[uks] Chemistry 2006(mock) Paper1(e)

2006-F.5 MOCK EXAM-CHEM 1-2

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SECTION A Answer ALL questions in this Section. Write your answers in the spaces provided. Scientists believe that liquid hydrogen could be a substitute for fossil fuel in future. (a)

Give the electronic diagram for a molecule of hydrogen.

(b)

Suggest an industrial method to obtain hydrogen.

(c)

Explain why liquid hydrogen can be used as fuel.

(d)

Nowadays, liquid hydrogen is used as fuel in space shuttles. not gaseous hydrogen, is used.

(e)

Explain why hydrogen is still used to fill weather balloon although it causes explosion easily.

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1.

Explain why liquid hydrogen, but

(5 marks)

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2.

A part of the Periodic Table is shown below. Group Period 2 3 4 5

I

II

III

IV

A C

V

VI

VII

0 B

D

E

F

G I

H

Answer the following questions with the letters given in the above table.

in

Which element has the greatest atomic number?

(b)

Element B can be found as monatomic molecules in nature.

(c)

Which elements, C or H, is more reactive?

(d) in

(i)

Explain.

Explain your answer.

F reacts with I to form compound X. Draw the electronic diagram (showing the electrons in the outermost shell only) of compound X.

(ii) E reacts with I to form compound Y. Draw the electronic diagram (showing the electrons in the outermost shell only) of compound Y.

(iii) Comment on the following statement. “Compound X has a higher melting point than compound Y.”

(8 marks) 2006-F.5 MOCK EXAM-CHEM 1-4

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(a)

3.

6 g of ethanoic acid is dissolved in water to make a 250.0 cm3 solution. (a)

Name the apparatus to make the 250.0 cm3 solution.

(b)

Calculate the concentration (in molarity) of the above solution.

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(c) If a 25 cm3 pipette and another 250 cm3 volumetric flask are given, describe how you can obtain the the diluted solution from the solution in (b).

(5 marks)

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Write equations and expected observations when magnesium is added to (a)

concentrated hydrochloric acid;

(b)

hot concentrated sulphuric acid;

(c)

concentrated nitric acid.

(6 marks) 5.

Write equations only, specifying the reagents and conditions used, to show the conversion of the following reactions. (Hint: At least two reactions are involved in each of the following questions.) (a)

O CH3CH2OH

→

CH3C – OCH2CH3

O O

(b) CH2=CH2

→

HO – C – C – OH

(6 marks) 2006-F.5 MOCK EXAM-CHEM 1-6

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4.

Nylon-6,6 is a polymer which is commonly used for making ropes. hexanedioyl dichloride and hexane-1,6-diammine. O

Nylon-6.6 is synthesised from

O

Cl – C – (CH2)4 – C – Cl

H2N(CH2)6NH2

hexanedioyl dichloride

hexane-1,6-diammine

(a)

State one property of nylon 6,6 which enables it to make ropes.

(b)

(i)

Nylon-6,6 is formed by “condensation polymerization”.

What is meant by this term?

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6.

(ii) Write the repeating unit of nylon-6,6.

(c)

In the plastics industry, the used nylon materials can be recycled. (i)

Suggest a reason for carrying out this process.

(ii) State whether you agree with the following statement or not. “Landfilling is better than pyrolysis for the disposal of nylon waste.” Explain your answer.

(6 marks) 2006-F.5 MOCK EXAM-CHEM 1-7

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7.

Methoxymethane belongs to a homologous series of compounds called ethers. (a). What is meant by the term ‘homologous series’?

(b) Methoxymethane is formed when methanol, bromomethane and sodium react together. The react reaction is shown as follows: 2CH3OH + 2CH3Br + 2Na → 2CH3OCH3 + 2NaBr + X2 (i)

Name X2.

(ii) Methoxymethane burns completely in air to give carbon dioxide and water.

completely

m

Write the chemical equation for the complete combustion of methoxymethane.

(II) Calculate the volume of X2 produced when 30 g of methoxymethane is burnt completely in oxygen.

(iii) Draw the structural formula of another compound which has the same molecular formula of methoxymethane.

(5 marks) 2006-F.5 MOCK EXAM-CHEM 1-8

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(I)

8.

For each of the following experiments, there is ONE mistake in the set-up. State and explain the mistake in each case.

(2 marks) (b)

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(a)

For question 9, candidates are required give a paragraph-length answer. In this question, 6 marks will be awarded for chemical knowledge and 3 marks for effective communication. 9.

A mixture contains iron(III) oxide and copper. Describe how you would conduct an experiment to estimate the percentage by mass of iron in the mixture.

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(9 marks)

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END OF SECTION A

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SECTION B Answer ALL questions in this Section. Write your answers in the spaces provided. 10. The following set-up shows an electrochemical cell:

(a)

What would be observed in beaker X?

(b)

(i)

Write a half equation for the reaction involved.

What would be observed in beaker Y? Write a half equation for the reaction involved.

(ii) Explain why carbon electrode Q is the anode. (c)

What is the direction of current flow in the external circuit?

(d)

Give the function of S.

(e)

Explain why the light bulb becomes dimmer if chlorine gas is passed into the beaker Y. (9 marks)

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When the switch K is closed, an electric current flows through the light bulb.

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11. The following diagram shows the exhausted gases emitted from a bus using diesel oil.

One of these pollutants, X, has a choking smell and can decolourize bromine water. (a)

(i)

Name gas X.

(ii) Write equation to show the reaction between gas X and bromine water. (b)

Explain why carbon monoxide is present in the exhausted gases.

(c) Particulates are also present in the exhausted gases. State ONE environmental problem as associated with the discharge of particulates into the atmosphere. ……………… ……… ………. .

(i)

Name one harmful effect of nitrogen oxides to mankind.

(ii) Suggest how nitrogen oxides are formed inside the bus engine. (iii) (I) e

Suggest one solution to reduce the amount of oxides of nitrogen produced from bus engine.

(II) Give one limitation of your solution proposed in (I). (9 marks)

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(d)

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12. The structural formulae of four common detergents are shown below: Detergent I:

Detergent II:

Detergent III:

(a)

(i)

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Detergent IV:

Which of the above detergent(s) are soapy detergent(s)?

(ii) Explain why soapy detergents cannot be used in hard water. (b)

(i)

Which of the above detergent(s) are biodegradable?

(ii) Biodegradable detergents also cause pollution problems. (c)

(i)

Why?

Explain why a solution of detergent can be used to clean up oil spillages in the sea.

(ii) Name the process described in (i). (9 marks)

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For question 13, candidates are required give a paragraph-length answer. In this question, 6 marks will be awarded for chemical knowledge and 3 marks for effective communication. 13. There are five unlabelled reagent bottles each containing one of the following liquids: potassium chloride, kerosene, zinc nitrate solution, ammonium sulphate solution and water. Suggest how you would carry out tests to distinguish the liquids, using the materials and apparatus listed below. Your answer should include the observation of each test. bunsen burner, test tubes, sodium hydroxide solution and pH paper

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(9 marks)

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END OF PAPER

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