]

[1 markah]

(d)From the experiments, which experiment has a higher rate ofdecomposition of hydrogen peroxide?

Daripada eksperimen-eksperimen di atas, eksperimen yang manakah

menpunyai kadar penguraian hidrogen peroksida yang lebih tinggi?


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...........

[1 mark]

[1 markah]

(e) Explain your answer in (d).

Jelaskan jawapan anda di (d).

...........

[1 mark][1 markah]

(f) What is the function of manganese(IV) oxide in the experiments?

Apakah fungsi mangan(IV) oksida di dalam eksperimen?

...........[1 mark]

[1 markah]

(g) Explain the role of manganese(IV) oxide in raising the rate of reaction,according to the theory of collision of particle.

Jelaskan peranan mangan(IV) oksida dalam meningkatkan kadar tindak

balas dengan berpandukan teori perlanggaran zarah.

...........

[1 mark]

[1 markah](h) Sketch the graph of volume of oxygen gas collected against the time for

the two experiments using the same axis given below.

Lakarkan graf isi padu gas oksigen yang telah dikumpulkan lawan masa

bagi kedua-dua eksperimen dengan menggunakan paksi sama seperti dibawah.


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[2 marks][2 markah]

3 Three experiments were carried out to investigate the factors affecting the rates ofreactions. The following table shows the material used and the time taken to accumulate25 cm3of gas released from each experiment.

Tiga eksperimen telah dijalankan untuk menyiasat faktor-faktor yang mempengaruhi

kadar tindak balas. Jadual di bawahmenunjukkan bahan yang digunakan dan masa

yang diambil untuk mengumpulkan 25 cm3

gas yang dibebaskan dari setiap eksperimen.

(a) Sketch the graphs for the three experiments that show the effervescence of

25.0 cm3of gas on the axes given below.

Lakarkan graf untuk ketiga-tiga eksperimen yang menunjukkanpembuakan 25.0 cm3gas di atas paksi yang telah diberikan di bawah.

Experiment

Eksperimen

Material

Bahan

Time/s

Masa/s

I 25.0 cm3of 0.1 mol dm3 hydrochloric acid +

5.0 g of magnesium ribbon25.0 cm3 asid hidroklorik 0.1 mol dm3 +

5.0 g reben magnesium

40

II 25.0 cm3of 0.1 mol dm3 hydrochloric acid +

5.0 g of magnesium ribbon + 3 drops of

copper(II) sulphate solution25.0 cm3 asid hidroklorik 0.1 mol dm3 + 5.0 g

reben magnesium + 3 titis larutan kuprum(II)

sulfat

30

III 25.0 cm3of 0.1 mol dm3 sulphuric acid +

5.0 g of magnesium ribbon

25.0 cm3 larutan asid sulfurik 0.1 mol dm3 +5.0 g reben magnesium

20


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[3 marks][3 markah]

(b) Why is the time taken to collect 25.0 cm3of gas in Experiment I is longer

than Experiment II?Mengapakah masa yang diambil untuk mengumpulkan 25.0 cm3gas di

Eksperimen I lebih lama berbanding dengan Eksperimen II?

...

[1 mark]

[1 markah]

(c) Based on the collision theory, explain why the time taken to collect 25 cm3

of gas in Experiment III is shorter than in Experiment I.

Berdasasrkan teori perlanggaran, jelaskan mengapa masa yang diambiluntuk mengumpulkan 25 cm3dalam Eksperimen III lebih cepat berbanding

dengan Eksperimen I.

...

...

[2 marks][2 markah]

(d) Calculate the mass of magnesium needed

[1 mol of gas occupies 24 dm 3at room temperature and pressure; Relativeatomic mass: Mg = 24, H = 1, S = 32, O = 16]

Hitungkan jumlah magnesium yang diperlukan

[1 mol gas memenuhi 24 dm 3pada suhu dan tekanan bilik; Jisim atom

relatif: Mg = 24, H = 1, S = 32, O = 16]

(i) to react with hydrochloric acid to produce 2.88 cm3of gas in

Experiment I

untuk bertindak balas dengan asid hidroklorik bagi menghasilkan


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2.88 cm3gas di dalam Eksperimen I.

[2 marks]

[2 markah]

(ii) to react with sulphuric acid to produce 5.86 cm3of gas inExperiment III

untuk bertindak balas dengan asid sulfurik bagi menghasilkan 5.86cm3gas di dalam Eksperimen III.

[2 marks]

[2 markah]

4 The following diagram shows the apparatus set-up of a simple voltaic cell.Gambar rajah berikut menunjukkan radas sebuah sel ringkas.

(a) Identify the following:Kenal pasti yang berikut:

(i) Positive terminal:Terminal positif:

.

(ii) Negative terminal:Terminal negatif:

.

[2 marks]

[2 markah]

(b)

Name the electrolyte used in:

Namakan elektrolit yang digunakan dalam:

(i)

BeakerA:


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Bikar A:

.

(ii) Beaker B:

Bikar B:

.

[2 marks]

[2 markah]

(c) (i) What is the function of the salt bridge?Apakah fungsi titian garam?

.

(ii) Name one solution used as the salt bridge.Namakan satu larutan yang digunakan sebagai titian garam.

.

[2 marks]

[2 markah]

(d) (i) Write a half-equation for the reaction that took place at the positiveterminal.

Tuliskan persamaan setengah bagi tindak balas yang berlaku di

terminal positif.

.

[2 marks]

[2 markah]

(ii) Write an overall equation for the cell reaction.

Tuliskan suatu persamaan keseluruhan bagi tindak balas sel

tersebut.

.

[2 marks]

[2 markah]

(e) Give two differences between the voltaic cell and the electrolytic cell.

Berikan dua perbezaan di antara sel voltan dan sel elektrolisis.


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[2 marks]

[2 markah]

5 An experiment is carried out to investigate the rate of reaction between zinc andhydrochloric acid. The result obtained is as shown in the tablebelow.

Satu eksperimen telah dijalankan untuk menyiasat kadar tindak balas antara zink dan

asid hidroklorik. Keputusan yang diperolehi adalah seperti yang di bawah.

Time/s

Masa/s

Burette reading/cm3

Bacaan buret/cm

Volume of gas/cm3

Isi padu gas/cm

0 50 0

30 64 14.0

60 70 20.0

90 76.5 26.5

120 80 30

150 84 34.0

180 86.5 36.5210 88.5 38.5

240 90.5 40.5

270 92 42

300 93.5 43.5

330 95 45

360 96 46

390 96 46

420 96 46

(a) Plot a graph of the volume of gas released against time on the graph paper

provided below.Plotkan graf isi padu gas yang dibebaskan lawan masa di atas kertas graf

yang telah disediakan di bawah.


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[2 marks][2 markah]

(b) How does the slope of the curve relate to the rate of reaction?

Bagaimanakah cerun graf tersebut boleh dikaitkan dengan kadar tindakbalas?

.. ......

[1 mark]

[1 markah]

(c) Write out the chemical equation for the reaction.Tuliskan persamaan kimia bagi tindak balas tersebut.

.. ......

[1 mark]

[1 markah]

(d) How does the rate of reaction change with time?


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[1 mark]

[1 markah]

6 An experiment is carried out to study the effect of temperature on the rate of reaction betweensodium thiosulphate and 2 mol dm3 hydrochloric acid. The set-up of the apparatus is as shown

in the following diagram.

Satu eksperimen telah dijalankan untuk mengkaji perubahan suhu terhadap kadar tindak

balas di antara natrium tiosulfat dan asid hidroklorik 2 mol dm3. Susunan radas adalahseperti yang ditunjukkan di dalam gambar rajah di bawah.

The time needed for the X to disappear is recorded with the temperature of the sodiumthiosulphate increased. The data obtained is recorded as shown in the following table.

Masa yang diperlukan bagi X untuk hilang dicatatkan bersama-sama dengan peningkatansuhu natrium tiosulfat. Maklumat yang diperolehi dicatatkan seperti yang ditunjukkan dalam

jadual di bawah.

Temperature/oC 28 30 40 50 60 70 80


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Suhu/C

Time taken for X

to disappear/s

Masa yang diambilbagi X untuk

hilang/s

60 53 33 23 17 13 11

/s1

/s1

(a) Plot a graph of the increase in temperature against time on the graph paper

provided below.

Plotkan satu graf peningkatan suhu lawan masa di atas kertas graf yangtelah disediakan.

[2 marks]


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[2 markah]

(b) Based on the result obtained what inference can be made on the rate of

reaction?Berdasarkan keputusan yang diperolehi, apakah inferens yang boleh

dibuat daripada kadar tindak balas?

..

[1 mark]

[1 markah]

(c) What caused the X on the filter paper to disappear?

Apakah yang menyebabkan X hilang daripada kertas turas?

..

[1 mark][1 markah]

(d) Based on the curve obtained, what is the temperature of sodium

thiosulphate when is the rate of reaction is the highest?Berdasarkan graf yang diperolehi, bilakah kadar tindak balas adalah

yang paling tinggi?

..

[1 mark]

[1 markah]

(e) Based on the collision theory, explain how does the temperature affect therate of reaction.

Berdasarkan teori perlanggaran, jelaskan bagaimana suhu mempengaruhi

kadar tindak balas.

..

[2 marks]

[2 markah]

(f)

Fill up the space provided for in table above.

Isikan tempat kosong yang disediakan bagi dalam jadual di atas.

[1 mark][1 markah]


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(g)

What is the relationship between and rate of reaction?

Apakah hubungan di antara dan kadar tindak balas?

..

[1 mark]

[1 markah]

(g)

What is the relationship between and rate of reaction?

Apakah hubungan di antara dan kadar tindak balas?

..

[1 mark][1 markah]

(h) Give an application of temperature on the rate of reaction in our daily life.

Berikan satu aplikasi suhu terhadap kadar tindak balas dalam kehidupan

seharian kita.

[1 mark][1 markah]

7 An experiment is carried to determine the rate of reaction between 50 cm 3 hydrochloric

acid 0.2 mol dm-3and excess calcium carbonate chips. The volume of gas released during

the reaction is recorded every 20 seconds as shown in the table below.Satu eksperimen telah dijalankan untuk menentukan kadar tindak balas antara 50 cm3

asid hidroklorik 0.2 mol dm3 dan serpihan kalsium karbonat yang berlebihan. Isi padu

gas yang berubah ketika tindak balas tersebut dicatatkan setiap 20 saat seperti yangditunjukkan di jadual di bawah.

(b) State one method to verify the gas released?

Nyatakan satu cara untuk mengesahkan gas yang telah dibebaskan?

[1 mark]

[1 markah]

(c) Plot the graph for the volume of gas released against the time taken for thereaction on the graph paper provided.

Plotkan graf isi padu gas yang dibebaskan lawan masa yang diambil bagi


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kadar tindak balas di kertas graf di bawah.

[2 marks]

[2 markah]

(d) Calculate the average rate of reaction for the reaction.Hitungkan purata kadar tindak balas bagi tindak balas tersebut.

[1 mark][1 markah]

(e) If hydrochloric acid is replaced with sulphuric acid, predict the volume of

the gas released.

Jika asid hidroklorik digantikan dengan asid sulfuric, ramalkan isi padugas yang telah dibebaskan.

[1 mark]

[1 markah]

(f) Explain your answer in (e).Jelaskan jawapan anda di (e).


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[1 mark][1 markah]

(g) Sketch on the same axes the curve for the reaction if the calcium carbonate

chips are replaced with calcium carbonate powder.Lakarkan di atas paksi yang sama, graf bagi tindak balas yang berlakujikalau serpihan kalsium karbonat digantikan dengan serbuk kalsium

karbonat.

[1 mark]

[1 markah]

(h) Explain your answer for the difference of the curves plotted in (g) ascompared to (c).

Jelaskan jawapan anda bagi perbezaan antara graf-graf yang telahdiplotkan di (g) dengan (c).


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[2 marks]

[2 markah]

Section B

Bahagian B

[20 marks]

[20 markah]

Answer any one question from this section.

Jawab mana-mana satusoalan daripada bahagian ini.

8 (a) Give the definition for catalyst.

[2 marks]

Berikan takrifan mangkin.[2 markah]

(b) State five characteristics of a catalyst.

[5 marks]

Nyatakan lima ciri-ciri mangkin.

[5 markah]

(c) A group of students carried out two experiments to investigate the factors

affecting the rate of reaction. The table below shows information about the

reactants used in each experiment.

Sekumpulan pelajar menjalankan dua eksperimen bagi menyiasat faktor-

faktor yang mempengaruhi kadar tindak balas.

Experiment

Eksperimen

Reactants

Bahan tindak balas

I 10 cm3 of hydrogen peroxide

10 cm3 hidrogen peroksida

II 10 cm3 of hydrogen peroxide + 2 g of manganese(IV)oxide

10 cm3

hidrogen peroksida + 2 g mangan(IV) oksida


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(i) Based on the information given on the reactants used, sketch two

graphs for the volume of oxygen released against the time on the

same axes.

[4 marks]

Berdasarkan maklumat yang telah diberikan tentang bahan tindak

balas yang digunakan, lakarkan dua graf untuk isi padu oksigenyang dibebaskan kepada masa di atas paksi yang sama.

[4 markah]

(ii) Based on the collision theory, explain the effect of catalyst on the

rate of reaction.

[6 marks]

Berdasarkan teori perlanggaran, jelaskan kesan mangkin terhadap

kadar tindak balas.

[6 markah]

(d) Explain why industry will consider using catalyst even though it will

increase the cost of production.[3 marks]

Jelaskan kenapa industri akan mempertimbangkan untuk menggunakanmangkin walau pun ia akan menaikkan kos pengeluaran.

[3 markah]

9 (a) On a very hot day, the food left on the dining table will turn bad faster thanon a rainy day. Explain why.

[2 marks]

Pada hari yang panas, makanan yang ditinggalkan di atas meja makan

akan basi lebih cepat berbanding dengan hari hujan. Jelaskan kenapa.

[2 markah](b) An experiment is carried out to study the effect of temperature on the rate of reaction

as shown in the diagram below. The sodium thiosulphate is heated and then poured

into the hydrochloric acid and the time taken for the X to disappear is recorded asthe temperature of the sodium thiosulphate used is increased.

Satu eksperimen telah dijalankan untuk mengkaji kesan suhu ke atas kadar tindak

balas seperti yang ditunjukkan di dalam gambar rajah di bawah. Natrium tiosulfattelah dipanaskan dan kemudian dituangkan ke dalam asid hidroklorik, dan masa

yang diambil bagi tanda X untuk hilang sementara suhu natrium tiosulfat yang

digunakan bertambah dicatatkan.


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Based on the experiment, a graph is plotted. Explain how the rate of reaction varies atroom temperature as compared to the increase in the temperature.

Berdasarkan eksperimen, sebuah graf telah diplotkan. Jelaskan bagaimana kadar

tindak balas berbeza pada suhu bilik berbanding dengan apabila ia mengalamipeningkatan suhu.

(i) Calculate the average rate of reaction for the experiment.

[2 marks]

Hitungkan purata kadar tindak balas bagi eksperimen tersebut.

[2 markah](ii) Write out the chemical equation for the reaction.

[2 marks]

Tuliskan persamaan kimia bagi tindak balas tersebut.

[2 markah]

(iii) If 0.1 mol of 20 cm3 of sodium thiosulphate as well as hydrochloric acid is

used in the experiment, calculate the maximum of sulphur formed during

the experiment.[Relative atomic mass: S = 32, Na = 23, O = 16, Cl = 35, H = 1]

[2 marks]

Jika 0.1 mol natrium tiosulfat yang mempunyai isi padu sebanyak 20 cm3

,dan asid hidroklorik digunakan di dalam eksperimen berkenaan,

hitungkan jumlah sulfur yang terbentuk semasa eksperimen tersebut.

[Jisim atom relatif: S = 32, Na = 23, O = 16, Cl = 35, H = 1]

[2 markah]

(iv) Based on the collision theory, explain how the temperature will affect the

rate of reaction.

[6 marks]


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Berdasarkan teori perlanggaran, jelaskan bagimana suhu boleh

mempengaruhi kadar tindak balas.

[6 markah]

(v) If now the manipulated variable is the concentration of the sodium

thiosulphate, how should we alter the original experiment? Explain how

this will affect the rate of reaction.[6 marks]

Jikalau sekarang pemboleh ubah yang dimanipulasikan ialah kepekatan

natrium tiosulfat, bagaimanakah seharusnya kita mengubah eksperimen

yang asal? Jelaskan bagaimana keadaan ini boleh mempengaruhi kadartindak balas.

[6 markah]

Section CBahagian C

[20 marks]

[20 markah]

Answer any one question from this section.

Jawab mana-mana satusoalan daripada bahagian ini.

10 Three experiments were carried out in a laboratory to investigate the factorsaffecting the rate of reaction. The table below shows the formation for the three

experiments.

Tiga eksperimen telah dijalankan di dalam makmal bagi untuk menyiasat faktor-faktor yang mempengaruhi kadar tindak balas. Jadual di bawah menunjukkanpembentukan bagi ketiga-tiga eksperimen tersebut.

Experiment

Eksperimen

Reactants

Bahan tindak balas

I Excess pieces of zinc is added to 100 cm3 of 0.5 mol dm3

hydrochloric acid

Kepingan zink yang berlebihan ditambahkan kepada 100 cm3

asid hidroklorik 0.5 mol dm3

II Excess zinc powder is added to 100 cm3 of 0.5 mol dm3hydrochloric acid

Serbuk zink yang berlebihan ditambahkan kepada 100 cm3 asid

hidroklorik 0.5 mol dm3

III Excess pieces of zinc is added to 100 cm3 of 0.5 mol dm3


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sulphuric acid

Kepingan zink yang berlebihan ditambahkan kepada 100 cm3

asid sulfurik 0.5 mol dm3

(a) Define the rate of reaction and instantaneous rate of reaction.

[4 marks]

Berikan takrifan kadar tindak balas dan kadar tindak balas pada masatertentu.

[4 markah]

(b) In Experiments I and II above, explain why the rate of reaction differs in

the two experiments.

[6 marks]

Dalam Eksperimen I dan II di atas, jelaskan kenapa kadar tindak balas

adalah berbeza antara kedua-dua eksperimen tersebut.

[6 markah]

(c) In Experiment III above, explain how sulphuric acid affects the rate of

reaction as compared to Experiment II.

[6 marks]Dalam Eksperimen III di atas, jelaskan bagaimana asid sulfurikmempengaruhi kadar tindak balasnya berbanding dengan Eksperimen II.

[6 markah]

(d) Give an example in our daily life how we apply the principle of size of

reactants affects the rate of reaction and how we can overcome it.

[4 marks]

Berikan satu contoh dalam kehidupan seharian kita dalam

mengaplikasikan prinsip saiz bahan tindak balas mempengaruhi kadartindak balas dan bagaimana kita mengatasinya.

[4 markah]

11 (a) Define activation energy.

[2 marks]

Berikan takrifan tenaga pengaktifan.


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[2 markah]

(b) With the help of a graph, explain what an energy profile diagram is.

[5 marks]

Dengan bantuan sebuah graf, jelaskan apakah maksud gambar rajah

profil tenaga.

[5 markah]

(c) Based on the collision theory explains the factors needed for a chemicalreaction to occur.

[5 marks]

Berdasarkan teori perlanggaran, jelaskan faktor-faktor yang diperlukan

supaya tindak balas kimia boleh berlaku.

[5 markah]

(d) In the industry of the production of ammonia, explain the criteria needed

for the reaction and how the reaction takes place.

[8 marks]

Di dalam industri pengeluaran ammonia, jelaskan ciri-ciri yangdiperlukan untuk tindak balas tersebut dan bagaimanakah tindak balas

tersebut berlaku.

[8 markah]

Section A

Bahagian A


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1 (a) (i) Cu2+, Fe2+

(ii) Not a carbonate

(b) (i) Could be Fe2+

(ii) Fe2+ present

(c) Light blue precipitate with potassium hexacyanoferrate(II).Or

Dark blue precipitate with potassium hexacyanoferrate(III).

(d) (i) No carbonate present

(ii) Chloride presents

(iii) No sulphate presents

(e) Iron(II) chloride, FeCl2

2 (a) Water displacement method

(b)

(c) 2H2O2(s) 2H2O(l) + O2(g)

(d) Experiment II

(e) The concentration of hydrogen peroxide in experiment II is higher. Therefore,

the rate of reaction will be higher.

(f) To act as a catalyst

(g) The catalyst, manganese(IV) oxide provides an alternative path, which lowers

the activation energy for a reaction, to enable the effective collision between

the particle to take place


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(h)

3 (a)

(b) In Experiment II, the copper(II) sulphate catalyses the reaction by

lowering the activation energy and thus raising the rate of reaction.

(c) In Experiment II, sulphuric acid is a diprotic acid. Since the concentration

of H+ is higher, the frequency of collision will be more and thus effective

collision will be more and raises the rate of reaction. In Experiment I,hydrochloric acid is a monoprotic acid and thus the concentration of H+ is

lower.

(d) (i) Mg + 2HCl MgCl2 + H2

Number of mole of H2 = = 0.12 mol

1.2 mol of H2produce 1.2 mol of Mg

Mg needed = 0 .12 mol 24 = 2.88 g

(ii) Mg + H2SO4 MgSO4 + H2

Number of mole of H2 = = 0.24 mol

0.24 mol of H2produce 0.24 mol of Mg

Mg needed = 0.24 mol 24 = 5.76 g


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4 (a) (i) Copper

(ii) Magnesium

(b) (i) Magnesium nitrate/Magnesium sulphate

(ii) Copper(II) nitrate/Copper(II) sulphate

(c) (i) To complete the circuit by allowing the ions to flow from one half-

cell to the other.

(ii) Diluted sulphuric acid, concentrated potassium chloride

solution/concentrated potassium nitrate solution

(d) (i) Mg(s) Mg2+(aq) + 2e

(ii) Mg(s) + Cu2+(aq) Mg2+(aq) + Cu(s)

(e) Differences between voltaic cell and electrolytic cell

Voltaic cell Electrolytic cellChemical energy Electrical

energy

Electrical energy chemical

energy

Does not use battery Uses battery

Cathode is positive terminal Cathode is negative terminal

Anode is negative terminal Anode is positive terminal

(Any two of the above)

5 (a)


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(b) The slope measures the rate of reaction at an instant.

(c) Zn(s) + HCl(aq) ZnCl2(aq) + H2(g)

(d) As time increases, the rate of reaction decreases.(e) As the time increases, the reactant become lesser and/or has completely

reacted.

(f) The reactants have used up in the reaction.

(g)

= = 0.245 cm3 s1

(h)

= = 0.12 cm3 s1

(i)

= 0.13 cm

3

s

1

6 (a)


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(b) The rate of reaction increases as the temperature increases.

(c) The precipitation of sulphur

(d) When the temperature is at 80 oC

(e) When the temperature increases, the particles in the reactants gain kineticenergy and move faster which increase the collision frequency and

effective collision frequency. Therefore, the rate of reaction increases.

(f)

(g)

measures the rate of reaction

(h) Welding, the higher the temperature, the faster the welding process will

be.

7 (a) HCl(aq) + CaCO3(s) CaCl2(s) + CO2(g) + H2O(l)

(b) The gas produced is passed through lime water. Lime water will turn cloudy.

(c)

(d)

= 0.34 cm3 s1

Time taken for

X to disappear/s

60 53 33 23 17 13 11

/s1

0.017 0.019 0.03 0.043 0.059 0.077 0.09


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(e) 96 cm3

(f) Sulphuric acid is a diprotic acid the 1 mol of the acid contain 2 mol of H+ ion, double

the H+ ion in HCl.

(g)

(h) The curve for (c) use calcium carbonate chips but the curve in (g) uses calcium

carbonate powder. The total exposed area is more in powdered form than in chips

form. Therefore, the rate of reaction will be higher in (g).

Section B

Bahagian B

8 (a) A catalyst is a substance added to the reactants of a reaction, changes the

rate of a reaction. It may change physically but not chemically in the

reaction.

(b) The catalyst is specific in its reaction.

Catalyst can be poisoned and its efficiency is lowered by the presenceof impurities.The catalyst does not change the quantity of the product of reaction

formed.

Only a small quantity of catalyst is needed to affect the rate ofreaction.

Catalyst does not change chemically but can change physically during


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a reaction.

(c) (i)

(ii) A catalyst increases the rate of reaction by providing an

alternative reactive pathway of lower activation energy.When a positive catalyst is used in a reaction, the catalyst

provides an alternative reactive pathway of lower activationenergy as shown in the diagram below.

If the activation energy is lowered, then more of the particlesthat are moving slowly will have collisions.

More particles collide results in a higher frequency of

effective collision.The lower the activation energies that the reaction has toovercome, the higher is the rate of reaction.

(d) In industry, catalyst are widely used in industrial processes to speed up the

rate of reaction to obtain more products in a shorter time. This will reducethe cost of production. The catalyst is needed in a small amount only.

Therefore, the overall cost is still lower.


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9 (a) On a hot day, the temperature of the surrounding is high. The

microorganisms will gain kinetic energy and will collide with the food

particles more often. The effective collision will increase, and thus the rateof reaction will be higher. Therefore, the food will spoil faster on a hot day

as compared to rainy day.

(b) (i)

= 0.98 oC s1

(ii)

Na2S2O3(aq) + 2HCl(aq) 2NaCl(aq) + SO2(aq) + H2O(l) + S(s)

(iii)

2 mol of HCl 1 mol of S, therefore 1 mol of sulphur will yield32 g of sulphur.

(iv)

At higher temperatures, the molecules will gain kinetic

energies to move fasterMore collisions per secondThe frequency of collisions will increase.

Therefore, the effective frequency of collision will also

increaseAt higher temperatures, a greater fraction of the colliding

particles will possess sufficient energy

To overcome the activation energy needed to break the

covalent bonds of reacting moleculesTherefore the rate of reaction will be higher

(v) The fixed variable will be the temperature of the sodium

thiosulphateSo the sodium thiosulphate used will be at room temperature

and no heating is needed. The rate of reaction will be

affectedIncrease in the reactant concentration will increase the

reactant particles in a specific volume of liquid or gas

Molecules must collide with each other in order to react. The

more often they collide, the more chances there is for areaction to take place

As a result, the increases in number of collisions per unit of

time between the reactants particles and hence increases the

effective collision frequencyThe rate of reaction also increases

Section C

Bahagian C


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10 (a) The rate of reaction can be defined as a time measurement of how

fast a chemical reaction occurs.

The rate of reaction at a particular time or at an instance is known

as the instantaneous rate of reaction.

(b) In Experiment I, pieces of zinc is used and in Experiment II, zinc

powder is used.

As the size of particles get bigger such as in pieces, the total

surface exposed for reaction will be less as compared to zinc in

powdery form.

As the size of particles get smaller such as in powdery form, the

total surface area exposed for reaction will be more.

This will increase the number of collisions

Hence, increase the effective frequency collision.

The rate of reaction will be higher in Experiment II than in

Experiment I.

(c) Sulphuric acid is a diprotic acid, while hydrochloric acid is a

monoprotic acid.

For every mole of sulphuric acid used, 2 mol of hydrogen ion is

available for reaction.

Increase in the reactant concentration of hydrogen ion will increase

the reactant particles in a specific volume of liquid or gas.

Therefore, the chances of the particles to collide will be more.

As a result, the increase in number of collisions per unit of time

between the reactant particles.

Hence, the effective collision frequency increases.

The rate of reaction also increases.

(d) When cooking meat, in order to reduce the time of cooking, we

chop the meat into smaller pieces.

Hence the total surface area exposed for cooking or reaction will be

more. The effective frequency collision between the meat particlewith the soup particle will increase.

Therefore, the rate of reaction will be higher and the time of

cooking will be reduced.

11 (a) Activation can be defined as the minimum quantity of energy that must be

available for a collision to be effective in a chemical reaction.

(b) The activation energy can be shown in a diagram called the energy

profile diagram or a reaction profile diagram.


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(Ea is the activation energy barrier that reactants must overcome before a

reaction can take place)

Energy profile diagrams are graph plotted for the energy changes

versus time during chemical reactions.

Before reactants can change into products there is an energy barrier

which reactants must overcome to become products.

The height of this barrier determines the energy at which the

reactants have to gain in order for a chemical reaction to occur and

is called the activation energy.

(c) According to the collision theory, for a chemical reaction to occur the

reactants particles must:

collide with each other

gain enough energy during the collision to overcome activation

energy

the particles must in the proper orientation


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the collision must effective

Only when all the factors mentioned above is fulfilled, that the

chemical reaction between the particles will occur

(d) Ammonia is produced in industry through the Haber process that

harvests ammonia from hydrogen and nitrogen.

Hydrogen and nitrogen at room temperature and pressure do not

react. However, at a higher pressure with corresponding

temperatures, ammonia is released.

The optimum conditions for maximum oxidation of hydrogen and

nitrogen into ammonia in the Haber process is:

oTemperatures between 450550 oC

oPressure between 250 500 atmospheres

oCatalyst: iron powder (Fe)o3 mol of hydrogen gas react with 1 mol of nitrogen gas to

produce 2 mol of ammonia gas.

In the industrial process the temperature is set at 450 oC and

iron powder is used as a catalyst to raise the rate of reaction

In Haber process, the temperature, pressure and catalyst are

used to raise the rate of reaction in order to cut cost and time in the

industry.

The chemical equation for the Haber process:


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ujian penilaian 1 f5 2012

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