25YEARSEndorsed for full syllabus coverageCambridgeChemistrySecond editionPeter CannPeter HughesHODDERDYNAMICEDUCATIONCambridgeInternational AS A LevelChemistrySecond editionPeter Cann and Peter HughesHODDEREDUCATIONAN HACHETTE UK COMPANYAcknowle dge mentsEvery effort has been made totrace all copyright holders,but if amy have been inadvertently overlooked,the Publishers will be pleasedDr.Jeremy Burgess/Science Photo Library;tr Alfred Pasieka/Science Photo Library;p.98t David Hughes/Hemera/Thinkstock;p.98Roscoe/Visuals Unlimited,Inc./Science Photo Library;bl JH Photo/Alamy Stock PhotoKing-Holmes/Science Photo Library;p.580 tl Geoff Tompkinson/Sclence Photo Library:tr James King-Holmes/Science Photo LibraryAlthough every effort has been made to ensure that website addresses are correct at time of going to press,Hodder Education cannot beheld responsible for the content of amy website mentioned in this book.It is sometimes possible to find a relocated web page by typingin the address of the home page for a website in the URL window of your browser.Third-party websites and resources referred to in thispublication have not beenendorsed by Cambridge Assessment International Educat ion.of Cambridge Assessment Inteational Educat ion.Questions froresponsibility for the example answers to quest ions taken from its past question papers which are contained online.Sample answers have been written by the authors.In examinations,the way marks are awarded may be different.References toassessment and/or assessment preparation are the publisher's interpretation of the syllabus requirements and may not fully reflect theof teaching and learning resources in preparing learners for assessment,based on their own professional judgement of their students'answers to questions taken from its past question papers which are contained online.Hachette UK's policy is to use papers that are natural,renewable and recyclable products and made from wood grown in well-managed forests and other controlled sources.The logging and manufacturing processes are expected to conform to the environmentalOrders:please contact Bookpoint Ltd,130 Park Drive,Milton Park,Abingdon,Oxon OX144SE.Telephone:+44(0)1235 827827.Fax:message answering service.You can also order through our website:www.hoddereducation.co.ukISB:9781510480230Peter Cann and Peter Hughes 2020First published in 2015This edition published in 2020 byHodder Education,Carmelite House50Victoria EmbankmentLondon EC4Y ODZImpression number10987654321Year20242023202220212020in amy form or by any means,electronic or mechanical,including photocopying and recording,or held within any information storageFurther details of such licences (for reprographic reproduction)may be obtained from the Copyright Licensing Agency Limited,www.cla.co.ukCover photo School of Chemistry,University of EdinburghIllustrat ions by Barking Dog Art and Aptara IncA catalogue record for this title is available from the British LibraryMIXPaper fromFSCresponslble sourcesFSCC104740