Cambridge International AS and A Level Chemistry Revision Guide

273 Pages·2011·10.24 MB·English

CAMBRIDGE INTERNATIONAL AS AND A LEVEL
CHEMISTRY
REVISION GUIDE
David Bevan
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Cambridge International AS and A Level Chemistry Revision Guide
Contents
Introduction
About this guide ........................................................................................................... 5
The syllabus ................................................................................................................. 5
Assessment .................................................................................................................. 6
Scientific language ...................................................................................................... 8
Revision ........................................................................................................................ 8
The examination ......................................................................................................... 10
n n n
Content Guidance
1 Atoms, molecules and stoichiometry ................................................................... 14
2 Atomic structure .................................................................................................. 23
3 Chemical bonding ................................................................................................ 29
4 States of matter .................................................................................................... 39
5 Chemical energetics .............................................................................................. 49
6 Electrochemistry .................................................................................................. 56
7 Equilibria ............................................................................................................... 67
8 Reaction kinetics ................................................................................................... 78
9 Chemical periodicity ............................................................................................ 86
10 Group chemistry ................................................................................................... 93
11 The transition elements ...................................................................................... 104
12 Nitrogen and sulfur ............................................................................................. 113
13 Introduction to organic chemistry ...................................................................... 118
14 Hydrocarbons ...................................................................................................... 130
15 Halogen and hydroxy compounds ...................................................................... 139
16 Carbonyl compounds .......................................................................................... 149
17 Carboxylic acid and their derivatives ................................................................. 154
18 Nitrogen compounds ........................................................................................... 163
AS/A-level Chemistry
19 Polymerisation .................................................................................................... 170
20 Applications of chemistry ................................................................................... 175
Experimental Skills & Investigations
Paper 3: AS practical paper ...................................................................................... 219
Paper 5: A2 assessment ........................................................................................... 225
n n n
Questions & Answers
About this section ..................................................................................................... 230
AS exemplar paper .................................................................................................... 231
A2 exemplar paper ................................................................................................... 244
'Try this yourself' answers ....................................................................................... 269
n n n
Cambridge International AS and A Level Chemistry Revision Guide
Introduction
About this guide
This book is intended to help you to prepare for your University of Cambridge
International AS and A level chemistry examinations. It is a revision guide, which
you can use alongside your usual textbook as you work through your course, and
also towards the end when you are revising for your examination.
The guide has four main sections:
●● This Introduction contains an overview of the AS and A2 chemistry courses
and how they are assessed, some advice on revision and advice on the question
papers.
●● The Content Guidance provides a summary of the facts and concepts that you
need to know for the AS and A2 chemistry examinations.
●● The Experimental Skills section explains the data-handling skills you will
need to answer some of the questions in the written papers. It also explains the
practical skills that you will need in order to do well in the practical examination.
●● The Questions and Answers section contains practice examination papers
for you to try. There is also a set of students’ answers for each question, with
comments from an examiner.
There are a number of ways to use this book. We suggest you start by reading through
this Introduction, which will give you some suggestions about how you can improve
your knowledge and skills in chemistry and about some good ways of revising. It also
gives you pointers into how to do well in the examination. The Content Guidance
will be especially useful when you are revising, as will the Questions and Answers.
The syllabus
It is a good idea to have your own copy of the University of Cambridge International
Examinations (CIE) AS and A level chemistry syllabus. You can download it from
http://www.cie.org.uk/qualifications/academic/uppersec/alevel/
The Syllabus Content provides details of the chemical facts and concepts that you
need to know, so keep a check on this as you work through your course. The Syllabus
Content is divided into 25 sections, 1 to 11.3. Each section contains many learning
outcomes. If you feel that you have not covered a particular learning outcome, or if
you feel that you do not understand something, it is a good idea to work to correct
this at an early stage. Don’t wait until revision time!
Do look through all the other sections of the syllabus as well. There is a useful section
on Glossary of terms used in science papers and another giving resources to
help you in your study.
5
introduction
Introduction
Syllabus content
The content of the A-level syllabus is divided into 25 sections:
Topic 1 Atoms, molecules and stoichiometry
Topic 2 Atomic structure
Topic 3 Chemical bonding
Topic 4 States of matter
Topic 5 Chemical energetics
Topic 6 Electrochemistry
Topic 7 Equilibria
Topic 8 Reaction kinetics
Topic 9.1 The periodic table: chemical periodicity
Topic 9.2 Group II
Topic 9.3 Group IV
Topic 9.4 Group VII
Topic 9.5 An introduction to the chemistry of transition elements
Topic 9.6 Nitrogen and sulfur
Topic 10.1 Introductory organic chemistry
Topic 10.2 Hydrocarbons
Topic 10.3 Halogen derivatives
Topic 10.4 Hydroxy compounds
Topic 10.5 Carbonyl compounds
Topic 10.6 Carboxylic acids and derivatives
Topic 10.7 Nitrogen compounds
Topic 10.8 Polymerisation
Topic 11.1 The chemistry of life
Topic 11.2 Applications of analytical chemistry
Topic 11.3 Design and materials
The main part of this book, the Content Guidance, summarises the facts and concepts
covered by the learning outcomes in all of these 25 sections. Some of these sections
deal only with AS material and some with just A2 material. Most chapters contain
aspects of both AS and A2, and the A2 material is clearly indicated by a bar in the
margin.
Assessment
The AS examination can be taken at the end of the first year of your course, or with
the A2 examination papers at the end of the second year of your course.
What is assessed?
Both the AS and A2 examinations will test three Assessment Objectives. These are:
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Cambridge International AS and A Level Chemistry Revision Guide
A: Knowledge with understanding
This involves your knowledge and understanding of the facts and concepts described
in the learning outcomes in all of the 25 sections. Questions testing this Assessment
Objective will make up 46% of the whole A-level examination.
B: Handling information and solving problems
This requires you to use your knowledge and understanding to answer questions
involving unfamiliar contexts or data. The examiners ensure that questions testing
this Assessment Objective cannot have been practised by candidates. You will have
to think to answer these questions, not just remember! An important part of your
preparation for the examination will be to gain confidence in answering this kind
of question. Questions testing this Assessment Objective will make up 30% of the
whole examination.
C: Experimental skills and investigations
This involves your ability to do practical work. The examiners set questions that
require you to carry out experiments. It is most important that you take every oppor-
tunity to improve your practical skills as you work through your course. Your teacher
should give you plenty of practice doing practical work in a laboratory. Questions
testing this Assessment Objective will make up 24% of the whole A-level examina-
tion. This Assessment Objective is assessed in the AS practical paper (Paper 3) and
in Paper 5 at A2.
Notice that more than half of the marks in the examination — 54% — are awarded for
Assessment Objectives B and C. You need to work hard on developing these skills, as
well as learning facts and concepts. There is guidance about this on pages 219–228
of this book.
The examination
The AS examination has three papers:
●● Paper 1 Multiple choice
●● Paper 2 Structured questions
●● Paper 3 Advanced practical skills
Paper 1 and Paper 2 test Assessment Objectives A and B. Paper 3 tests Assessment
Objective C.
Paper 1 contains 40 multiple-choice questions. You have 1 hour to answer this
paper. This works out at about one question per minute, with time left over to go
back through some of the questions again.
Paper 2 contains structured questions. All the questions must be answered. You
write your answers on the question paper. You have 1 hour 15 minutes to answer
this paper.
Paper 3 is a practical examination. You will work in a laboratory. As for Paper 2,
you write your answers on lines provided in the question paper. You have 2 hours to
answer this paper.
7
introduction
Introduction
The A2 examination has two papers:
●● Paper 4 Structured questions
●● Paper 5 Planning, analysis and evaluation
Paper 4 tests Assessment Objectives A and B. Paper 5 tests Assessment Objective C.
Paper 4 has two sections and you have 2 hours to complete it. All the questions must
be answered. You write your answers on the question paper.
Paper 5 contains a number of questions based on the practical skills, including
planning, analysis and evaluation. As for Paper 4, you write your answers on lines
provided in the question paper. Note that this is not a practical examination.
You can find copies of past papers at
http://www.cambridgestudents.org.uk/subjectpages/chemistry/asalchemistry/
pastpapers/
Scientific language
Throughout your chemistry course, and especially in your examination, it is impor-
tant to use clear and correct chemical language. Scientists take great care to use
language precisely. If doctors or researchers do not use exactly the right word when
communicating with someone, then what they say could easily be misinterpreted.
Chemistry has a huge number of specialist terms and symbols and it is important
that you learn them and use them correctly.
However, the examiners are testing your knowledge and understanding of chemistry,
not how well you can write in English. They will do their best to understand what
you mean, even if some of your spelling and grammar is not correct. Nevertheless,
there are some words that you really must spell correctly, because they could be
confused with other chemical terms. These include:
●● words that differ from one another by only one letter, for example ethane and
ethene
●● words with similar spellings but different meanings, for example homogeneous
and homolytic; catalysis and catalase; sulfurous and sulfuric; phosphorus and
phosphorous
In the Syllabus Content section of the syllabus, the words for which you need to
know definitions are printed in italic. You will find definitions of most of these words
in this text.
Revision
You can download a revision checklist at
http://www.cambridgestudents.org.uk/subjectpages/chemistry/asalchemistry/
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Cambridge International AS and A Level Chemistry Revision Guide
This lists all of the learning outcomes, and you can tick them off or make notes
about them as your revision progresses.
There are many different ways of revising, and what works well for you may not be
as suitable for someone else. Have a look at the suggestions below and try some of
them out.
●● Revise continuously. Don’t think that revision is something you do just before
the exam. Life is much easier if you keep revision ticking along all through your
chemistry course. Find 15 minutes a day to look back over work you did a few
weeks ago, to keep it fresh in your mind. You will find this very helpful when you
come to start your intensive revision.
●● Understand it. Research shows that people learn things much more easily if the
brain recognises that they are important and that they make sense. Before you
try to learn a topic, make sure that you understand it. If you don’t, ask a friend or
a teacher, find a different textbook in which to read about it, or look it up on the
internet. Work at it until you feel you have got it sorted and then try to learn it.
●● Make your revision active. Just reading your notes or a textbook will not do
any harm, but nor will it do much good either. Your brain only puts things into
its long-term memory if it thinks they are important, so you need to convince it
that they are. You can do this by making your brain do something with what you
are trying to learn. So, if you are revising from a table comparing the reactions
of alkanes and alkenes, try rewriting it as a paragraph of text, or converting it
into two series of equations. You will learn much more by constructing your own
list of bullet points, flow diagram or table than just trying to remember one that
someone else has constructed.
●● Fair shares for all. It is not a good idea to always start your revision in the
same place. If you always start at the beginning of the course, then you will
learn a great deal about atoms but not very much about organic chemistry or
applications of chemistry. Make sure that each part of the syllabus gets its fair
share of your attention and time.
●● Plan your time. You may find it helpful to draw up a revision plan, setting out
what you will revise and when. Even if you don’t stick to it, it will give you a
framework that you can refer to. If you get behind with it, you can rewrite the
next parts of the plan to squeeze in the topics you have not yet covered.
●● Keep your concentration. It is often said that it is best to revise in short
periods, say 20 minutes or half an hour. This is true for many people who find it
difficult to concentrate for longer than that. But there are others who find it better
to settle down for a much longer period of time — even several hours — and
really get into their work and stay concentrated without interruptions. Find out
which works best for you. It may be different at different times of the day. Maybe
you can concentrate well for only 30 minutes in the morning, but are able to get
lost in your work for several hours in the evening.
●● Don’t assume you know it. The topics in which exam candidates are least
likely to do well are often the ones that they have already learned something
about at GCSE, IGCSE or O-level. This is probably because if you think you
9
introduction