Kbat Kimia SPM

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KBAT KIMIA 2014 1. Inside the onion cells there are some chemical compounds which contain sulfur. When you cut an onion, the cells break and those compounds undergo chemical reaction and they are transformed into a more volatile sulfured compunds, which are released into the air. Di dalam sel-sel bawang terdapat beberapa bahan kimia yang mengandungi sulfur. Apabila anda memotong bawang, sel-sel pecah dan sebatian mengalami tindak balas kimia dan mereka berubah menjadi sebatian sulfur yang terbebas ke dalam udara.

  

The nerve endings in your eyes are very sensitive and so they pick up on this irritation to produce a burning sensation. The brain reacts by telling your tear ducts to produce more water and keep your eyes protected from the irritating acid. One of the trick to make onion-dicing less problematic is to chop the onion under cold water.

Hujung saraf di dalam mata anda sangat sensitif dan mengalami kerengsaan dengan menghasilkan rasa panas. Otak bertindak balas dengan memberitahu saluran air mata untuk menghasilkan lebih banyak air mata dan melindungi mata dari asid ini. Salah satu helah semasa menghiris bawang adalah memotongnya di dalam air sejuk.

(a) Explain the chemical reaction that cause the burning sensation in the eyes. Terangkan tindak balas kimia yang menyebabkan rasa panas di dalam mata.

[1 mark] ………………………………………………………………………………………………………………………….. (b) How the tears reduce the irritating of the eyes?

Bagaimanakah air mata mengurangkan kerengsaan di dalam mata?

[1 mark]

………………………………………………………………………………………………………………………… (c) Explain how chopping onion under cold water can reduce irritating of the eyes. Terangkan bagaimana memotong bawang di dalam air sejuk boleh mengurangkan kerengsaan mata.

[1 mark] ………………………………………………………………………………………………………………………….. (d) Suggest another way to reduce irritating of the eyes. Explain your answer. Cadangkan kaedah lain yang boleh mengurangkan kerengsaan mata. Terangkan jawapan anda.

[2 marks]

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2    2. Diagram shows the release of waste gas containing sulphur dioxide from the smokestack of a power station. This gas can cause one type polution.

Rajah 6.2 menunjukkan pembebasan sisa gas yang mengandungi sulfur dioksida daripada cerobong sebuah stesen kuasa. Gas yang terbebas menyebabkan sejenis pencemaran.

Figure 6.2 / Rajah 6.2 Kassim is a farmer. His farm located near the power station. He found out that his vegetables are not growing healthy. He believe it is because of the soil has been polluted. If you are Kassim, how do you solve this problem. State the problem and the way to overcome. Kassim seorang pekebun. Kebunnya terletak berhampiran dengan stesen kuasa. Dia mendapati sayur-sayurannya tidak membesar dengan sempurna. Dia berpendapat bahawa tanah kebunnya tercemar. Andaikan anda Kassim, bagaimana anda menghadapi masalah ini. Nyatakan masalah dan cara mengatasinya.

_________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ [3 marks] 3. Lim Seng was playing in the playground with his friends. While playing suddenly a bee came and stung his hand. He went to home and told his mother. She apply substance Y that was found in the bathroom on Lim Seng hand. Suggest substance Y that his mother applied on his hand. Explain your answer. 

3    Lim Seng bermain bersama rakan-rakannya di taman permainan. Sedang leka bermain seekor lebah telah menyengat tangannya. Dia mendapatkan ibunya dan memberitahu apa yang berlaku. Ibunya dengan segera menyapukan bahan Y yang diambil dari bilik air. Cadangkan bahan Y yang digunakan oleh ibunya. Jelaskan jawapan anda

_________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ [3 marks] 4.

Shell of the snail is made of compound X. Compound X is an ionic compound which can react with dilute hydrochloric acid. Cengkerang siput dibuat daripada sebatian X. Sebatian X adalah sebatian ionik yang boleh bertindak balass dengan asid hidroklorik cair.

Based   

on the information given, Write a chemical equation for the reaction. State the observation Give a chemical test to identify the gas produced.

Berdasarkan kenyataan yang diberikan, Tuliskan persamaan bagi tindak balas tersebut Nyatakan pemerhatian Berikan satu ujian untuk mengenalpasti gas yang dibebaskan.

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[4 marks]

4    5. Diagram shows a spectacle lenses that made from composite material Z. Rajah menunjukkan kanta cermin mata yang diperbuat daripada bahan komposit Z.

The lenses are clear when indoors or at night and automatically darken when exposed to sunlight. Kanta adalah jelas apabila di dalam rumah atau pada waktu malam dan secara automatik menjadi gelap apabila terdedah kepada cahaya matahari.

What is material Z? Suggest the name of one insoluble salt embedded in the lenses which provide this special property. Explain your answer. Apakah bahan Z? Cadangkan satu nama garam tak larut yang terdapat dalam kanta tersebut yang memberikan ciri istimewa ini. Terangkan jawapan anda.

[3 marks]

_________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ [3 marks] 6. Diagram shows the observation when chicken egg is immersed in solution X. Rajah menunjukkan pemerhatian apabila sebiji telur ayam direndam di dalam larutan X.

5    Suggest solution X which can be easily found in the kitchen and explain the observation. Write a chemical equation to show the reaction. Cadangkan larutan X yang mudah didapati di dapur dan terangkan pemerhatian yang berlaku. Tuliskan persamaan kimia bagi tindak balas yang berlaku.

[4 marks]

_________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ __________________________________________________________________________ 7. Diagram 6 shows two examples of alloys, M and N, which contain copper as the main component. Rajah 6 menunjukkan dua contoh aloi M dan N yang mengandungi kuprum sebagai komponen utama.

Suggest the name of metal added to form alloy M and alloy N. Explain why both alloy is harder than the pure metal. Cadangkan nama logam yang ditambah untuk membentuk aloi M dan aloi N. Terangkan mengapa kedua-dua aloi lebih kuat berbanding logam tulen.

[4 marks]

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6    8. Diagram shows the cross section of an oil rig. Rajah menunjukkan keratan rentas pelantar minyak.

Suggest metal X. Explain the function of metal X. Cadangkan logam X. Terangkan fungsi logam X.

[4 marks]

_________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ 9. Diagram shows a “breathlyzer” which uses by the policemen to detect the presence of alcohol in drunk driver. Rajah menunjukkan alat “breathlyzer” yang digunakan oleh anggota polis untuk mengesan kandungan alkohol bagi pemandu mabuk.

7    Suggest compound Y. Explain how the breathlyzer works? Include a chemical equation in your explanation. Cadangkan sebatian Y. Terangkan bagaimana “breathlyzer” bertindak? Tuliskan persamaan kimia di dalam penerangan anda.

[5 marks]

_________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ __________________________________________________________________ 10. Aminah wants to write a secret message to her friend using invisible ink. She pour some lead(II) nitrate solution into a container. She dips a cotton swab into the solution and starts writing the secret message on a piece of white paper. Then, she lets the ink dry and send the secret message to her friend.

Explain how her friend able to read the secret message clearly using a suitable chemical reaction. Write a chemical equation involved in the reaction. [3 marks]

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8    Peraturan pemarkahan: 1. (a) The sulfured compounds react with the moisture in the eyes forming sulfuric acid. (b) The volatile sulfured compounds will be released but then they react with the cold water, instead of reaching your eyes. (c) The tears diluting the irritating acid during crying. (d) *Freeze the onion before cutting. The cold temperature of the onion will slow down the chemical reaction which forms the volatile sulfured compunds. *Use a super sharp knife. Sharp knife reduce the damage the cell wall of the onion and reduce the production of volatile sulfured componds. * Submerge onions in a bowl of water beforehand. This will draw some of the acidic content into the water so a lot less irritant will be released. 2. Sulphur dioxide gas released from the factory react with rain water to form acid rain which increase the acidity of the soil The farmer should add soda lime/ calcium oxide to the soil The acidity of the soil can be reduced. 3. · Toothpaste · Bee sting is acidic while toothpaste is alkaline · Toothpaste which is alkaline can neutralise the acidity of bee sting

4. · The shell of the snail contain calcium carbonate

Equation: CaCO3 + 2 HCl → CaCl2 + H2O + CO2 · Bubbles produced/ effervesence occur · Deliver the gas released into a test tube containing lime water · Lime water will turn chalky/cloudy/milky

5.· Photochromic glass · Contains silver chloride/ silver bromide/ copper (I) chloride · When expose to light silver chloride will change to silver and the colour darkens. When the intensity of light decreases, silver change to silver chloride again and becomes clear. 6. Solution X is vinegar / ethanoic acid. The shell of chicken egg contains calcium carbonate. Vinegar / ethanoic acid react with calcium carbonate to produce gas bubbles of carbon dioxide. Equation: 2CH3COOH + CaCO3 → (CH3COO)2Ca + CO2 + H2O

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7. Alloy M: Tin Alloy N: Zinc Tin atoms and zinc atoms of different size disrupt the orderly arrangement of pure copper. When force is applied, the layers of copper atoms not easily slide over one another. 8. Metal X is Magnesium (any metal above iron). Steel consists of iron. Magnesium is more electropositive than iron and easily release electron/oxidise to form magnesium ion. Mg → Mg2+ + 2e Magnesium prevent iron from rusting / corrosion.

9. Compound Y is acidified potassium dichromate(VI). The breath of drunk driver contains ethanol. The drunk driver blow his breath into the breathlyzer. The ethanol react with acidified potassium dichromate(VI) and the colour change from orange to green. The reaction produce ethanoic acid and water. C2H5OH + 2[O] → CH3COOH + H2O 10. Pour potassium iodide solution into a bottle spray. Spray the potassium iodide solution on the paper. Potassium iodide solution reacts with lead(II) nitrate to produce yellow precipitate which reveal the secret message. Pb(NO3)2 + 2KI → PbI2 + 2KNO3