3na CHEM End-Of-year 09

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Name: __________________________ ( ) Class: Sec 3____

14 October 2009 DURATION: 1 HR 15 MIN

INSTRUCTIONS TO CANDIDATES:

Do not turn over the pages until you are told to do so.

1. Section A consists of 20 Multiple Choice Questions.

Answerall the questions in this section in the OMR Answer Sheet by shading theappropriate oval with a 2B pencil.

2. Section B consists of 4 Structured Questions.

Answerall the questions in the spaces provided in the question paper.

3. Section C consists of 2 Free-Response Questions.

Answerall the questions in the spaces provided.

4. Hand in the OMR Answer Sheet and question paper

separately.

INFORMATION TO CANDIDATES:

1. This paper consists of Sections A, B and C.

2. A copy of the Periodic Table of Elements is attached on page 12 of the Exam

paper.

3. The marks allocated for each question or parts of a question are given in the

brackets [ ].

4. Calculators are allowed.

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REGENT SECONDARY SCHOOL

END-OF-YEAR EXAMINATION 2009

SECONDARY 3 NORMAL (ACADEMIC)

SCIENCE (CHEMISTRY)

FOR EXAMINERS' USE

Section Marks

A / 20

B / 14

C / 16

Total / 50


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______________________________________________________________________

This paper consists of12 printed pages including this cover page.

Section A : Multiple Choice Questions (20 marks)

Choose the correct answers and shade it in the spaces provided on the OMR.

A1 The diagram shows an apparatus set-up used to distil seawater. At which point is

the temperature 1000C?

A2 The diagram below shows part of a measuring cylinder. What is the volume of

liquid in the measuring cylinder?

A 4.2 cm3

B 4.4 cm3

C 4.5 cm3

D 5.0 cm3

A3 What is the purpose of a condenser in a distillation set up?

A To turn liquid into solid

B To turn solid into liquid

C To turn vapour into liquid

D To turn liquid into vapour

A4 Which changes of state occur during distillation?

A Boiling followed by filtration

B Boiling followed by condensation

C Condensation followed by boiling

D Filtration followed by boiling

2

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A5 Which of the following substance will undergo a change of state if it is cooled

from room temperature (25oC) to 0 oC?

Substance Melting point (oC) Boiling point (oC)

A 17 9

B 101 34

C 138 1D 7 58

A6 How many different elements are found in two molecules of nitric acid, HNO3?

A 2

B 3

C 4

D 6

A7 The atomic symbol of sodium is given as Na. How many neutrons are there in an

atom of sodium?

A 11

B 12

C 23

D 34

A8 Which of the following shows the correct charge on each particle in an atom?Electron Proton Neutron

A +1 No charge -1

B -1 +1 +1

C +1 -1 No charge

D -1 +1 No charge

A9 Which group of substances is correctly classified in the correct categories?

Element Mixture Compound

A gold lemon tea water B sand sodium chloride hydrogen gas

C mercury air diamond

D charcoal carbon dioxide milk

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A10 In the diagrams below, each circle represents an atom. Which diagram

represents a compound?

A C

B D

A11 A calcium atom and a calcium ion have the same _____________________.

A size

B number of protons

C number of electrons

D chemical properties

A12 The table below gives the arrangement of electrons in the atoms of four

elements. Which element does not form an ionic compound?

A13 Which two elements will combine to form a covalent compound?

A aluminium and chlorine

B calcium and oxygen

C potassium and sulfur

D carbon and hydrogen

Element Arrangement of

electrons

A

B

C

D

2, 7

2, 3

2, 8, 8

2, 8, 2

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A14 Nitrogen gas reacts with hydrogen gas to produce ammonia gas. The equation

for the reaction is

xN2(g) + yH2(g)zNH3(g)

What are the values ofx, yand z?

x y z

1 3 2

1 2 2

2 2 1

2 1 3

A15 Zinc reacts with steam to form zinc oxide, ZnO according to the equation,

Zn(s) + H2O(g) ZnO(s) + H2(g)

What is the mass of zinc oxide formed from 32.5 g of zinc?

A 40.5 g

B 41.2 g

C 81.0 g

D 146 g

A16 Which word is missing from the following word equation?

acid + base salt + _______

A hydrogen

B oxygen

C water

D nitrogen

A17 Which of the following is a property ofall acids?

A They react with bases

B They are solid at room temperature

C They react with copper to give hydrogen gas

D The pH of their aqueous solutions is greater than 7

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A18 Which set of elements is correctly arranged to show the nature of their oxides?

Acidic Basic AmphotericA Sulphur dioxide Magnesium oxide Aluminium oxide

B Sulphur dioxide Aluminium oxide Magnesium oxide

C Aluminium oxide Copper(II) oxide Aluminium oxide

D Aluminium oxide Copper(II) oxide Magnesium oxide

A19 The table shows the pH value of soil for growing different crops.

Which crop grows best in an alkaline soil?

Crop pHCarrot 5.5 - 7.0

Sugar beet 7.0 - 8.0

Potato 5.0 - 6.5

Oats 4.5 - 6.5

A20 What is not formed when zinc carbonate reacts with dilute hydrochloric acid?

A Carbon dioxide

B ChlorineC Water

D Zinc chloride

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Section B : Structured Questions (14 marks)

Answer the following questions in this section in the spaces provided.

B1 The following shows a list of substances.

From the list, select

(a) a compound: ____________________________________________

(b) two metallic elements: ________________ and ________________

(c) two non-metallic elements: _______________ and ______________

(d) a base: ________________________________________________

[4]

B2 Two white powders, A and B are accidentally mixed. A is soluble in water while

B is insoluble in water. Both chemicals are expensive and therefore it is worth

separating them.

Describe how you would separate the mixture to obtain dry samples of each

chemical. List down clearly the steps you would carry out in the separation

process.

The first step has been done for you.

1. Add water to solids A and B. Stir the mixture._______________________

________________________________________________________________

air carbon neon copper hydrogen

methane oxygensodium

hydroxidewater zinc

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________________________________________________________________

________________________________________________________________

________________________________________________________________

______________________________________________________________ [4]

B3 Sugar has the chemical formula of C6H12O6.

(a) Find the total number of atoms present in one molecule of sugar. [1]

____________________________________________________________

(b) Find the relative molecular mass, Mr, of the sugar molecule. [1]

____________________________________________________________

(c) Sugar burns in oxygen to produce carbon dioxide and water. Fill in the blanksin the equation for the above reaction:

C6H12O6 + 6O2 6________ + 6_________ [2]

B4 Complete the table below to show the number of protons, neutrons and electrons

of the respective ion.

IonNumber of

protonsNumber ofneutrons

Number ofelectrons

Ba2+

I-

[2]

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Section C : Free Response Questions (16 marks)

Answer the following questions in this section in the spaces provided.

C1 (a) The electronic structure of carbon is 2, 4.

Write down the electronic structure of magnesium and oxygen. [1]

(i) magnesium: _______________ (ii) oxygen: ________________

(b) Magnesium oxide, MgO, is an ionic compound whereas methane, CH4, is a

covalent compound. By showing ALL electrons, draw a dot and cross

diagram of each of the compounds below.

(i) Magnesium oxide [3]

(ii) Methane [3]

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(c) Briefly explain why molten ionic compound can conduct electricity.

____________________________________________________________ [1]

C2 Acids react with reactive metals to form gasY and salt.

(a) Name gasY.

___________________________________________________________ [1]

(b) Hydrochloric acid reacts with sodium carbonate to form sodium chloride,

carbon dioxide and water.

Write down the balanced chemical equation for the above reaction.

___________________________________________________________ [1]

(c) List one property of

(i) an acid: __________________________________________________ [1]

(ii) an alkali: _________________________________________________ [1]

(d) Sodium hydroxide, an alkali, neutralises hydrochloric acid according to the

chemical equation below.

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

Write down the ionic equation for the reaction above.

__________________________________________________________ [1]

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(e) The following table shows the different amount of sodium hydroxide (NaOH)

needed to neutralise 25cm3 of each of the acidic fruit juice.

Fruit juiceVolume of sodium hydroxide solution

needed to neutralise the fruit juiceApple 10 cm3

Lime 12 cm3

Lemon 16 cm3

Pineapple 6 cm3

Grapefruit 14 cm3

(i) Which fruit juice is the most acidic? Explain your answer.

________________________________________________________

_______________________________________________________ [2]

(ii) What would be the colour of the Universal Indicator when the juice is

completely neutralised?

_______________________________________________________ [1]

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- End of Paper -

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3na CHEM End-Of-year 09

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