Level 2 Chemistry (90308) 2010 - MACscience · Level 2 Chemistry, 2010 90308 Describe the nature of structure and bonding in different substances Credits: Four 9.30 am Monday 22 November

Level 2 Chemistry, 201090308 Describe the nature of structure and bonding

in different substances

Credits: Four9.30 am Monday 22 November 2010

Check that the National Student Number (NSN) on your admission slip is the same as the number at the top of this page.

You should answer ALL the questions in this booklet.

A periodic table is provided on the Resource Sheet L2–CHEMR.

If you need more space for any answer, use the page(s) provided at the back of this booklet and clearly number the question.

Check that this booklet has pages 2–10 in the correct order and that none of these pages is blank.

YOU MUST HAND THIS BOOKLET TO THE SUPERVISOR AT THE END OF THE EXAMINATION.

For Assessor’s use only Achievement Criteria

Achievement Achievement with Merit

Achievement with Excellence

Describe the bonding in simple molecules and the nature of types of solids.

Link selected properties of simple molecules and different types of solids to their structure.

Discuss properties of substances in terms of structure and bonding.

Overall Level of Performance

903080

9 0 3 0 82

For Supervisor’s use only

© New Zealand Qualifications Authority, 2010All rights reserved. No part of this publication may be reproduced by any means without the prior permission of the New Zealand Qualifications Authority.

You are advised to spend 45 minutes answering the questions in this booklet.

QUESTION ONE

(a) DrawtheLewisstructure(electrondotdiagram)foreachofthefollowingmolecules.

Molecule Lewis structure

O2

SO2

SiCl4

(b) Lewisstructuresforthreemoleculesaregivenbelow.

Completethetablebygivingthenameoftheshapeofeachmolecule.

Molecule Lewis structure Name of shape

CH2Cl2 Cl C ClH

H

NCl3Cl N Cl

Cl

BF3B

FF

F

2

Chemistry 90308, 2010

Assessor’suse only

(c) ThefollowingtableshowstheLewisstructureandtheshapeofthemoleculesforNOClandH2S.

NOCl H2S

Lewis structure O N Cl H S H

Name of shape bent bent

Theshapeofbothmoleculescanbedescribedasbent.However,thesemoleculesdonothavethesamebondangle.

Discusswhythesemoleculeshavedifferentbondangles.

Youranswermustinclude:

• factorswhichdeterminetheshapeofeachmolecule

• theapproximatebondangleforeachmolecule.

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QUESTION TWO

(a) Twoburettesaresetup.Oneburettecontainswater(apolarliquid)andtheothercontainscyclohexane(anon-polarliquid).Theliquidisallowedtorunfromeachburetteinasteadystream.Achargedplasticruleristhenplacednearthestreamofeachliquid.

Charged ruler

CyclohexaneWater

+ + + + + + + + +

(i) Describewhatwillbeseenwhenthechargedrulerisplacednearthestreamofeachliquid.

(ii) Explaintheseobservations.

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(b) TheLewisstructuresofthreemoleculesareshownbelow. (i) Foreachmolecule,circlethecorrectanswertoshowwhetherthemoleculeispolaror

non-polar.

CH3ClCl

HH C H polar non-polar

CCl4 Cl C ClCl

Cl

polar non-polar

NH3H N H

H polar non-polar

(ii) Discussthefactorswhichdeterminewhetheramoleculeispolarornon-polar.

Youmustusethethreemoleculesfrom(b)(i)aboveasexamplesinyouranswer.

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QUESTION THREE

(a) Statethetypeofparticles(atoms/ions/molecules)presentinthetwosolidsMgCl2andSiO2.

Solid Magnesium chlorideMgCl2

Silicon dioxideSiO2

Particles (atoms / ions / molecules)

(b) Thefollowingtableshowssomephysicalpropertiesofthesetwosolids.

Solid MgCl2 SiO2

Melting point / °C 712 1700Solubility in water soluble insoluble

Compareandcontrastthesephysicalproperties(meltingpointandsolubilityinwater)ofthesetwosolids.

Youranswermustinclude:

• referencetothetypeofsolid

• thetypeofparticle

• theattractiveforcesbetweentheparticles,foreachofthetwosolids.

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QUESTION FOUR

Thediagramsbelowshowthestructureofametallicsolid.

SuzanneBonifaceetal,NCEA Level 2 Chemistry(Auckland:ESAPublications,2008),p102.

(a) Nametheparticlesinthediagramsabove.

Particle Name of particle

A

B

(b) Copperisagoodconductorofelectricityandisductile.Itisoftenusedtomakeelectricalwires.

Usethediagramsabovetodiscusshowthestructureofcopperallowsittobemadeintoelectricalwires.

Inyouransweryoushould:

• Describetheparticlesincopperandtheattractiveforcesbetweentheparticles.

• Relateitsstructuretobothpropertiesoutlinedabove.

For copyright reasons, this resource cannot be

reproduced here.

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Question number

Extra paper for continuation of answers if required.Clearly number the question.

90

30

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Level 2 Chemistry (90308) 2010 - MACscience · Level 2 Chemistry, 2010 90308 Describe the nature of structure and bonding in different substances Credits: Four 9.30 am Monday 22 November