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CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education

CHEMISTRY 0620/02

Paper 2May/June 2003

1 hour Candidates answer on the Question Paper.No Additional Materials required

Centre Number Candidate Number Name

READ THESE INSTRUCTIONS FIRST

Write your name, centre number and candidate number in the spaces provided at the top of this page.Write in dark blue or black pen in the spaces provided on the Question Paper.You may use a pencil for any diagrams, graphs or rough working.Do not use staples, paper clips, highlighters, glue or correction fluid.

Answer all questions.The 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 page 16.

This document consists of 16 printed pages.

SP (SC) S33034/4© CIE 2003 [Turn over

If you have been given a label, look at thedetails. If any details are incorrect ormissing, please fill in your correct detailsin the space given at the top of this page.

Stick your personal label here, ifprovided.

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0620/02 M/J/03

1 The diagram shows part of the Periodic Table.

(a) Answer these questions using only the elements shown in the diagram.

Write down the symbol for an element which

(i) is a transition metal.

(ii) forms an acidic oxide.

(iii) has six electrons in its outer shell.

(iv) has a giant covalent structure.

(v) reacts rapidly with water.

(vi) has a higher proton (atomic) number than iron.

[6]

ForExaminer’s

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LiNa

Fe Cu Zn

C N O F NeHe

S ClBr

ArKrK

I II III IV V VI VII 0

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(b) Some uses of some non-metallic elements are show below.

Draw lines between the boxes to link the elements to their correct uses.

The first one has been done for you.

element use

[4]

(c) The structures of some halogen compounds are shown below.

(i) Describe the type of bonding in compound A.

...................................................................................................................................

(ii) State the simplest formula for compound C.

...................................................................................................................................

(iii) Explain why compound B does not conduct electricity when solid but does conductwhen molten.

...................................................................................................................................

...............................................................................................................................[4]

Cl

Na+

Cl

ClI

A B C

Cl –Na+

Cl –Na+Cl –

Na+Cl –Na+

Br FF

F

F

F

as a lubricanthelium

in balloonscarbon (graphite)

to kill bacteria in waterpurification

chlorine

in oxygen tents inhospitals

argon

in light bulbsoxygen

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0620/02 M/J/03

2 A student investigates the reaction between zinc and hydrochloric acid. The hydrochloric acid is in excess. The student uses the apparatus shown in the diagram.

(a) What should the student do to start the reaction?

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

(b) The student reads the volume of gas in the syringe every minute. The results are shown in the table.

(i) Plot the results on the grid on page 5.

gassyringe

hydrogengas

hydrochloric acidzinc power

small testtube held bya piece ofcotton

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time in minutes 0 1 2 3 4 5 6 7

volume of gas in cm3 0 23 35 45 50 53 55 55

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(ii) Draw the best curve through the points.

(iii) Explain why the volume of gas stays the same after six minutes.

...................................................................................................................................

...............................................................................................................................[5]

(c) The student does the experiment again.The only difference is that the student uses warm, rather than cold, hydrochloric acid. On the grid, draw the shape of the graph you would expect for theexperiment with the warm hydrochloric acid.

[2]

.

0 1

10

20

30

40

50

60

2 3 4 5 6 7

time /min

volu

me

of g

as/c

m3

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0620/02 M/J/03

(d) (i) Balance the equation for the reaction between zinc and hydrochloric acid.

Zn + … HCl → ZnCl2 + H2

(ii) Name the compound which has the formula ZnCl2.

...................................................................................................................................

(iii) Calculate the relative formula mass of ZnCl2.

[3]

(e) Zinc is an element.State the meaning of the term element.

......................................................................................................................................

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

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3 The states of matter are solid, liquid and gas.The diagram below shows how the molecules are arranged in these three states.

(a) State the name given to the change of state labelled

(i) A ...............................................................................................................................

(ii) B ...............................................................................................................................

(iii) C ................................................................................................................................[3]

(b) Which one of the following best describes the movement of molecules in the liquidstate?

Tick one box.

The molecules are not moving from place to place.

The molecules are sliding over each other.

The molecules are moving freely.

[1]

(c) Which of the changes A, B or C, is endothermic?Explain your answer.

..........................................................................................................................................

......................................................................................................................................[2]

B

melting

C

A

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0620/02 M/J/03

(d) Choose from the following list of substances to answer the questions below.

brominechlorine

ironmercury

sodium chloridesulphur

Name a substance which is

(i) a gas at room temperature. ......................................................................................

(ii) a non-metallic liquid at room temperature. ...............................................................

(iii) a compound which is a solid at room temperature. ...................................................[3]

(e) A student set up the apparatus shown in the diagram below.

The white solid is formed because the molecules of hydrogen chloride gas andammonia gas move at random throughout the tube and eventually react with each other.

(i) State the name given to this random movement of molecules.

...................................................................................................................................

(ii) State the name of the white solid formed at X.

...................................................................................................................................

(iii) Suggest why the white solid is formed towards one end of the tube and not in themiddle.

...................................................................................................................................

...............................................................................................................................[3]

(f) What type of chemical reaction takes place when ammonia reacts with hydrochloricacid?

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

X

glass tube

rubber bung

cotton wool soaked inammonia solution

cotton wool soaked inconcentrated hydrochloric acid

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(g) The diagram below shows a simple apparatus that can be used for measuring themelting point of a solid. The liquid in the beaker is heated slowly and the temperature at which the solid B meltsis recorded.

(i) State the name of the piece of apparatus labelled A.

...................................................................................................................................

(ii) Solid B melted at 155oC. Why would water not be a suitable liquid to put in the beaker when using thisapparatus to find the melting point of solid B?

...................................................................................................................................

...................................................................................................................................

(iii) Suggest why the liquid needs to be kept stirred.

...................................................................................................................................

...............................................................................................................................[3]

A

small tube

heat

stirrer

liquid solid B

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4 Catalytic cracking is carried out by oil companies to produce high grade petrol. The process is carried out using an aluminium oxide catalyst. The reaction is a type of thermal decomposition.

(a) Explain the meaning of

(i) thermal decomposition.

...................................................................................................................................

...................................................................................................................................

(ii) catalyst.

...................................................................................................................................

..............................................................................................................................[2]

(b) A typical ‘cracking’ reaction is

C10H22 → C8H18 + C2H4

State the name of the unsaturated compound in this equation.

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

(c) The table shows some of the products obtained by cracking 100g of different ‘fractions’under the same conditions.

(i) Which ‘fraction’ is the best source of fuel for cars?

...................................................................................................................................

(ii) Calculate the amount of paraffin ‘fraction’ needed to make 600g of methane.

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products obtained / g per 100g of ‘fraction’ cracked

‘fraction’cracked hydrogen methane ethene petrol

ethane 10 5 75 2

paraffin 1 15 30 23

diesel 0 6 20 17

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(iii) Complete the equation for the cracking of ethane to produce hydrogen and ethene.

C2H6 → ……………… + ………………[4]

(d) Ethene can be polymerised to form poly(ethene).

(i) Complete the equation below to show the structure of two units in thepoly(ethene) molecule.

(ii) State the name given to this type of polymerisarion.

...............................................................................................................................[2]

5 A precipitate may be formed when two aqueous solutions are mixed. The colour of theseprecipitates may be used to identify particular aqueous ions.

(a) Complete the following table.

[8]

H

H

C

H

H

C

H

H

C

H

H

C+ →

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solution to be added to ion under test test for the ion colour of precipitate

iron(II)

iodide

chloride

sulphate

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(b) When a solution of iron(III) chloride is added to a solution of sodium hydroxide, aprecipitate of iron(III) hydroxide is formed and sodium chloride remains in solution.

Explain how you would obtain a pure dry sample of sodium chloride from this mixture.You may use diagrams to help with your explanation.

[3]

(c) Sodium chloride and iron(III) hydroxide are both compounds.Explain the meaning of the term compound.

..........................................................................................................................................

..................................................................................................................................... [2]

(d) Molten sodium chloride can be electrolysed using graphite electrodes.

Predict the products of this electrolysis

(i) at the anode ..............................................................................................................

(ii) at the cathode ..........................................................................................................[2]

sodium chloride solution

iron(III) hydroxide

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6 This question is about different metals.

The list below shows part of the metal reactivity series .

potassium more reactivemagnesiumaluminiumzincironcopper less reactive

(a) From this list, choose a metal which is extracted using electrolysis.

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

(b) Two thousand years ago, people were able to extract iron and copper from their ores.They were not able to extract aluminium.

Suggest why they were not able to extract aluminium from its ore.

..........................................................................................................................................

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

(c) Uranium is between magnesium and zinc in the reactivity series.

Equal sized strips of magnesium, uranium and zinc were placed in hydrochloric acid.The hydrochloric acid was the same concentration. The results are shown in the table.

(i) Complete the result for uranium and hydrochloric acid.

(ii) Uranium has several isotopes which are radioactive.One of these isotopes is uranium – 235 (235U).

What do you understand by the term isotopes?

...................................................................................................................................

...................................................................................................................................

(iii) State one use of uranium –235.

...............................................................................................................................[3]

ForExaminer’s

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metal observations on adding to hydrochloric acid

magnesium many bubbles of gas produced very rapidly andmagnesium dissolves quickly

uranium

zinc a few bubbles produced at a steady rate and zincdissolves slowly

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0620/02 M/J/03

(d) Metals high in the reactivity series react readily with oxygen.Name the compound formed when magnesium reacts with oxygen.

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

(e) Copper is alloyed with tin to make bronze.

(i) State what is meant by the term alloy.

...................................................................................................................................

...................................................................................................................................

(ii) Suggest why metals are often used in the form of alloys.

...................................................................................................................................

...................................................................................................................................

...............................................................................................................................[2]

(f) Zinc can be extracted by heating zinc oxide with carbon.

ZnO + C → Zn + CO

Explain why carbon is a reducing agent (reductant) in this reaction.

..........................................................................................................................................

..........................................................................................................................................

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

(g) Iron is used as a catalyst in the Haber Process for making ammonia.

3H2 + N2 2NH3

(i) What does the sign mean?

...................................................................................................................................

(ii) What is the approximate percentage of nitrogen in the air?

...............................................................................................................................[2]

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(h) Magnesium is in group II of the Periodic Table.

(i) Draw a diagram to show the electronic structure of magnesium.

(ii) Explain what happens to the magnesium atom when it reacts and forms amagnesium ion.

...............................................................................................................................[3]

ForExaminer’s

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0620/02 M/J/03

Gro

up

DA

TA S

HE

ET

Th

e P

erio

dic

Tab

le o

f th

e E

lem

ents

140

Ce

Cer

ium

58

141

Pr

Pra

seod

ymiu

m

59

144

Nd

Neo

dym

ium

60

Pm

Pro

met

hium

61

150

Sm

Sa

ma

riu

m

62

152

Eu

Eur

opiu

m

63

157

Gd

Gad

olin

ium

64

159

Tb

Terb

ium

65

162

Dy

Dys

pros

ium

66

165

Ho

Hol

miu

m

67

167

Er

Erb

ium

68

169

Tm

Thu

lium

69

173

Yb

Ytte

rbiu

m

70

175

Lu

Lute

tium

71

232

Th

Tho

rium

90

Pa

Pro

tact

iniu

m

91

238 U

Ura

nium

92

Np

Nep

tuni

um

93

Pu

Plu

toni

um

94

Am

Am

eric

ium

95

Cm

Cur

ium

96

Bk

Ber

keliu

m

97

Cf

Cal

iforn

ium

98

Es

Ein

stei

nium

99

Fm

Fer

miu

m

100

Md

Men

dele

vium

101

No

Nob

eliu

m

102

Lr

Law

renc

ium

103

1 HH

ydro

gen

1

7 Li

Lith

ium

3

23 Na

Sod

ium

11

24 Mg

Mag

nesi

um

12

40 Ca

Cal

cium

20

45 Sc

Sca

ndiu

m

21

48 Ti

Tita

nium

22

51 VV

anad

ium

23

52 Cr

Chr

omiu

m

24

55 Mn

Man

gane

se

25

56 Fe

Iron

26

59 Co

Cob

alt

27

59 Ni

Nic

kel

28

64 Cu

Cop

per

29

65 Zn

Zin

c

30

70 Ga

Gal

lium

31

27 Al

Alu

min

ium

13

11 BB

oron

5

12 CC

arbo

n

6

14 NN

itrog

en

7

16 OO

xyge

n

8

19 FF

luor

ine

9

28 Si

Sili

con

14

31 PP

hosp

horu

s

15

32 SS

ulph

ur16

35.5

Cl

Chl

orin

e17

40 Ar

Arg

on18

20 Ne

Neo

n10

4 He

Hel

ium

2

73 Ge

Ger

man

ium

32

75 As

Ars

enic

33

79 Se

Sel

eniu

m

34

80 Br

Bro

min

e

35

84 Kr

Kry

pton

36

39 KP

otas

sium

19

88 Sr

Str

ontiu

m

38

89 YY

ttriu

m

39

91 Zr

Zirc

oniu

m

40

93 Nb

Nio

bium

41

96 Mo

Mol

ybde

num

42

Tc

Tech

netiu

m

43

101

Ru

Rut

heni

um

44

103

Rh

Rho

dium

45

106

Pd

Pal

ladi

um

46

108

Ag

Silv

er

47

112

Cd

Cad

miu

m

48

115

In Indi

um

49

119

Sn

Tin

50

122

Sb

Ant

imon

y

51

128

TeTe

lluriu

m

52

127 I

Iodi

ne

53

131

Xe

Xen

on

54

137

Ba

Bar

ium

56

139

La

Lant

hanu

m

57*

178

Hf

Haf

nium

72

181

TaTa

ntal

um

73

184

WTu

ngst

en

74

186

Re

Rhe

nium

75

190

Os

Osm

ium

76

192 Ir

Irid

ium

77

195

Pt

Pla

tinum

78

197

Au

Gol

d

79

201

Hg

Mer

cury

80

204

Tl

Tha

llium

81

207

Pb

Lead

82

209

Bi

Bis

mut

h

83

Po

Pol

oniu

m

84

At

Ast

atin

e

85

Rn

Rad

on

86

Fr

Fran

cium

87

227

Ac

Act

iniu

m

89

†

9 Be

Ber

ylliu

m

4

III

IIIIV

VV

IV

II0

85 Rb

Rub

idiu

m

37

133

Cs

Cae

sium

55

226

Ra

Rad

ium

88

The

vol

ume

of o

ne m

ole

of a

ny g

as is

24

dm3

at r

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and

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Summary of Examiner’s Notes in IGCSE Chemistry Paper 2 June 2003

Page: 2 Q1 (a) i Any one from Fe, Cu and Zn Q1 (a) ii Most non-metals except hydrogen and noble gases Q1 (a) iii an element in Group VI, O, S Q1 (a) iv Only carbon in table above Q1 (a) v Metals in Group I Li, Na and K Q1 (a) vi Any element in the same period as Fe and to the right of it Cu, Zn, Br, Kr

Page: 3 Q1 (b) (oxygen) oxygen supports respiration Q1 (b) (carbon) because of its layer structure graphite is slippery Q1 (b) (in light bulbs) Argon is inert, it does not react with filament Q1 (b) (in balloons) Helium is less dense than air

Page: 4 Q2 need to answer a Q2 You are told that hydrochloric acid is in excess therefore all the zinc will

react Q2 (b) i All points plotted correctly scores 2 -1 per mistake or omission

Page: 5 Q2 (b) i NB every square = 1 cm³ Q2 (b) ii Smooth curve and through origin (0, 0) Q2 (c) The reaction will go faster but because the amounts of chemicals are the

same it will produce the same final volume of gas. Faster initial rate (steeper slope initially) through (0, 0) ends up at 55cm³

Page: 6 Q2 (d) I x Zn + 2 x Cl + 2 x H atom Need to multiply HCI by 2. Balance hydrogen and chlorine atoms Q2 (d) iii Remember the '2' only multiplies the chloride. Use relative atomic mass 65 Zn i.e. is 65 for zinc. 30

Q2 (e) Other acceptable definitions are: Substance containing only one type of atom. Substance that cannot be broken down to any other substance by

chemical means. This is essential to gain mark. Common mistake - an element is a pure substance, as compounds can be pure, e.g. you can have pure water but it contains two elements

so it is a compound.

Page: 7 Q3 To avoid mistakes label diagram Q3 (a) ii NOT fusion Q3 (b) Do NOT be tempted to tick more than one box. Q3 (b) This refers to solid when the molecules can only vibrate about their

position.

Q3 (b) They are close together but can move past each other - so sliding over each other is a good description.

Q3 (b) This relates to gases where the molecules are far apart and the inter-

molecular forces are very weak

Page: 8 Q3 (d) ii bromine and mercury are both liquids at room temperature but mercury

is a metal Q3 (d) iii in fact it is the only compound; all the others are elements Q3 (e) ammonia molecules have moved further in the same time Q3 (e) Hydrogen chloride molecules move more slowly and travel less distance, so

they meet and react nearer the hydrogen chloride end. Q3 (e) i NOT Brownian motion Q3 (e) ii ammonia chloride is wrong Q3 (e) iii They would only meet in the middle if the molecules moved at the same

speed. Q3 (e) iii The best answer is: ammonia molecules are lighter than hydrogen chloride molecules so

they move/diffuse faster

Page: 9 Q3 (g) ii Must refer to melting point of solid to gain mark. Q3 (g) ii NOT boiling point of water is only 100°C

Page: 10 Q4 (a) ii Idea of increasing rate is essential. NOT alters or changes rate. Q4 (b) Cn H2n + 2 alkane Q4 (b) CnH2n alkene Q4 (c) greatest amount of petrol per 100g Q4 (c) ii Must have units

Page: 11 Q4 (c) iii ethene Q4 (c) iii hydrogen Q4 (d) i Must show continuation Q4 (d) ii Only one product, monomers adds to produce a single product

Page: 12 Q5 (b) NOT decant Q5 (b) NOT just filtrate Q5 (d) i NOT chloride '2' is essential Q5 (d) ii Anode is + electrode, CL¯ attracted, becomes chlorine gas Cathode is - electrode, Na+ attracted, becomes sodium metal

Page: 13 Q6 (a) K is potassium Q6 (b) A specific comment is needed, NOT a general comment - 'they did not

have the right technology' Q6 (c) i any statement that indicates that the reactivity is between magnesium and

aluminium Q6 (c) ii 'Atoms' is essential; not molecules or compounds Q6 (c) ii The best answer is; isotopes are atoms of the same element which have the same proton

number but different nucleon numbers

Page: 14 Q6 (d) a correct formula MgO is acceptable Q6 (e) ii Must be a specific reason. You are advised to select just one reason (only one mark) and do not offer

a list. Q6 (e) ii NOT to improve properties; NOT cheaper; NOT higher melting point Q6 (f) Explanations based on oxidation number and electron transfer would be

acceptable but the above is a simple and clear answer. Q6 (g) ii Answer marked as correct limits 76 → 80%

Page: 15 Q6 (h) i You have to give a diagram as requested in the

question.