2009 MY 2E Science

Name : _____________________ ( ) Class :_______

MID-YEAR EXAMINATION 2009

SECONDARY 2 EXPRESS

LOWER SECONDARY SCIENCE

Date : 15 May 2009 Day : Friday

Duration : 1 hour 30 minutes Mark : 80 marks

INSTRUCTIONS TO CANDIDATESADDITIONAL MATERIALS

1 OTAS2 Writing papers1 Graph Paper

INSTRUCTIONS TO CANDIDATESWrite your name, class and register number in the spaces provided at the top of this page and on any separate writing paper used.

Section AAnswer all the questions. Shade your answers in the OTAS provided.

Section BAnswer all the questions. Write your answers in the spaces provided.

Section CAnswer all the questions Write your answers in the writing papers provided. Hand in Section C separately

INFORMATION FOR CANDIDATESThe number of marks is given in brackets [ ] at the end of each question or part question.A copy of the Periodic Table is printed on the last page.Approved calculators may be used for this paper.

Name of Setter: Mr Jack TanName of Vetter: Mr Toh Weixiang

__________________________________________________________________________This question paper consists of 15 printed pages, including the cover page.

YISHUN TOWN SECONDARY SCHOOL

Section A (20 marks)Answer all the questions in this section.

1. A compound Y has a melting point of -22ºC and a boiling point of 48 ºC. At which temperature is Y a liquid?

A B C D

-75 -50 -25 0 25 50 75 temperature / oC

2. Which sentence best describes the arrangement of particles in a liquid?

A) They are close together in an orderly arrangement.B) They are close together in a disorderly arrangement.C) They are far apart in an orderly arrangement.D) They are far apart in a disorderly arrangement.

3. How many atoms are there in one molecule of iron (III) nitrate, Fe(NO3)3?

A) 9B) 11C) 13D) 15

4. Which of the following numbers is different for isotopes?

A) Number of protonsB) Number of neutronsC) Number of electrons D) Total number of protons and electrons

5. Which statement about the elements in the Periodic Table is correct?

A) Group 0 elements are unreactive metals.B) Group I elements are reactive non-metals.C) Group VII elements form negative ions.D) The elements become more metallic from left to right across a period.

2

6. The table shows some typical properties of metals and non-metals. Which one of the following set of properties is correct?

Metals Non-metalsA) Good conductor of electricity Usually have a high melting pointB) Usually have a high melting point Good conductor of heatC) Shiny when polished Good conductor of electricityD) Good conductor of electricity Usually dull in appearance

.

7. Which of the following has the most number of electrons?

A) Ca2+

B) S2-

C) NeD) Br-

8. An unknown ion, X2+ contains 23 particles in the nucleus and 10 electrons outside the nucleus. What does the nucleus of the ion X2+ contain?

Protons NeutronsA) 9 14B) 10 13C) 11 12D) 12 11

9. The atom of element X has the electronic configuration 2.8.6. Which statement about element X is correct?

A) X is a poor conductor of electricityB) It forms an ion of charge +2C) It has 2 protons in the outermost shell of an atomD) An atom of X has 12 electrons.

3

10.

Which of the graphs below shows the graph of the number of outer shell electrons against the proton number of the first 12 elements of the Periodic Table?

11.

Which one of the following contains only compounds?

A) Oxygen, water, airB) Nitrogen, neon, chlorineC) Methane, air, sodium chlorideD) Water, carbon dioxide, methane

12.

The diagram below represents the particles in four substances. Which diagram represents a compound?

A B C D

13.

Which of the following statements is true?

A) A mixture of salt and water forms a suspension.B) A solution is a homogeneous mixture where a solute dissolves in a solvent.C) A solution leaves a residue on the filter paper after filtration.D) A saturated solution is one where more solute can be dissolved.

14.

In fizzy drinks, X is the solvent and Y is the solute. Identify X and Y.

X YA) carbon dioxide waterB) water nitrogenC) nitrogen waterD) water Carbon dioxide

4

15.

Methylated spirits will remove permanent ink from some surfaces whereas water will not. The best explanation for this is that

A) methylated spirits is stronger than water.B) permanent ink is soluble in methylated spirits.C) permanent ink is soluble in water.D) water will not evaporate as quickly as methylated spirits.

16.

What is the property that allows us to use fractional distillation to separate ethanol from water in alcoholic drinks?

A) They have different melting points. B) They have different boiling points.C) They have different solubilities.D) They have different colours.

17.

Which of the following is suitable to be obtained by crystallisation?

A) Salt from a mixture of sand and saltB) Water from sugar solutionC) Sugar from sugar solution D) Salt from a mixture of salt and sugar

18.

The graph below shows the solubility of oxygen in the temperature range from 0oC – 60oC.

At room temperature (25ºC), what is the maximum mass of oxygen that can dissolve in 200 grams of water?

A) 0.0018gB) 0.0036gC) 0.0072gD) 0.0144g

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19.

The use of a Liebig condenser in distillation is to ________________.

A) convert a liquid to a solidB) convert a liquid to a vapourC) convert a solid to a liquidD) convert a vapour to a liquid

20.

You are given a sample of crystals. What should you check to test the purity of the crystals?

A) Melting pointB) Shape of crystalsC) Size of crystalsD) Solubility

6

Section B (30 marks)Answer all the questions in this section.

1. Carbon monoxide has a melting point of -205˚C and a boiling point of -192˚C.

(a) In the space below, draw the particles of carbon monoxide at room temperature.

(b) In a student’s notes, he wrote down that air is a mixture of elements.

(i) Define a mixture.

____________________________________________________________________

____________________________________________________________________

(ii) Hence or otherwise, state whether the student is correct. Explain your answer.

____________________________________________________________________

____________________________________________________________________

(iii) Compare a molecule of an element with a molecule of a compound.

____________________________________________________________________

____________________________________________________________________

(c) Water turns into steam at 100ºC.

(i) Name this change in state.

____________________________________________________________________

(ii) Give two differences between the change in state in (i) and evaporation.

____________________________________________________________________

____________________________________________________________________

[1]

[1]

[2]

[2]

[1]

[2]

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2. (a) Complete the following table.

ElementNucleon Number Protons Neutrons Electrons

Mg 24

64 29 28

Fe3+ 56

Br - 80

31 15 18

(b) In the boxes below, draw the full electronic structure of an atom and ion of nitrogen.

.

(c)

Write down the electronic configuration of the atom and ion of nitrogen.

Atom: _____________________ Ion: _________________________

[5]

[4]

[2]

8

Atom Ion

3. The figure below shows a chromatogram obtained by separating the food colouring used in a new type of isotonic drink.

(a) Why does the black spot move further than the white spot?

____________________________________________________________________

(b) Give one precaution when obtaining this chromatogram.

____________________________________________________________________

(b) Calculate the Rf value of the black spot.

(c) Is the colouring pure? Explain your answer.

____________________________________________________________________

____________________________________________________________________

(d) Why should the starting line be drawn in pencil and not ink?

____________________________________________________________________

____________________________________________________________________

(e) Give one advantage of using chromatography to analyse food samples.

____________________________________________________________________

____________________________________________________________________

[1]

[1]

[1]

[1]

[1]

[1]

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4. The diagram below shows the apparatus used to obtain water from sea water.

(a) What is the name of this process?

____________________________________________________________________

(b) What is the purpose of the boiling chips?

____________________________________________________________________

____________________________________________________________________

(c) How do you know the water collected is pure?

____________________________________________________________________

____________________________________________________________________

(d) Label the water in and water out for the condenser.

X: _________________________ Y: ________________________

[1]

[1]

[1]

[1]

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Y

X

Section C (30 marks)

Draw the graph in question 1 on the graph paper provided. Answer all the questions in this section on the writing paper provided. Begin each question on a fresh piece of writing paper.

1. (a) Kate wants to find out the amount of a solute that can dissolve in different volumes of

solvents. The given solvent is water and the solute is sugar. For different amounts of

water, she added sugar till no more sugar can dissolve, and then recorded the mass of

the sugar.

The table below shows the results of her investigation.

Volume of water/ cm3 10 20 30 40 50 60Mass of sugar dissolved/ g 14 32 43 61 76 91

(i) Using the data from the table, plot a graph of mass of sugar dissolved against

volume of water. [4]

(ii) Find the gradient of the graph. [1]

(iii) From the graph, how much sugar can be dissolved in 35 cm3 of water? [1]

(b) Describe, with labelled diagrams, how you would obtain a pure, dry sample of

copper (II) sulphate crystals from a solution of copper (II) sulphate solution. [4]

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2. (a) The graph below shows how the solubility of 4 different substances, vary with

temperature. The solubility of a substance refers to the maximum amount of solute

dissolved in a fixed amount of solvent. In this experiment, all substances were dissolved

in 100 cm3 of water.

(i) Describe the trend between solubility and temperature for the substance P. [1]

(ii) At which temperature does P and R have the same solubility? [1]

(b) At 10ºC, it takes a long time for the different solutes to dissolve.

(i) Describe an experiment to determine how stirring would affect the speed of dissolving. Include in your description the independent variable, the dependent variable and two factors to be kept constant. [4]

(ii) Suggest two other ways beside stirring that result in the solutes dissolving faster. [2]

(c) List two characteristics of a heterogeneous solution. [2]

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3. (a) You are given a mixture containing the following liquids:

Liquid Boiling Point / ˚C

Methanol 64

Ethanol 78

Propanol 98

Butanol 118

(i) Name the most suitable method that can be used to separate the above liquid

mixture into its components. [1]

(ii) Draw a labeled diagram showing how the apparatus can be set up for the method

named in (i). [5]

(iii) Which liquid would be obtained first? Explain your answer. [2]

(b) An unknown substance is a liquid at room temperature but quickly solidified in a

refrigerator. Describe two ways to determine if the liquid is a pure substance. [2]

~ End of Paper ~

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DATA SHEETThe Periodic Table of the Elements

Group

I II III IV V VI VII 0

1

HHydrogen

1

4

HeHelium

2

7

LiLithium

3

9

BeBeryllium

4

11

BBoron

5

12

CCarbon

6

14

NNitrogen

7

16

OOxygen

8

19

FFluorine

9

20

NeNeon

10

23

NaSodium

11

24

MgMagnesium

12

27

AlAluminium

13

28

SiSilicon

14

31

PPhosphorus

15

32

SSulphur

16

35.5

ClChlorine

17

40

ArArgon

18

39

KPotassium

19

40

CaCalcium

20

45

ScScandium

21

48

TiTitanium

22

51

VVanadium

23

52

CrChromium

24

55

MnManganese25

56

FeIron

26

59

CoCobalt

27

59

NiNickel

28

64

CuCopper

29

65

ZnZinc

30

70

GaGallium

31

73

GeGermanium

32

75

AsArsenic

33

79

SeSelenium

34

80

BrBromine

35

84

KrKrypton

36

85

RbRubidium

37

88

SrStrontium

38

89

YYttrium

39

91

ZrZirconium

40

93

NbNiobium

41

96

MoMolybdenum

42

TcTechnetium

43

101

RuRuthenium

44

103

RhRhodium

45

106

PdPalladium

46

108

AgSilver

47

112

CdCadmium

48

115

InIndium

49

119

SnTin

50

122

SbAntimony

51

128

TeTellurium

52

127

IIodine

53

131

XeXenon

54

133

CsCaesium

55

137

BaBarium

56

139

LaLanthanum

57 *

178

HfHafnium

72

181

TaTantalum

73

184

WTungsten

74

186

ReRhenium

75

190

OsOsmium

76

192

IrIridium

77

195

PtPlatinum

78

197

AuGold

79

201

HgMercury

80

204

TlThallium

81

207

PbLead

82

209

BiBismuth

83

PoPolonium

84

AtAstatine

85

RnRadon

86

FrFrancium

87

226

RaRadium

88

227

AcActinium

89

*58-71 Lanthanoid series90-103 Actinoid Series

a = relative atomic massKey x = atomic symbol b = proton (atomic) number

140

CeCerium

58

141

PrPraseodymium59

144

NdNeodymium

60

PmPromethium

60

150

SmSamarium

62

152

EuEuropium

63

157

GdGadolinium

64

159

TbTerbium

65

162

DyDysprosium

66

165

HoHolmium

67

167

ErErbium

68

169

TmThulium

69

173

YbYtterbium

70

175

LuLutetium

71

232

ThThorium

90

PaProtactinium

91

238

UUranium

92

NpNeptunium

93

PuPlutonium

94

AmAmericium

95

CmCurium

96

BkBerkelium

97

CfCalifornium

98

EsEinsteinium

99

FmFermium

100

MdMendelevium

101

NoNobelium

102

LrLawrencium

103

The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.)

a

X

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