Centre NumberCandidateNumber

Candidate Name

International General Certificate of Secondary EducationUNIVERSITYOF CAMBRIDGE LOCAL EXAMINATIONSSYNDICATE

CHEMISTRYPAPER2

MAY/JUNE SESSION 2000

0620/2

1 hour

Candidates answer on the question paper.No additional materials are required.

TIME 1 hour

INSTRUCTIONS TO CANDIDATES

Write your name, Centre number and candidate number in the spaces at the top of this page.

Answer all questions.

Write your answers in the spaces provided on the question paper.

INFORMATION FOR CANDIDATES

The number of marks is given in brackets [ ] at the end of each question or part question.

You may use a calculator.

A copy of the Periodic Table is printed on page 16.

This question paper consists of 15 printed pages and 1 blank page.

SB (SM/JB) OF05702/2@UCLES 2000 [Turn over

FOR EXAMINER'S USE

1

2

3

4

5

6

TOTAL

The diagram shows part of the Periodic Table.

II III IV V VI VII 0

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

(i) Write down the symbol for an element which contains diatomic molecules.

(ii) Write down the symbol for an element which forms a basic oxide.

(iii) Write down the symbol for an element with a smaller proton (atomic)number than lithium, Li.

(iv) Write down the symbol for an element which contains atoms with a fullouter shell of electrons.

DDDD

[4]

(b) Describe three things you would see when a small piece of sodium is added to a beakerof water.

1. .

2. .

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

(c) Lithium (Li), sodium (Na), and potassium (K) are in the same group of the PeriodicTable.The following table compares the properties and electronic structure of these elements.Suggest a value for the boiling point of sodium and complete the rest of the table.

[3]

,.--He

Li C N 0 F Ne

Na Cl Ar

K Br Kr

element boilingpoint reaction with electronic. loC water structure

lithium 1342 steady reaction 2.1

sodium rapid reaction

potassium 760 2.8.8.1

(d) When potassium burns in chlorine, potassium chloride is formed. Part of the structure ofpotassium chloride is shown below.

(i) Describe the type of bonding in potassium chloride.

[1]

(ii) State the simplest formula for potassium chloride.

[1]

(iii) Explain why solid potassium chloride does not conduct electricity.

[1]

(iv) A solution of potassium chloride was acidified with nitric acid.A few drops of silver nitrate solution were then added.

Describe what would be observed.

.

[2]

2 Petroleum is a mixture of many different hydrocarbons.

(a) Which two of the structures A, B, C and D are hydrocarbons?

A

H H

""c=c/

H/ ""H

B

H HI I

H-C-C-Q-H

I IH H

C

H-H

H H H H H H HI I I I I I I

H-C-C-C-C-C-C-C-HI I I I I I IH H H H H H H

D

structure 1 "......................

structure 2 ,..........[1]

(b) The mixture of hydrocarbons in petroleum is separated into different fractions.

(i) What is meant by the term fraction?

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

[1]

(ii) What is the name of the process used to separate these fractions?

[1]

(Hi) During this process, the mixture of hydrocarbons is vaporised and then condensed.Explain what is meant by

vaporised, ................................................................................................................

condensed. [2]

(iv) The separation of the fractions depends on one physical property of thehydrocarbons.

State this property.

.[1]

(c) Octane is a hydrocarbon which can be cracked to produce two different hydrocarbons,hexane and ethene.

CaH1aoctane

~ C6H14

hexane

+ C2H4

ethene

(i) State two conditions which are used to crack octane.

1. .

2. ......[2]

(ii) Which of the three hydrocarbons in the equation above is used to make a polymer?

.[1]

(d) In the diagram below, the boxes on the left give the names of some petroleum fractions.The boxes on the right show some uses of these fractions.Draw lines between the boxes to link the fractions to their correct uses.The first one has been done for you.

lubricating fraction fuel for diesel engines

paraffin fraction fuel for cars

bitumen waxes and polishes

[4]

fraction use

diesel fraction l I aircraft fuels

petrol fraction I " I making roads ]

Zinc is used to galvanise iron. It is also a component of many alloys.

(a) (i) Explain the meaning of the term galvan;se.

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

[1]

(ii) What is the purpose of galvanising iron?

[1]

(iii) Which one of the following, A, B or C, is a correct representation of an alloy?Put a ring around the correct answer.

m ..0)

...... 0)

cD 1m

A B C [1]

(b) Zinc is a metal. State three physical properties that all metals have in common.

1. ...................................................................................................................................

2. ...................................................................................................................................

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

(c) Zinc is extracted from zinc sulphide ore. The ore is first heated in air. The oxygen in theair reacts with the zinc sulphide.

zinc sulphide + oxygen ~ zinc oxide + sulphur dioxide

(i) Which one of the substances in this equation causes acid rain if it escapes into theatmosphere?

[1]

(Ii) Write the formula for a molecule of oxygen.

[1]

(d) 5 tonnes of zinc oxide are needed to produce 4 tonnes of zinc.Calculate the mass of zinc produced from 20 tonnes of zinc oxide.

mass of zinc tonnes [1]

(e) Zinc is extracted by heating the zinc oxide with coke in a blast-furnace. Hot air ispumped through pipes near the bottom of the furnace. Zinc forms as a vapour whichrises to the top of the furnace. The zinc condenses in pans at the top of the furnace.The diagram shows a blast-furnace used for extracting zinc.

Answer the following questions using the letters, A, 8, C or D from the diagram below.

A

8

C

D

(i) Where is the mixture of zinc oxide and coke added to the furnace? DDD

(ii) Where is the air blown in?

(iii) Where does the zinc condense?

[3]

(f) In the blast-furnace, the coke reduces the zinc oxide to zinc. Some of the coke alsoburns to form carbon monoxide.

(i) What is meant by reduction?

[1]

(ii) State the formula for carbon monoxide.

[1]

4 Many buildings are made of concrete. Concrete is a mixture of cement, sand, water andsmall stones.

(a) Explain what is meant by the term mixture.

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

[2]

(b) Sand is largely silicon(IV) oxide. Pure silicon(IV) oxide is a compound. Explain what ismeant by the term compound.

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

[2]

(c) Cement is made by roasting clay with crushed chalk. Chalk is largely calciumcarbonate. When cement is made, some of the calcium carbonate breaks down tocalcium oxide.

CaCO3(s) ~

calcium carbonate

CaO(s)

calcium oxide

+ CO2(g)carbon dioxide

(i) What type of chemical reaction is this?

[1]

eii) Which of the three chemicals in this reaction (calcium carbonate, calcium oxide orcarbon dioxide) has the lowest relative formula mass?

[1]

(d) The diagram shows a concrete beam supporting the roof of a shelter.

concrete beam

"I d.l1L--== -- -'iilik~ ~

Concrete is quite porous. When rainwater soaks through it, some of the calcium oxideslowly dissolves to form aqueous calcium hydroxide. This solution is strongly alkaline.

(i) What is another name for calcium hydroxide?Put a ring around the correct answer.

limestone

quicklime

slaked lime

soda [1]

(ii) Suggest a value for the pH of aqueous calcium hydroxide.

[1]

(iii) How would you use litmus paper to show that aqueous calcium hydroxide isalkaline?

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

.[2]

(e) As aqueous calcium hydroxide drips through the concrete, it reacts with carbon dioxidein the air.

(i) Describe a test for carbon dioxide.

test ...........................................................................................................................

result """"[2]

(ii) The reaction occurring at the surface of the concrete is:

aqueous calcium hydroxide + aqueous carbon dioxide ~ calcium carbonate + water(alkaline) (weakly acidic)

The concrete beam was broken. A few drops of Universal Indicator solution wereadded to the broken surface.

The diagram shows how the pH changes towards the inside of the concrete beam.

inside of the concretepH13

pH9

11mmsurface of the concrete

pH?air

Describe and explain this change in pH.

.

.

[3]

Limonene is a liquid hydrocarbon found in orange peel. It can be extracted by boiling theorange peel with water, using the apparatus shown below. The mixture of limonene andwater distils at a temperature which is 1 °C below the boiling point of water.

heat

D

D

-----limonene

water----------------------

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

[1]

(ii) Suggest what the reading on the thermometer will be when the limonene-watermixture is being distilled.

°C [1]

(iii) Limonene is less dense than water. What information in the diagram shows this?

[1]

(b) The structure of limonene is shown below.

Ctts o:CH2""""C~

I

/C~CH2 CH2

I I

CH2 #CH~C/"

I

CHs

(i) What is the molecular formula of limonene?

[1]

(ii) Some limonene was added to a few drops of aqueous bromine.What colour change would you see in the aqueous bromine?

[2]

(iii) What feature of a limonene molecule is responsible for this colour change?

.[1]

(iv) Name the two substances formed when limonene is burnt in an excess of oxygen.

and .[2]

6 Carbon-14 is a radioactive isotope which is formed in the upper atmosphere.

(a) Explain the meaning of the terms

I(I) radioactive, ...[1]" ... ..., .............

(ii) isotope. , """"""""""""""""""""""""""

.[2]

(b) State one medical use of radioactive isotopes.

... .[1]

(c) Carbon-14 has a nucleon (mass) number of 14.Complete the table below to show the type of charge and number of particles present inone atom of carbon-14.

[6]

type of particletype of charge on the number of particles

particle present

proton

neutron

electron

(d) Carbon-14 slowly changes into atoms of nitrogen. These nitrogen atoms have7 protons, 7 neutrons and 7 electrons.

(i) State the nucleon (mass) number of these nitrogen atoms.

[1]

(ii) Draw a diagram to show the arrangement of the electrons in a nitrogen atom.

[2]

(iii) Name one other element having the same number of valency electrons asnitrogen.

[1]