Preview Chemistry HL, 2nd Edition by Catrin Brown, Mike Ford (2014)

H IG H E R L E V E L

P E A R SO N B ACC A L AU R E AT E

HIGHER LE VEL

Chemistry

2nd Edition

CATRIN BROWN • MIKE FORD

Supporting every learner across the IB continuum


Published by Pearson Education Limited, Edinburgh Gate, Harlow,
Essex, CM20 2JE.
www.pearsonglobalschools.com
Text © Pearson Education Limited 2014
Edited by Tim Jackson
Proofread by Eilidh McGregor
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Typeset by Phoenix Photosetting, Chatham, Kent
Original illustrations © Pearson Education 2014
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The rights of Catrin Brown and Mike Ford to be identified as authors of
this work have been asserted by them in accordance with the Copyright,
Designs and Patents Act 1988.
First published 2014

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British Library Cataloguing in Publication Data
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ISBN 978 1 447 95975 5
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Acknowledgements
We would like to thank David Moore for his invaluable help with and
feedback on this title.
The authors wish to thank Professor Colin Oloman, of the University of
British Columbia, Canada for his valuable input and professional advice
on the text.
We are grateful also to the following IB senior educators who provided
useful feedback on the manuscript: Dr. Garth Irwin, Dr. Karen Mclean
and Oksana Jajecznyk.
The authors and publisher would like to thank the R. Bruce Weisman
laboratory at Rice University for permission to use their fullerene
ozonide kinetics data and Dr. Julian Davies at University of British

Columbia for permission to use his data on beta lactamase enzymes.
The author and publisher would like to thank the following individuals
and organisations for permission to reproduce photographs:
(Key: b-bottom; c-centre; l-left; r-right; t-top)
Alamy Images: Clive Sawyer 254bl, Pictorial Press 59r, Shawn Hempel
- Food 746bc; Catrin Brown: 11bl, 163tr, 177bc, 180tl, 358bc, 383c,
420tl; Corbis: David Lees 808br, Michael DeYoung / Design Pics 851bl,
NASA 849b, Ted Levine 460c; DK Images: Clive Streeter 285t; Eva
Campbell: 161b, 171br, 473bc, 476t, 477cr, 483t, 486tc, 503br; Fotolia.
com: Aaron Amat 42b, Africa Studio 140br, alessandrozocc 489tr,
Andrej Kaprinay 942bc, bilderstoeckchen 214b, Can Balcioglu 216tl,
cosma 446cr, goodluz 216tr, GoodMood Photo 11cr, jarerd 254br,
joris484 837tr, Jürgen Fälchle 327cr, Kzenon 965bc, nikesidoroff 528c,
Nikolai Sorokin 210c, photolife95 301tr, PixelThat 332cl, quayside 270c,
sas 221bl, spotmatikphoto 255bl, supakitmod 31br, Unclesam 935t;

ii

Glow Images: 769bc, Adam Gault 889tr; Jupiterimages: photos.com
255br; Pearson Education Ltd: Trevor Clifford 961c, Sozaijiten 960c;
Phillipa Hudson: 748t; Science Photo Library Ltd: A.dex,publiphoto
Diffusion 884Bl, 59Bc, 100Cr, 130Bl, 211Cr, 215T, 249Cr, 326Bl, 478Br,
489Tl, 600Tl, 876Bl, 886Cl, 906Bl, 919Tr, 933Bc, 945Tr, Adam HartDavis 407Bc, 845C, Adrian Thomas 375Tr, Adrienne Hart-Davis 129T,
250Cl, 621Br, Aj Photo / Hop Americain 447Bl, Alexis Rosenfeld 817Cr,
Andrew Lambert Photography 10Cl, 18B, 21Br, 23Br, 39Bc, 48B, 49Cr,
74Tl, 87Bc, 100Tc, 112Tr, 113C, 114Cl, 114Br, 115T, 117C, 121C, 125T,
132C, 132Bl, 142Tl, 142Tc, 187C, 248Bl, 248Br, 283C, 312Tl, 322Tl,
354Tl, 358Cl, 358Cr, 365Cr, 369Cr, 391Cl, 417Tr, 419Tr, 426Cl, 428Bc,
476Tc, 477Tl, 478Tl, 486Bl, 488Tl, 492Cl, 492Br, 493B, 502Tc, 504Cl,
509Tr, 531Cr, 637Cr, 708Tl, 873Tr, 917Br, 943Cr, Argonne National

Laboratory 607Tr, 608C, Astier - Chru Lille 913Br, Astrid & HannsFrieder Michler 580C, 597Cr, 621C, Biophoto Associates 728Tc, 753Br,
Bjorn Svensson 827Tr, Bob Edwards 930Bl, Brian Bell 683Bc, Bsip
Vem 712Cl, Carlos Dominguez 455Bc, Carol And Mike Werner 799C,
Charles Angelo 379B, Charles D. Winters 2C, 5Br, 16C, 39Tr, 96C, 112Cl,
114Tr, 123T, 313Tr, 324Tl, 338Cl, 347Br, 352Tl, 353Tr, 380Bl, 385Br,
407Tr, 418Tc, 448Bc, 451C, 491Tr, 655Cr, Chemical Design 742Tc,
Chemical Design Ltd 645Bc, Chemical Design Ltd., Oxford 617Br,
Chris Knapton 529C, Clive Freeman / Biosym Technologies 778Tl, Clive
Freeman, The Royal Institution 203T, 479Bc, 606Tl, 691Cr, Cnri 911Cr,
Cordelia Molloy 116Tl, 219Tl, 397Tr, 716Bl, 751Br, 946Br, Cristina
Pedrazzini 532C, D. Phillips 310C, D. Phillips / The Population Council
711B, D. Vo Trung / Eurelios 697Br, David A. Hardy 70B, David Hay
Jones 237Tr, David Mccarthy 606Br, David Nunuk 902Bl, David Parker
646Tc, David Scharf 172Tc, David Taylor 69Br, 629C, Dennis Flaherty
904Cl, Dept. Of Physics, Imperial College 71B, Digital Instruments /
Veeco 628Tc, Dirk Wiersma 134Bl, 591Br, Dr David Wexler, Coloured
By Dr Jeremy Burgess 944Tl, Dr Juerg Alean 794Tl, Dr Mark J. Winter
662T, 685Tc, Dr P. Marazzi 890Tl, 915Br, Dr Tim Evans 126Tl, 128Tl,
164Cl, 688Tl, 756C, Du Cane Medical Imaging Ltd 912Bc, Edward
Kinsman 37Cr, 656Cl, Efda-Jet 796Cl, Emilio Segre Visual Archives
642Bc, Equinox Graphics 898Bl, 940Bl, Eye Of Science 172Bc, 411Tl,
461Br, Franz Himpsel / University Of Wisconsin 626Bc, Friedrich
Saurer 943C, 943Cl, Geoff Kidd 740Bl, Geoff Tompkinson 560Tl, 860Tc,
George Bernard 12R, Gustoimages 391Tr, Hank Morgan 62Tc, Hazen
Group, Lawrence Berkley National Laboratory 760Bl, Heine Schneebeli
415Br, Hewlett-Packard Laboratories 629Tr, Hybrid Medical Animation
713T, 735Bc, J-L Charmet 431Bc, James Bell 610Tl, James King-Holmes
634Br, 654Bl, 931Br, James King-Holmes / Ocms 651Bc, James Prince
531C, Jean-Claude Revy, Ism 593Br, Jean-Loup Charmet 945Tl, Jeremy
Walker 766C, 776B, Jerry Mason 69Tr, 69Cr, 133Br, 800C, Jim Dowdalls

870Bl, Jim Edds 8Bc, Jim Varney 925Br, John Bavosi 880Bl, 885Cr, John
Mclean 484Tl, John Mead 770Tc, Juergen Berger 861C, Kenneth Eward
/ Biografx 75Tr, 166T, 188T, 231Tr, 631Cr, Kevin Curtis 944Br, Laguna
Design 57Bl, 146Tc, 629Bc, 896Bc, 899Cr, Lawrence Berkeley National
Laboratory 115B, 155Bc, 271C, Lawrence Lawry 168Br, Lawrence
Livermore National Laboratory 586Cl, Leonard Lessin 521Bc, M.h.
Sharp 611Cr, Manfred Kage 597Br, Mark Thomas 422Bl, Martin Bond
399C, Martin Shields 371Bc, Martyn F. Chillmaid 6Tl, 12L, 13Br, 48Tl,
112Tl, 112Tc, 184Bl, 245Tr, 278Tl, 284Cl, 301Br, 363Tr, 394Bc, 404C,
596Tl, 619C, 948Bl, Massimo Brega, The Lighthouse 713B, Mauro
Fermariello 925Tr, 946Tr, Maximilian Stock Ltd 442C, Mehau Kulyk
529B, Mere Words 811Cl, Michael Donne 864Tl, Michael Szoenyi
353Cr, Mikkel Juul Jensen 840Bl, N K D Miller 879Br, Nasa 197C,
768Tl, Natural History Museum, London 670C, Nypl / Science Source
4Cl, Oulette & Theroux, Publiphoto Diffusion 914Tl, Pasieka 100Cl,
127Br, 139Br, 170Tr, 178Tl, 218Bl, 405Br, 582Tl, 586Tl, 672Tc, 732Bl,
872T, Patrick Landmann 587Bl, 756Tl, 797Cr, 803T, 811Tr, 813T, Paul
J. Fusco 941Cr, Paul Rapson 466Bc, 677Br, 760Tc, 778Bl, Peggy Greb
/ Us Department Of Agriculture 657Bc, 948Br, Phantatomix 745Tr,
Philippe Benoist / Look At Sciences 904Br, Philippe Plailly 56C, Philippe
Psaila 146Bc, 346Tl, Photostock-Israel 761Br, Physics Dept.,imperial


College 58B, Physics Today Collection / American Institute Of Physics
626Cl, Pierre Philippon / Look At Sciences 431Cr, Power And Syred
695Bl, Prof. K Seddon & J. Van Den Berg / Queen’s University, 371Tr,
Prof. K.seddon & Dr. T.evans, Queen’s University Belfast 517Tl, 517Tr,
Laguna Design 903Tr, Ramon Andrade 3Dciencia 895Tr, 902C, Ray
Ellis 775C, Ria Novosti 65Cr, 97Cr, 594Bc, 783Cr, 805C, Rich Treptow
182T, Robert Brook 634Tl, 635Bc, 738Tl, Russell Kightley 149Cr, 201Br,

202Tl, 630Cl, 861Br, 893Bc, 895C, Saturn Stills 705T, Scientifica, Visuals
Unlimited 592C, Scott Camazine 887Br, Sheila Terry 4Br, 452Tc, 599Tr,
746Tl, Simon Fraser 329Tr, 344C, 397Br, 634Cl, 772Tl, Simon Fraser
/ Mauna Loa Observatory 824Br, Sinclair Stammers 687Br, St Mary’s
Hospital Medical School 876Tc, St. Bartholomew’s Hospital 869Tr,
Steve Gschmeissner 680Tr, Steve Horrell 614Bl, Susumu Nishinaga
138C, 143Tr, 168Bl, 877Br, Tek Image 549Br, Tom Mchugh 636Cl, Tony
Craddock 637Br, Us Department Of Energy 294T, 797T, 804Tl, 933T, Us
Dept. Of Energy 932Cl, Victor De Schwanberg 455Tc,Victor Habbick
Visions 171tl, Vincent Moncorge / Look at Sciences 439tc, Volker Steger
92c, 842tc, Wladimir Bulgar 703b; Shutterstock.com: ggw1962 28bl,
Susan Santa Maria 46b
Cover images: Front: Alamy Images: Olga Khoroshunova
All other images © Pearson Education
We are grateful to the following for permission to reproduce copyright
material:
Figures
Figure on page 170 from p2 of />prizes/physics/laureates/2010/popular-physicsprize2010.pdf © Airi
Iliste/The Royal Swedish Academy of Sciences, © The Royal Swedish
Academy of Sciences 2010; Figure on page 280 adapted from http://
www.vernier.com/products/sensors/spectrometers/svis-pl/, with kind
permission from Vernier Software & Technology; Figure on page 761
adapted from Fluorescent Guest Molecules Report Ordered Inner
Phase of Host Capsules in Solution Author(s): Dalgarno, S. J. DOI:
10.1126/SCIENCE.1116579 Date: Sep 23, 2005 Volume: 309 Issue: 5743,
reprinted with permission from AAAS; Figure on page 761 adapted

from />improvedmethod_moyer.shtml; Figure on page 882 adapted from
β-lactamase enzymes identified during the age of antibiotics, Professor Karen
Bush with permission; Figure on page 548 adapted from University of

California Museum of Paleontology’s Understanding Science (http://
www.understandingscience.org)., />imagedetail.php?id=130&topic_id=&keywords=, Copyright 2006 by
The University of California Museum of Paleontology, Berkeley, and the
Regents of the University of California.
Text
Quote on page 973 from Richard Feynman The Physics Teacher Vol. 7,
issue 6, 1969, pp. 313–320, reproduced with permission from American
Association of Physics Teachers (c)1969; Extract on page 981 from
Physics and Philosophy: The Revolution in Modern Science ISBN-13: 9780141182155 Penguin Modern Classics (Werner Heisenberg) p.25, with
kind permission from Penguin Books Ltd.
Every effort has been made to contact copyright holders of material
reproduced in this book. In some instances we have been unable to
trace the owners of copyright material, and we would appreciate any
information that would enable us to do so. Any omissions will be
rectified in subsequent printings if notice is given to the publishers.
The Understandings, Applications and Skills, Guidance, Essential
ideas, past exam questions, corresponding mark schemes provided
on the eBook, assessment criteria and prescribed essay titles have
been reproduced from IB documents and past examination papers.
Our thanks go to the International Baccalaureate for permission to
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iii


Contents
Introduction

vii

01 Stoichiometric relationships
1.1

Introduction to the particulate nature of matter and chemical
change

3

1.2

The mole concept

14

1.3

Reacting masses and volumes

28

02 Atomic structure
2.1

The nuclear atom

58

2.2

Electron configuration

69

12.1 Electrons in atoms

85

03 Periodicity
3.1

The Periodic Table

3.2

Periodic trends

98
102

13.1 First-row d-block elements

119

13.2 Coloured complexes

130

04 Chemical bonding and structure
4.1

Ionic bonding and structure

140

4.2

Covalent bonding

148

4.3

Covalent structures

155

4.4

Intermolecular forces

173

4.5

Metallic bonding

181

14.1 Further aspects of covalent bonding and structure

185

14.2 Hybridization

199

05 Energetics and thermochemistry
5.1

Measuring energy changes

211

5.2

Hess’s law

225

5.3

Bond enthalpies

230

15.1 Energy cycles

237

15.2 Entropy and spontaneity

247

06 Chemical kinetics
6.1

iv

Collision theory and rates of reaction

272

16.1 Rate expression and reaction mechanism

286

16.2 Activation energy

300


07 Equilibrium

7.1

Equilibrium

17.1 The equilibrium law

311
330

08 Acids and bases
8.1

Theories of acids and bases

346

8.2

Properties of acids and bases

350

8.3

The pH scale

355

8.4

Strong and weak acids and bases

360

18.1 Lewis acids and bases

363

18.2 Calculations involving acids and bases

366

18.3 pH curves

378

8.5

393

Acid deposition

09 Redox processes
9.1

Oxidation and reduction

9.2 & 19.1

Electrochemical cells

406
425

10 Organic chemistry
10.1 Fundamentals of organic chemistry

464

10.2 Functional group chemistry

482

20.1 Types of organic reactions

496

20.2 Synthetic routes

512

20.3 Stereoisomerism

514

11 Measurement and data processing and analysis
11.1 Uncertainties and errors in measurement and results

530

11.2 Graphical techniques

540

11.3 Spectroscopic identification of organic compounds

548

21.1 Spectroscopic identification of organic compounds

566

12 Option A: Materials
A.1 Materials science introduction

582

A.2 Metals and inductively coupled plasma (ICP) spectroscopy 589
A.3 Catalysts

603

A.4 Liquid crystals

609

A.5 Polymers

616

A.6 Nanotechnology

626

A.7 Environmental impact: plastics

633

A.8 Superconducting metals and X-ray crystallography

639

A.9 Condensation polymers

653

A.10 Environmental impact: heavy metals

659

v


Contents

13 Option B: Biochemistry
B.1 Introduction to biochemistry

672

B.2 & B.7

679

Proteins and enzymes

B.3 Lipids

710

B.4 Carbohydrates

721

B.5 Vitamins

725

B.8 Nucleic acids

729

B.9 Pigments

739

B.10 Stereochemistry in biomolecules

749

B.6 Biochemistry and the environment

755

14 Option C: Energy
C.1

Energy sources

768

C.2

Fossil fuels

773

C.3 & C.7

Nuclear fusion and fission

787

C.4

Solar energy

814

C.5

Environmental impact: global warming

823

C.6

Electrochemistry, rechargeable batteries, and fuel cells

829

C.8

Pholtovoltaic and dye-sensitized solar cells (DSSC)

844

15 Option D: Medicinal chemistry

vi

D.1 Pharmaceutical products and drug action

860

D.2 Aspirin and penicillin

870

D.3 Opiates

879

D.4 pH regulation of the stomach

885

D.5 Antiviral medications

892

D.7 Taxol: a chiral auxiliary case study

900

D.8 Nuclear medicine

905

D.9 Drug detection and analysis

916

D.6 Environmental impact of some medications

930

Green chemistry
Experimental work in chemistry
Internal assessment

Theory of knowledge
Advice on the extended essay
Strategies for success
Index

940
942
945
950
961
968
972


Introduction
Authors’ introduction to the second edition
Welcome to your study of IB Higher Level chemistry.
This book is the second edition of the market-leading
Pearson Baccalaureate HL chemistry book, first
published in 2009. It has been completely rewritten
to match the specifications of the new IB chemistry
curriculum, and gives thorough coverage of the
entire course content. While there is much new
and updated material, we have kept and refined the
features that made the first edition so successful. Our

personal experience and intimate knowledge of the
entire IB chemistry experience, through teaching and
examining, curriculum review, moderating internal
assessment and leading workshops for teachers

in different continents, has given us a unique
understanding of your needs in this course. We
are delighted to share our enthusiasm for learning
chemistry in the IB programme with you!

Content
The book covers the three parts of the IB syllabus:
the core, the AHL (additional higher level) material
and the options, of which you will study one. Each
chapter in the book corresponds to a topic or option
in the IB guide, in the same sequence. The core and
AHL material for a topic are combined in the same

chapter, so that you can see the full development of
each concept. The sequence of sub-topics within
each chapter is given in the contents page.
Each chapter starts with a list of the Essential ideas
from the IB chemistry guide, which summarize the
focus of each sub-topic.

Essential ideas
3.1 The arrangement of elements in the Periodic Table helps to predict
their electron configuration.

This is followed by an introduction, which gives
the context of the topic and how it relates to your
previous knowledge. The relevant sections from the
IB chemistry guide for each sub-topic are then given

as boxes showing Understanding, and Applications

and skills, with notes for Guidance shown in italics
where they help interpret the syllabus.

Understandings:
●

Atoms contain a positively charged dense nucleus composed of protons and neutrons (nucleons).
Guidance
Relative masses and charges of the sub-atomic particles should be known, actual values are given in section 4 of the
IB data booklet. The mass of the electron can be considered negligible.

Applications and skills:
●

Use of the nuclear symbol notation A
Z X to deduce the number of protons, neutrons, and electrons in atoms
and ions.

The text covers the course content using plain
language, with all scientific terms explained and
shown in bold as they are first introduced. It follows
IUPAC nomenclature and definitions throughout.

We have been careful also to apply the same
terminology you will see in IB examinations in all
worked examples and questions.

vii

Introduction

The nature of science
Throughout the course you are encouraged to think
about the nature of scientific knowledge and the
scientific process as it applies to chemistry. Examples
are given of the evolution of chemical theories as
new information is gained, the use of models to
conceptualize our understanding, and the ways in
which experimental work is enhanced by modern
technologies. Ethical considerations, environmental
impacts, the importance of objectivity, and the

responsibilities regarding scientists’ code of
conduct are also considered here. The emphasis is
not on learning any of these examples, but rather
appreciating the broader conceptual themes in
context. We have included at least one example in
each sub-section, and hope you will come up with
your own as you keep these ideas at the surface of
your learning.

Key to information boxes
A popular feature of the book is the different
coloured boxes interspersed through each chapter.

Nature of
science
This is an overarching theme in the
course to promote concept-based

learning. Through the book you
should recognize some similar themes
emerging across different topics. We
hope they help you to develop your
own skills in scientific literacy.

These are used to enhance your learning as explained
using examples below.
NATURE OF SCIENCE

The story of Fleming’s discovery of penicillin is often described as
serendipitous – a fortunate discovery made by chance or by accident.
But it was more than that. Would not the majority of people who
noticed the plates were contaminated simply have thrown them away,
likely disappointed at the ‘failed experiment’? The difference was that
Fleming had the insight to observe the plates carefully and ask the right
questions about why a clear ring appeared around the fungal growth.
Scientists are trained to be observant and to seek explanations for what
they see, and this must include the unexpected. As Louis Pasteur once
famously said, ‘Chance favours only the prepared mind’. Consider to
what extent scientific discoveries are only possible to scientists who are
trained in the principles of observation and interpretation.

The disposal of plastics is a major global problem. The very features
that make plastics so useful, such as their impermeability to
water and low reactivity, mean they are often non-biodegradable
and so remain in landfill sites for indefinite periods of time. It
is estimated that about 10% of plastics produced end up in the
ocean, causing widespread hazards to marine life. Measures to try
to address this problem include developments of more efficient

recycling processes, biodegradable plastics, and plastic-feeding
microorganisms. A reduction in the quantities of plastic produced
and used is also urgently needed – which is something for which
every individual can share responsibility.

Utilization
Applications of the topic through
everyday examples are described here,
as well as brief descriptions of related
chemical industries. This helps you to
see the relevance and context of what
you are learning.

viii

Internationalmindedness
The impact of the study of
chemistry is global, and includes
environmental, political and socioeconomic considerations. Examples
of this are given to help you to see
the importance of chemistry in an
international context.

Freeze-drying is an effective process for the preservation of food
and some pharmaceuticals. It differs from standard methods of
dehydration in that it does not use heat to evaporate water, but
instead depends on the sublimation of ice. The substance to be
preserved is first frozen, and then warmed gently at very low pressure
which causes the ice to change directly to water vapour. The process
is slow but has the significant advantage that the composition of the

material, and so its flavour, are largely conserved. The freeze-dried
product is stored in a moisture-free package that excludes oxygen,
and can be reconstituted by the addition of water.


The person who researched and patented tetraethyl lead as a
petroleum additive was the same person who later was responsible
for the discovery and marketing of chlorofluorocarbons (CFCs) as
refrigerants. Thomas Midgley of Ohio, USA, did not live to know
the full extent that the long-term impact his findings would have on
the Earth’s atmosphere. He died in 1944, aged 55, from accidental
strangulation after becoming entangled in ropes and pulleys he had
devised to get himself in and out of bed following loss of use of his
legs caused by polio. Perhaps his epitaph should have been ‘The
solution becomes the problem’.

Interesting fact
These give background information
that will add to your wider knowledge
of the topic and make links with other
topics and subjects. Aspects such as
historic notes on the life of scientists
and origins of names are included
here.

Laboratory work
Experiment to determine the empirical formula of MgO

These indicate links to ideas for
lab work and experiments that

will support your learning in the
course, and help you prepare for the
Internal Assessment. Some specific
experimental work is compulsory, and
further details of this are in the eBook.

Hess’s law is a natural
consequence of the law of
conservation of energy. If you
know the law of conservation
of energy, do you automatically
know Hess’s law?

Full details of how to carry out this experiment with a worksheet are
available online.
A sample of magnesium is heated and the change in mass
recorded. From this, the ratio of moles of magnesium to oxygen can
be determined.

TOK
These stimulate thought and consideration of knowledge issues
as they arise in context. Each box contains open questions to help
trigger critical thinking and discussion.

Key fact
These key facts are drawn out of the main text and highlighted in
bold. This will help you to identify the core learning points within
each section. They also act as a quick summary for review.

In writing the ionization reactions

of weak acids and bases, it is
essential to use the equilibrium
sign.

The concentrations of H+ and
OH− are inversely proportional
in an aqueous solution.

Examination hint
These give hints on how to approach questions, and suggest
approaches that examiners like to see. They also identify common
pitfalls in understanding, and omissions made in answering questions.

Challenge yourself
These boxes contain open questions that encourage you to think about
the topic in more depth, or to make detailed connections with other
topics. They are designed to be challenging and to make you think.

CHALLENGE
YOURSELF
6 Explain why oxygen behaves as a
free radical despite having an even
number of electrons.

ix


Introduction

eBook

In the eBook you will find the following:
Interactive glossary of scientific
words used in the course
● Answers and worked solutions to all
exercises in the book

Worksheets
Interactive quizzes
● Animations
● Videos

●

●
●

For more details about your eBook, see the following section.

Questions
There are three types of question in this book:

1. Worked example with Solution
These appear at intervals in the text and are used to
illustrate the concepts covered.

They are followed by the solution, which shows the
thinking and the steps used in solving the problem.

Worked example
Calomel is a compound once used in the treatment of syphilis. It has the empirical

formula HgCl and a molar mass of 472.08 g mol–1. What is its molecular formula?
Solution
First calculate the mass of the empirical formula:
mass(HgCl) = 200.59 + 35.45 = 236.04 g mol–1
(236.04) × x = M = 472.08
∴x=2
molecular formula = Hg2Cl2

2. Exercises
These questions are found throughout the text. They
allow you to apply your knowledge and test your
understanding of what you have just been reading.

The answers to these are given on the eBook at the
end of each chapter.

Exercises
64 Calculate the mass of potassium hydroxide, KOH, required to prepare 250 cm3 of a 0.200 mol dm–3
solution.

x


3. Practice questions
These questions are found at the end of each chapter.
They are mostly taken from previous years’ IB
examination papers. The mark-schemes used by

examiners when marking these questions are given
in the eBook, at the end of each chapter.

Practice questions
1 How many oxygen atoms are in 0.100 mol of CuSO4.5H2O?
A 5.42 × 1022

B 6.02 × 1022

C 2.41 × 1023

D 5.42 × 1023

Answers and worked solutions
Full worked solutions to all exercises and practice questions can be found in the ebook, as well as regular
answers.
Hotlink boxes can be found at the end of each chapter, indicating that there are weblinks available
for further study. To access these links go to www.pearsonhotlinks.com and enter the ISBN or title
of this book. Here you can find links to animations, simulations, movie clips and related background
material, which can help to deepen your interest and understanding of the topic.
We truly hope that this book and the accompanying online resources help you to enjoy this fascinating subject
of IB Higher Level chemistry. We wish you success in your studies.
Catrin Brown and Mike Ford

xi


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05
It takes considerably more
heat energy to increase
the temperature of a
swimming pool by 5 °C
than boil a kettle of water
from room temperature.
The swimming pool
contains more water
molecules and so has a
larger heat capacity.
The water in the kettle has
a higher temperature but
the water in the swimming
pool has more heat energy.
Temperature is a measure of
the average kinetic energy of
the molecules.

Video

Create notes

This relationship allows the heat change in a material to be calculated from the
temperature change.

When considering the relationship between different objects the heat capacity is
often a more convenient property. The heat capacity (C) is defined as the heat needed
to increase the temperature of an object by 1 K.

heat change (q )
temperature change (DT )

A swimming pool has a larger heat capacity than a kettle.
A temperature rise of 1 K is
the same as a temperature
rise of 1 °C.

Worksheets
Select the icon to view a
worksheet with further
activities

• The specific heat capacity (c) is defined as the heat needed to increase the
temperature of unit mass of material by 1 K.
heat change (q)
mass (m) ì temperature change (T)
ã The heat capacity (C) is defined as the heat needed to increase the
temperature of an object by 1 K.
specific heat capacity (c) =

heat capacity (C) =

Our shared knowledge
is passed on from one
generation to the next by
language. The language we
use today is often based
on the shared knowledge
of the past which can

sometimes be incorrect.
What do such phrases as
“keep the heat in and the
cold out” tell us about
previous concepts of heat
and cold? How does the
use of language hinder the
pursuit of knowledge?

heat change (q)
temperature change (∆T)

NATURE OF SCIENCE
Although heat is a concept that is familiar to us all – we need it to cook our food and to keep
us warm – it is a subject that has proved to be difficult for science to understand. We are
equipped by our sense of touch to distinguish between high and low temperature but heat has
proved challenging on a more fundamental level. The development of different temperature
scales was an important technological and scientific step as it recognized the need for
objectivity in scientific measurement, and the need to calibrate the instruments to one or more
one fixed points. However, scientific understanding in this area was still confused at the time.
The original Celsius scale, for example, had the boiling point of water at a lower temperature
than its melting point, so it was not clear what it was quantifying and other scales used arbitrary
fixed points such as the melting points of butter, or the temperatures of the Paris wine cellars.
The observation that heat can be added to melting ice or boiling water without changing its
temperature was a significant observation in the distinction between the heat and temperature.
Our modern distinction is based on our particulate theory of matter. Temperature is a measure
of the individual particle’s kinetic energy and heat, a process by which energy is transferred.

PRIVATE NOTE
Do exercises 1–6, and worksheet for

homework.

Note

216

xii

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Energetics/thermochemistry

heat capacity (C) =

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Solution
heat change = m × c × ∆T
= 10.0 g × 0.385 J g–1 °C–1 × –60.0 °C (the value is negative as
the Cu has lost heat)
= –231 J

Exercises
1

When a sample of NH4SCN is mixed with solid Ba(OH)2.8H2O in a glass beaker, the mixture changes
to a liquid and the temperature drops sufficiently to freeze the beaker to the table. Which statement is
true about the reaction?
A
B
C
D

2

Which one of the following statements is true of all exothermic reactions?
A
B
C
D

3

The process is endothermic and ∆H is –
The process is endothermic and ∆H is +

The process is exothermic and ∆H is –
The process is exothermic and ∆H is +
They produce gases.
They give out heat.
They occur quickly.
They involve combustion.

If 500 J of heat is added to 100.0 g samples of each of the substances below, which will have the
largest temperature increase?
Substance

Specific heat capacity / J g–1 K–1

A

gold

0.129

B

silver

0.237

C

copper

0.385

D

water

4.18

4

The temperature of a 5.0 g sample of copper increases from 27 °C to 29 °C. Calculate how much heat
has been added to the system. (Specific heat capacity of Cu = 0.385 J g–1 K–1)

5

Consider the specific heat capacity of the following metals.

A

0.770 J

B

1.50 J

Metal

Specific heat capacity / J g–1 K–1

Al

0.897

Be

1.82

Cd

0.231

Cr

0.449

C

3.00 J

D

A

Al

B

Be

Select the icon to take an
interactive quiz to test

your knowledge

3.85 J

Worked solutions

1 kg samples of the metals at room temperature are heated by the same electrical heater for 10 min.
Identify the metal which has the highest final temperature.
6

Quiz

C

Cd

D

Cr

The specific heat of metallic mercury is 0.138 J g–1 °C–1. If 100.0 J of heat is added to a 100.0 g sample
of mercury at 25.0 °C, what is the final temperature of the mercury?

CHALLENGE
YOURSELF
2 Suggest an explanation for
the pattern in specific heat
capacities of the metals in
Exercise 3.

Select the icon at the
end of the chapter to
view worked solutions to
exercises in this chapter

Enthalpy changes and the direction of change

Answers

There is a natural direction for change. When we slip on a ladder, we go down, not up.
The direction of change is in the direction of lower stored energy. In a similar way, we
expect methane to burn when we strike a match and form carbon dioxide and water.
The chemicals are changing in a way which reduces their enthalpy (Figure 5.5).

Select the icon at the end
of the chapter to view
answers to exercises in
this chapter

217

xiii


01

Stoichiometric relationships


Essential ideas

1.1

Physical and chemical properties depend on the ways in which
different atoms combine.

1.2

The mole makes it possible to correlate the number of particles with
a mass that can be measured.

1.3

Mole ratios in chemical equations can be used to calculate reacting
ratios by mass and gas volume.

The birth of chemistry as a physical science can be traced back to the first successful
attempts to quantify chemical change. Carefully devised experiments led to data that
revealed one simple truth. Chemical change involves interactions between particles that have
fixed mass. Even before knowledge was gained of the atomic nature of these particles
and of the factors that determine their interactions, this discovery became the guiding
principle for modern chemistry. We begin our study with a brief introduction to this
particulate nature of matter, and go on to investigate some of the ways in which it can
be quantified.

The reaction between ignited
powdered aluminium and iron
oxide, known as the thermite
reaction:
2Al(s) + Fe2O3(s) → Al2O3(s) +
2Fe(s)

Significant heat is released by the
reaction, and it is used in welding
processes including underwater
welding. The stoichiometry of the
reaction, as shown in the balanced
equation, enables chemists to
determine the reacting masses
of reactants and products for
optimum use.

The term stoichiometry is derived from two Greek words – stoicheion for element and
metron for measure. Stoichiometry describes the relationships between the amounts
of reactants and products during chemical reactions. As it is known that matter is
conserved during chemical change, stoichiometry is a form of book-keeping at the
atomic level. It enables chemists to determine what amounts of substances they should
react together and enables them to predict how much product will be obtained. The
application of stoichiometry closes the gap between what is happening on the atomic
scale and what can be measured.
In many ways this chapter can be considered as a toolkit for the mathematical content
in much of the course. It covers the universal language of chemistry, chemical
equations, and introduces the mole as the unit of amount. Applications include
measurements of mass, volume, and concentration.
You may choose not to work through all of this at the start of the course, but to come
back to these concepts after you have gained knowledge of some of the fundamental
properties of chemical matter in Chapters 2, 3, and 4.

1.1

Introduction to the particulate
nature of matter and chemical

change

Understandings:
●

Atoms of different elements combine in fixed ratios to form compounds, which have different
properties from their component elements.
Guidance
Names and symbols of the elements are in the IB data booklet in Section 5.

Mixtures contain more than one element and/or compound that are not chemically bonded
together and so retain their individual properties.
● Mixtures are either homogeneous or heterogeneous.
●

3


01

Stoichiometric relationships
Applications and skills:
●

Deduction of chemical equations when reactants and products are specified.
Guidance
Balancing of equations should include a variety of types of reactions.

●
●

Application of the state symbols (s), (l), (g), and (aq) in equations.
Explanation of observable changes in physical properties and temperature during changes of state.
Guidance
● Names of the changes of state – melting, freezing, vaporization (evaporation and boiling),
condensation, sublimation and deposition – should be covered.
● The term ‘latent heat’ is not required.

Antoine-Laurent Lavoisier (1743–1794) is often called the ‘father of chemistry’. His
many accomplishments include the naming of oxygen and hydrogen, the early
development of the metric system, and a standardization of chemical nomenclature.
Most importantly, he established an understanding of combustion as a process
involving combination with oxygen from the air, and recognized that matter retains its
mass through chemical change, leading to the law of conservation of mass. In addition,
he compiled the first extensive list of elements in his book Elements of Chemistry (1789).
In short, he changed chemistry from a qualitative to a quantitative science. But, as
an unpopular tax collector in France during the French Revolution and Terror, he was
tried for treason and guillotined in 1794. One and a half years after his death he was
exonerated, and his early demise was recognized as a major loss to France.

Chemical elements are the fundamental building blocks
of chemistry

Antoine-Laurent Lavoisier,
French chemist (1743–1794).

A chemical element is a
single pure substance,
made of only one type
of atom.

Pictographic symbols used
at the beginning of the 18th
century to represent chemical
elements and compounds.
They are similar to those
of the ancient alchemists.
As more elements were
discovered during the 18th
century, attempts to devise a
chemical nomenclature led
to the modern alphabetic
notational system. This
system was devised by the
Swedish chemist Berzelius and
introduced in 1814.

4

The English language is based on an alphabet of just 26 letters. But, as we know,
combining these in different ways leads to an almost infinite number of words, and
then sentences, paragraphs, books, and so on. It is similar to the situation in chemistry,
where the ‘letters’ are the single substances known as chemical elements. There are


only about 100 of these, but because of the ways in which they combine with each
other, they make up the almost countless number of different chemical substances in
our world.
In Chapter 2 we will learn about atomic structure, and how each element is made up of
a particular type of atom. The atoms of an element are all the same as each other (with

the exception of isotopes, which we will also discuss in Chapter 2), and are different
from those of other elements. It is this distinct nature of its atoms that gives each
element its individual properties. A useful definition of an atom is that it is the smallest
particle of an element to show the characteristic properties of that element.
To help communication in chemistry, each element is denoted by a chemical symbol
of either one upper case letter, or one upper case letter followed by a lower case letter.
A few examples are given below.
Name of element

Symbol

carbon

C

fluorine

F

potassium

K

calcium

Ca

mercury

Hg

tungsten

W

You will notice that often the letter or letters used are derived from the English name of
the element, but in some cases they derive from other languages. For example, Hg for
mercury comes from Latin, whereas W for tungsten has its origin in European dialects.
Happily, these symbols are all accepted and used internationally, so they do not need to
be translated. A complete list of the names of the elements and their symbols is given
in Section 5 of the IB data booklet.

Chemical compounds
are formed from more
than one element
Some elements, such as nitrogen
and gold, are found in native
form, that is uncombined with
other elements in nature. But
more commonly, elements
exist in chemical combinations
with other elements, in
substances known as chemical
compounds. Compounds contain
a fixed proportion of elements,
and are held together by chemical
bonds (discussed in Chapter 4).
The bonding between atoms
in compounds changes their

Assorted minerals, including elements such as sulfur
and silver, and compounds such as Al2O3 (sapphire)
and CaF2 (fluorite). Most minerals are impure and exist
as mixtures of different elements and compounds.

The International Union of
Pure and Applied Chemistry
(IUPAC) was formed in
1919 by chemists from
industry and academia.
Since then it has developed
into the world authority
on chemical nomenclature
and terminology. It has
succeeded in fostering
worldwide communications
in the chemical sciences
and in uniting academic,
industrial, and public sector
chemistry in a common
language.
Chemistry is a very
exact subject, and it is
important to be careful
in distinguishing between
upper and lower case
letters. For example, Co
(cobalt, a metallic element)
means something
completely different from

CO (carbon monoxide, a
poisonous gas).
The number of elements
that exist is open to
change as new ones are
discovered, although
there is often a time-lag
between a discovery
and its confirmation by
IUPAC. During this time
a provisional systematic
three-letter symbol is used,
using Latin abbreviations
to represent the atomic
number. The letters u (un)
= 1, b (bi) = 2, t (tri) = 3
and so on are used. So
the provisional element of
atomic number 118 will
continue to be known as
ununoctium or uuo until it
is confirmed and a name
formally agreed according
to the process established
by IUPAC.
A compound is a chemical
combination of different
elements, containing a
fixed ratio of atoms. The
physical and chemical

properties of a compound
are different from those of
its component elements.

5


01

Stoichiometric relationships
properties, so compounds have completely different properties from those of their
component elements.
A classic example of this is that sodium, Na, is a dangerously reactive metal that reacts
violently with water, while chlorine, Cl2, is a toxic gas used as a chemical weapon. Yet when
these two elements combine, they form the compound sodium chloride, NaCl, a white
crystalline solid that we sprinkle all over our food.
Compounds are described using the chemical symbols for elements. A subscript
is used to show the number of atoms of each element in a unit of the compound.
Some examples are given below. (The reasons for the different ratios of elements in
compounds will become clearer after we have studied atomic structure and bonding in
Chapters 2 and 4.)

A combustion spoon holding
sodium, Na, is lowered into
a gas jar containing chlorine,
Cl2. The vigorous reaction
produces white crystals of
sodium chloride, NaCl.
2Na(s) + Cl2(g) → 2NaCl(s)
The properties of the

compound are completely
different from those of its
component elements.

Name of compound

Symbol

Name of compound

Symbol

sodium chloride

NaCl

water

H2O

potassium oxide

K2O

glucose

C6H12O6

calcium bromide

CaBr2

ammonium sulfate

(NH4)2SO4

Chemical equations summarize chemical change
The formation of compounds from elements is an example of chemical change and
can be represented by a chemical equation. A chemical equation is a representation
using chemical symbols of the simplest ratio of atoms, as elements or in compounds,
undergoing chemical change. The left-hand side shows the reactants and the righthand side the products.
calcium + chlorine → calcium chloride
→
Cl2
+
Ca
CaCl2

For example:
A chemical equation
shows:
direction of
change

reactants ⎯→ products
Chemical equations are
the universal language
of chemistry. What other
languages are universal,
and to what extent do they

help or hinder the pursuit
of knowledge?

As atoms are neither created nor destroyed during a chemical reaction, the total number
of atoms of each element must be the same on both sides of the equation. This is known as
balancing the equation, and uses numbers called stoichiometric coefficients to
denote the number of units of each term in the equation.
For example:

hydrogen

+

oxygen

→

water

2H2

+

O2

→

2H2O

coefficients

total on left side

total on right side

hydrogen atoms

4

4

oxygen atoms

2

2

2H2

+

O2

2H2O

Figure 1.1 When hydrogen

and oxygen react to form
water, the atoms are
rearranged, but the number
of atoms of each element

remains the same.

6

+

Note that when the coefficient is 1, this does not need to be explicitly stated.


Chemical equations are used to show all types of reactions in chemistry, including
reactions of decomposition, combustion, neutralization, and so on. Examples of
these are given below and you will come across very many more during this course.
Learning to write equations is an important skill in chemistry, which develops quickly
with practice.

Worked example
Write an equation for the reaction of thermal decomposition of sodium
hydrogencarbonate (NaHCO3) into sodium carbonate (Na2CO3), water (H2O), and
carbon dioxide (CO2).
Solution
First write the information from the question in the form of an equation, and then
check the number of atoms of each element on both sides of the equation.
NaHCO3 → Na2CO3 + H2O + CO2
total on left side

total on right side

1

2

sodium atoms
hydrogen atoms

1

2

carbon atoms

1

2

oxygen atoms

3

6

In order to balance this we introduce coefficient 2 on the left.
2NaHCO3 → Na2CO3 + H2O + CO2

An equation by definition
has to be balanced, so
do not expect this to be
specified in a question.
After you have written an
equation, always check the
numbers of atoms of each

element on both sides of
the equation to ensure it is
correctly balanced.
When a question refers to
‘heating’ a reactant or to
‘thermal decomposition’,
this does not mean the
addition of oxygen, only
that heat is the source of
energy for the reaction.
If the question refers to
‘burning’ or ‘combustion’,
this indicates that oxygen
is a reactant.

Finally check that it is balanced for each element.
NATURE OF SCIENCE
Early ideas to explain chemical change in combustion and rusting included the ‘phlogiston’
theory. This proposed the existence of a fire-like element that was released during these
processes. The theory seemed to explain some of the observations of its time, although these
were purely qualitative. It could not explain later quantitative data showing that substances
actually gain rather than lose mass during burning. In 1783, Lavoisier’s work on oxygen
confirmed that combustion and rusting involve combination with oxygen from the air, so
overturning the phlogiston theory. This is a good example of how the evolution of scientific
ideas, such as how chemical change occurs, is based on the need for theories that can be
tested by experiment. Where results are not compatible with the theory, a new theory must be
put forward, which must then be subject to the same rigour of experimental test.

Exercises
1

Write balanced chemical equations for the following reactions:
(a) The decomposition of copper carbonate (CuCO3) into copper(II) oxide (CuO) and carbon dioxide
(CO2).
(b) The combustion of magnesium (Mg) in oxygen (O2) to form magnesium oxide (MgO).
(c) The neutralization of sulfuric acid (H2SO4) with sodium hydroxide (NaOH) to form sodium sulfate
(Na2SO4) and water (H2O).
(d) The synthesis of ammonia (NH3) from nitrogen (N2) and hydrogen (H2).
(e) The combustion of methane (CH4) to produce carbon dioxide (CO2) and water (H2O).

2

Remember when you are
balancing an equation,
change the stoichiometric
coefficient but never
change the subscript in a
chemical formula.

Write balanced chemical equations for the following reactions:
(a) K + H2O → KOH + H2
(c) Cl2 + KI → KCl + I2
(e) Fe2O3 + C → CO + Fe

(b) C2H5OH + O2 → CO2 + H2O
(d) CrO3 → Cr2O3 + O2

7

01
When balancing
equations, start with the
most complex species, and
leave terms that involve a
single element to last.

Stoichiometric relationships
Exercises
3

Use the same processes to balance the following examples:
(a)
(b)
(c)
(d)
(e)

C4H10 + O2 → CO2 + H2O
NH3 + O2 → NO + H2O
Cu + HNO3 → Cu(NO3)2 + NO + H2O
H2O2 + N2H4 → N2 + H2O + O2
C2H7N + O2 → CO2 + H2O + N2

A chemical equation can be used to assess the efficiency of a reaction in making a
particular product. The atom economy is a concept used for this purpose and is
defined as:
% atom economy =

mass of desired product

total mass of products

× 100

Note that this is different from % yield discussed later in this chapter, which is calculated
using only one product and one reactant. Atom economy is an indication of how
much of the reactants ends up in the required products, rather than in waste products.
A higher atom economy indicates a more efficient and less wasteful process. The
concept is increasingly used in developments in green and sustainable chemistry. This is
discussed further in Chapters 12 and 13.

Mixtures form when substances combine without
chemical interaction
A mixture is composed
of two or more
substances in which no
chemical combination
has occurred.

Tide of oily water heading
towards Pensacola Beach,
Florida, USA, after the
explosion of the offshore
drilling unit in the Gulf of
Mexico in 2010. The oil forms
a separate layer as it does not
mix with the water.

8

Air is described as a mixture of gases because the separate components – different
elements and compounds – are interspersed with each other, but are not chemically
combined. This means, for example, that the gases nitrogen and oxygen when mixed
in air retain the same
characteristic properties
as when they are in the
pure form. Substances
burn in air because the
oxygen present supports
combustion, as does pure
oxygen.
Another characteristic
of mixtures is that their
composition is not fixed.
For example, air that
we breathe in typically
contains about 20% by
volume oxygen, whereas
the air that we breathe
out usually contains
only about 16% by
volume oxygen. It is
still correct to call both
of these mixtures of
air, because there is no
fixed proportion in the
definition.


Air is an example of a homogeneous mixture, meaning that it has uniform

composition and properties throughout. A solution of salt in water and a metal alloy
such as bronze are also homogeneous. By contrast, a heterogeneous mixture such
as water and oil has non-uniform composition, so its properties are not the same
throughout. It is usually possible to see the separate components in a heterogeneous
mixture but not in a homogeneous mixture.
Because the components retain their individual properties in a mixture, we can
often separate them relatively easily. The technique we choose to achieve this will
take advantage of a suitable difference in the physical properties of the components,
as shown in the table below. Many of these are important processes in research and
industry and are discussed in more detail in the following chapters.
Mixture

Difference in property of
components

Technique used

sand and salt

solubility in water

solution and filtration

hydrocarbons in crude oil

boiling point

fractional distillation

iron and sulfur

magnetism

response to a magnet

pigments in food colouring

adsorbtion to solid phase

paper chromatography

different amino acids

net charge at a fixed pH

gel electrophoresis

Matter exists in different states determined by the
temperature and the pressure
From our everyday experience, we know that all matter (elements, compounds, and
mixtures) can exist in different forms depending on the temperature and the pressure.
Liquid water changes into a solid form, such as ice, hail, or snow, as the temperature drops
and it becomes a gas, steam, at high temperatures. These different forms are known as the
states of matter and are characterized by the different energies of the particles.

Ocean oil spills are usually
the result of accidents
in the industries of oil
extraction or transport.
The release of significant

volumes of oil causes
widespread damage to the
environment, especially
wildlife, and can have a
major impact on local
industries such as fishing
and tourism. Efforts to
reduce the impact of the
spill include the use of
dispersants, which act
somewhat like soap in
helping to break up the
oil into smaller droplets
so it can mix better
with water. Concern is
expressed, however, that
these chemicals may
increase the toxicity of the
oil and they might persist
in the environment. The
effects of an oil spill often
reach countries far from
the source and are the
subject of complex issues
in international law. With
the growth in demand for
offshore drilling for oil and
projected increases in oil
pipelines, these issues are
likely to become all the

more pressing.

Figure 1.2 Representation

of the arrangement of the
particles of the same substance
in the solid, liquid, and gas
states.

solid

liquid

gas

increasing temperature
increasing kinetic energy of particles

• particles close packed
• inter-particle forces
strong, particles vibrate
in position

• fixed shape
• fixed volume

• particles more spaced
• inter-particle forces
weaker, particles can
slide over each other

• no fixed shape
• fixed volume

• particles spread out
• inter-particle forces
negligible, particles move
freely

• no fixed shape
• no fixed volume

Depending on the
chemical nature of the
substance, matter may
exist as atoms such as
Ar(g), or as molecules
such as H2O(l), or as
ions such as Na+ and
Cl– in NaCl(aq). The term
particle is therefore used
as an inclusive term that is
applied in this text to any
or all of these entities of
matter.

9


01

Temperature is a
measure of the average
kinetic energy of the
particles of a substance.

Stoichiometric relationships
This is known as the kinetic theory of matter. It recognizes that the average kinetic
energy of the particles is directly related to the temperature of the system. The state of
matter at a given temperature and pressure is determined by the strength of forces that
may exist between the particles, known as inter-particle forces. The average kinetic
energy is proportional to the temperature in Kelvin, introduced on page 37.

Worked example
Which of the following has the highest average kinetic energy?
A

He at 100 °C

B

H2 at 200 °C

C

O2 at 300 °C

D

H2O at 400 °C

Solution
Answer = D. The substance at the highest temperature has the highest average
kinetic energy.
Liquids and gases are referred to as fluids, which refers to their ability to flow. In the
case of liquids it means that they take the shape of their container. Fluid properties
are why diffusion occurs predominantly in these two states. Diffusion is the process
by which the particles of a substance become evenly distributed, as a result of their
random movements.
Kinetic energy (KE) refers to the energy associated with movement or motion. It is
determined by the mass (m) and velocity or speed (v) of a substance, according to the
relationship:
KE= ½ mv2
As the kinetic energy of the particles of substances at the same temperature is equal,
this means there is an inverse relationship between mass and velocity. This is why
substances with lower mass diffuse more quickly than those with greater mass, when
measured at the same temperature. This is discussed in more detail in Chapter 14.
State symbols are used to show the states of the reactants and products taking part in
a reaction. These are abbreviations, which are given in brackets after each term in an
equation, as shown below.
Bromine liquid, Br2(l), had
been placed in the lower
gas jar only, and its vapour
has diffused to fill both jars.
Bromine vaporizes readily at
room temperature and the
gas colour allows the diffusion
to be observed. Because
gas molecules can move
independently of each other
and do so randomly, a gas

spreads out from its source in
this way.

State

Symbol

Example

solid

(s)

Mg(s)

liquid

(l)

Br2(l)

gas

(g)

N2(g)

aqueous (dissolved in water)

(aq)

HCl(aq)

For example:
2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)

Exercises
4

Classify the following mixtures as homogeneous or heterogeneous:
(a) sand and water
(c) sugar and water
(e) ethanol and water in wine

10

(b) smoke
(d) salt and iron filings
(f) steel


Exercises
5

Write balanced equations for the following reactions and apply state symbols to all reactants and
products, assuming room temperature and pressure unless stated otherwise. If you are not familiar
with the aqueous solubilities of some of these substances, you may have to look them up.
(a)
(b)
(c)

(d)
(e)

KNO3 → KNO2 + O2 (when heated, 500°C)
CaCO3 + H2SO4 → CaSO4 + CO2 + H2O
Li + H2O → LiOH + H2
Pb(NO3)2 + NaCl → PbCl2 + NaNO3 (all reactants are in aqueous solution)
C3H6 + O2 → CO2 + H2O (combustion reaction)

6

A mixture of two gases, X and Y, which both have strong but distinct smells, is released. From across
the room the smell of X is detected more quickly than the smell of Y. What can you deduce about X
and Y?

7

Ice floats on water. Comment on why this is not what you would expect from the kinetic theory
of matter.

It is good practice to
show state symbols in all
equations, even when
they are not specifically
requested.

Matter changes state reversibly
As the movement or kinetic energy of the particles increases with temperature, they will
overcome the inter-particle forces and change state. These state changes occur at a fixed
temperature and pressure for each substance, and are given specific names shown below.

sublimation
evaporating/boiling

melting

solid

liquid

gas
condensing

freezing
deposition

Sublimation, the direct inter-conversion of solid to gas without going through
the liquid state, is characteristic at atmospheric pressure of some substances such
as iodine, carbon dioxide, and ammonium chloride. Deposition, the reverse of
sublimation that changes a gas directly to solid, is responsible for the formation of
snow, frost, and hoar frost.

Drying clothes. The heat of the
Sun enables all the water to
evaporate from the clothes.

Note that evaporation involves the change of liquid to gas, but, unlike boiling,
evaporation occurs only at the surface and takes place at temperatures below the
boiling point.

Ice crystals, known as Hair Ice,

formed by deposition on dead
wood in a forest on Vancouver
Island, Canada.

11


01

Stoichiometric relationships

Figure 1.3 Graph showing the

increase in vapour pressure
with temperature. This
explains why boiling point
changes with pressure. The
boiling point of water at three
different pressures is shown.

A pressure cooker is a
sealed container in which
a higher pressure can be
generated. This raises the
boiling point of water and
so cooking time decreases.
Conversely, at altitude,
where the atmospheric
pressure is lower, the
boiling point of water is

reduced so it takes much
longer to cook food.

vapour pressure/Pa

Boiling, on the other hand, is a volume phenomenon, characterized by particles
leaving throughout the body of the liquid – which is why bubbles occur. Boiling
occurs at a specific temperature, determined by when the vapour pressure reaches the
external pressure. The influence of pressure on the temperature at which this occurs is
demonstrated in Figure 1.3.
high pressure
e.g. in a pressure
cooker
atmospheric
pressure
(1.00 × 105 Pa)
lower pressure
e.g. Mt Everest
−20

0

20
40
60
80
100
120
temperature/°C
boiling point

boiling point of
of water in a
water on summit
pressure cooker
of Mt Everest

A butane gas camping stove.
Butane, C4H10, is stored as
a liquid because the high
pressure in the canister raises
its boiling point. When the
valve is opened the release of
pressure causes the butane to
boil, releasing a gas that can
be burned.

CHALLENGE
YOURSELF
1 Propane (C3H8) and butane
(C4H10) are both commonly
used in portable heating
devices. Their boiling points
are butane –1 °C and
propane –42 °C. Suggest
why butane is less suitable
for use in very cold climates.

12

Macrophotograph of freeze-dried instant coffee

granules.
Freeze-drying is an effective process for the preservation of food and some
pharmaceuticals. It differs from standard methods of dehydration in that it does not use
heat to evaporate water, but instead depends on the sublimation of ice. The substance
to be preserved is first frozen, and then warmed gently at very low pressure which
causes the ice to change directly to water vapour. The process is slow but has the
significant advantage that the composition of the material, and so its flavour, are largely
conserved. The freeze-dried product is stored in a moisture-free package that excludes
oxygen, and can be reconstituted by the addition of water.