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Teacher Guide
Cambridge IGCSE®
Chemistry
0620
Cambridge Secondary 2
Cambridge International Examinations retains the copyright on all its publications. Registered Centres are
permitted to copy material from this booklet for their own internal use. However, we cannot give permission
to Centres to photocopy any material that is acknowledged to a third party even for internal use within a
Centre.
® IGCSE is the registered trademark of Cambridge International Examinations.
© Cambridge International Examinations 2013
Contents
Introduction ...................................................................................................................... 3
Section 1: Syllabus overview ............................................................................................... 5
1.1
1.2
1.3
1.4
1.5
Aims
Assessment objectives
The assessment structure
Curriculum content
Practical assessment
Section 2: Planning the course .......................................................................................... 11
2.1
2.2
2.3
2.4
Key factors to consider when planning your course
Long-term planning
Medium-term planning
Short-term planning
Section 3: Planning lessons ............................................................................................... 15
3.1 Lesson plans and templates
3.2 Constructing a lesson plan
3.3 Reflection and evaluation
Section 4: Classroom practice ........................................................................................... 17
4.1 Practical lessons
4.2 Active learning
4.3 Differentiation
Section 5: Preparing learners for final assessment ............................................................ 21
5.1
5.2
5.3
5.4
5.5
Use of past papers, mark schemes and principal examiner reports
Paper 1
Papers 2 and 3
Practical alternatives
Command words
Section 6: Resources and support ..................................................................................... 23
6.1
6.2
6.3
6.4
Finding and evaluating resources
Teacher Support
Coursework Training Handbooks
Training
Appendices ..................................................................................................................... 25
Appendix A: Teaching syllabus version 1
Appendix B: Teaching syllabus version 2
Appendix C: Sample medium-term plan
Appendix D: Sample lesson plan template
Appendix E: Sample plan for a 70 minute lesson on the order of reactivity
Appendix F: Suggested practical activities
Introduction
Introduction
The purpose of the teacher guide
This teacher guide is designed to introduce you to the IGCSE Chemistry syllabus and support materials from
Cambridge. It will help you to organise and plan your teaching. It also offers advice and guidance on delivery,
classroom practice (including practical work) and preparing your learners for their final assessment.
What do I need to get started?
When planning your course, your starting point should be the syllabus, which contains a large quantity of
essential information. It is most important that you become thoroughly familiar with all parts of the syllabus
document.
You then need to devise a scheme of work. To do this, you need to think how you will organise the time
that you have available to help students to understand and learn all of the facts and concepts required by
the syllabus, and to develop the skills – such as handling data and planning experiments – that are also
required. Cambridge provides a sample scheme of work that you could use as a starting point, but you will
undoubtedly want to produce your own at some point.
Your scheme of work will help you to determine what resources you will require to deliver the course. You
need to ensure that you have sufficient laboratory facilities to allow learners to carry out the practical work
that is needed. You will also need to build up teaching, learning and reference resources such as text books
and worksheets.
You should make sure, at an early stage, that you have access to the secure online support available
to Cambridge teachers, Teacher Support, at http://teachers.cie.org.uk. This provides a wide range of
resources to help you, including past examination papers, mark schemes and examiner reports. All of these
are invaluable in helping you and your learners to understand exactly what Cambridge expects of candidates
in examinations, which will help you to prepare your students appropriately.
This Guidance Document provides suggestions and help with all of these aspects of planning your IGCSE
Chemistry course.
Please have your copy of the most recent syllabus with you as you read through this document, as
you will need to refer to it frequently. References indicate the relevant pages of the syllabus, and also
other documents to which you should refer as you work through this guide.
Cambridge IGCSE Chemistry 0620
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Introduction
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Cambridge IGCSE Chemistry 0620
Section 1: Syllabus overview
Section 1: Syllabus overview
1.1 Aims
The syllabus aims, which are not in order of priority, are listed at the start of Section 3 in the syllabus.
The aims provide you with an overview of what Cambridge expects learners to experience and achieve
as they follow their IGCSE Chemistry course. You should bear these in mind as you plan your scheme of
work. Notice that many of the aims relate to attitudes and skills, rather than simply the accumulation of
knowledge. A Cambridge IGCSE Chemistry learner should develop attitudes and skills that will be useful in
many areas of their life, long after they have taken their IGCSE Chemistry examinations.
1.2 Assessment objectives
The assessment objectives are statements about what will actually be tested in the final examinations. Each
question or task that is set in the examination relates to one or more of these assessment objectives (AOs).
All of the IGCSE Science syllabuses have the same three AOs. These are:
A: Knowledge with understanding
B: Handling information and problem solving
C: Experimental skills and investigations
Each of these AOs has several components.
A: Knowledge with understanding
Candidates should be able to demonstrate knowledge and understanding of:
1. scientific phenomena, facts, laws, definitions, concepts, theories
2. scientific vocabulary, terminology, conventions (including symbols, quantities and units)
3. scientific instruments and apparatus, including techniques of operation and aspects of safety
4. scientific quantities and their determination
5. scientific and technological applications with their social, economic and environmental applications
The knowledge that learners should acquire is described in the Contents section of the syllabus.
B: Handling information and problem solving
Candidates should be able, using oral, written, symbolic, graphical and numerical forms of presentation, to:
1. locate, select, organise and present information from a variety of sources
2. translate information from one form to another
3. manipulate numerical and other data
4. use information to identify patterns, report trends and draw inferences
5. present reasoned explanations of phenomena, patterns and relationships
Cambridge IGCSE Chemistry 0620
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Section 1: Syllabus overview
6. make predictions and propose hypotheses
7. solve problems, including some of a quantitative nature
Questions testing AO B will frequently be based on contexts and information that are unfamiliar to
candidates. They will require candidates to apply the facts, principles and concepts that they have learnt
(specified in the syllabus content) to new situations. Candidates need to develop confidence in applying their
knowledge and understanding in a logical way, using reasoning or calculation to deduce suitable answers.
This means that your course needs to do much more than simply teach learners the material described
in the Contents section of the syllabus. It must also help them to develop these skills of reasoning and
deduction.
C: Experimental skills and investigations
Candidates should be able to:
1. know how to use techniques, apparatus and materials (including following a sequence of instructions,
where appropriate)
2. make and record observations and measurements
3. interpret and evaluate experimental observations and data
4. plan investigations, evaluate methods and suggest possible improvements (including the selection of
techniques, apparatus and materials).
The development of experimental skills (scientific enquiry skills) should be an important part of your scheme
of work. Learners should have the opportunity to do a wide range of practical work throughout their course.
Some of this will require laboratory facilities and equipment, but there are some practical activities in
Chemistry that can be done in a normal classroom.
1.3 The assessment structure
It is a good idea, right from the start of planning your IGCSE Chemistry course, to make sure that you have
a full understanding of how your learners will be assessed by Cambridge at the end of it. There are choices
to be made about which papers students can be entered for. You do not need to make final decisions about
these straight away – they are made when you actually enter your learners for the examinations, a few
months before the examination period – but you should keep them in mind as you construct your scheme of
work and lesson plans.
Each learner will need to take three components, called ‘papers’.
Paper 1
All candidates take Paper 1. This is a multiple-choice paper. The questions are set on the Core syllabus
content only. The questions test AO A and AO B. The Paper is taken in an examination room, under strict
examination conditions. The completed answer sheets are sent to Cambridge to be marked.
Paper 2 or Paper 3
Each candidate takes either Paper 2 or Paper 3. These are both made up of structured questions, which
test AO A and AO B. The papers are taken in an examination room, under strict examination conditions. The
completed papers are sent to Cambridge to be marked.
You need to be aware of the differences between these two papers.
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Cambridge IGCSE Chemistry 0620
Section 1: Syllabus overview
Paper 2 is easier than Paper 3. This is because:
•
Paper 2 tests candidates on their knowledge and understanding of the Core syllabus content only, while
Paper 3 tests them on their knowledge and understanding of the Core and Supplement content. (See
1.4.1 for an explanation of Core and Supplement content.)
•
Paper 2 tends to contain questions that are slightly less demanding in terms of reasoning skills than
Paper 3. The questions tend to be shorter, contain less reading for candidates, and require shorter
answers.
•
However many marks candidates obtain on Paper 2, they cannot achieve more than a Grade C.
Candidates taking Paper 3 can achieve any grade from A* down to G.
An understanding of the differences between these two papers will help you to decide on whether you
will teach both the Core and Supplement syllabus content, or the Core only. Candidates who are unlikely
to get a Grade C are likely to achieve a better grade if they study only the Core and take Paper 2. However,
candidates who you think stand a good chance of achieving a Grade C or above should study both Core and
Supplement (known as the ‘Extended Curriculum’), and take Paper 3. This is also important for candidates
who are likely to want to continue their studies of Chemistry beyond IGCSE.
Paper 4, Paper 5 or Paper 6
Each candidate takes either Paper 4, Paper 5 or Paper 6. These all test AO C, Experimental skills and
investigations. (See also section 1.5 Practical assessment)
Paper 4 is not really a ‘paper’ at all. If you choose to enter candidates for Paper 4, you will assess their
practical skills throughout the course. The details of how this should be done are explained in the booklet
Coursework Training Handbook (Part 1): Guidance. If you are not familiar with coursework assessment, it is
recommended that you also obtain and work through the Coursework Training Handbook (Part 2): Teacher
Accreditation.
Paper 5 is a practical examination. Several weeks before the examination is taken, Cambridge will send you
a list of apparatus and materials that you need to supply. During the examination, your candidates will work
in a laboratory, each with their own working space and set of apparatus, under strict examination conditions.
They will write their answers in an examination paper, just as they would for a theory examination. The
examination paper is sent back to Cambridge to be marked.
Paper 6 is a written paper. It looks just like Paper 2 or Paper 3, but it tests AO C. The questions test
learners’ experience of practical work. The paper is taken in a normal examination room, and is sent to
Cambridge to be marked.
Cambridge IGCSE Chemistry 0620
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Section 1: Syllabus overview
Weightings
The ‘weighting’ of a paper tells you the relative importance of that paper in deciding the candidate’s overall
mark and final grade.
The table below summarises the weightings of the three components that a candidate will take at the end
of their course.
Paper
Weighting
Paper 1
30%
Paper 2 or Paper 3
50%
Paper 4 or Paper 5 or Paper 6
20%
You will remember that Paper 1, Paper 2 and Paper 3 test largely AO A and AO B.
The table below summarises how the three assessment objectives are tested in the three examination
components. It also shows the weighting of the three AOs in the whole examination.
Assessment Objective
Paper 1
(marks)
Papers
2 or 3
(marks)
Papers
4, 5 or 6
(marks)
Whole
assessment
(%)
A: Knowledge with understanding
25–30
48–52
0
47–54
B: Handling information and problem solving
10–15
28–32
0
26–33
0
0
40
20
C: Experimental skills and investigations
If you look at the final column of the table above, you can see that:
•
Assessment Objective A makes up about 50% of the whole assessment.
•
Assessment Objective B makes up about 30% of the whole assessment.
•
Assessment Objective C makes up about 20% of the whole assessment.
This means that only half of the total marks in the three examination papers are for knowledge and
understanding of the syllabus content. Half of the marks are for being able to use this knowledge and
understanding in new contexts, and for experimental skills. It is essential to bear this in mind as you plan
your IGCSE Chemistry course. You need to spend at least as much time helping students to develop their
AO B and AO C skills, as in helping them to learn facts and concepts.
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Cambridge IGCSE Chemistry 0620
Section 1: Syllabus overview
1.4 Curriculum content
The largest section in the syllabus is Section 4, Curriculum content. It is here that you will find details of
exactly what your learners need to know and understand by the end of the course. It is presented as a
series of bullet points (learning objectives) which state clearly what candidates should be able to do in
the examination papers that they take at the end of their course. Each question that is included in the
examination papers tests one or more of these learning objectives.
You should read each learning objective very carefully. Each one gives you clear guidance about exactly
what candidates should learn. Some of them provide definitions of important biological terms, and these are
the definitions that your learners should use.
1.4.1 Core and supplement
One of the first things you will notice about the curriculum content is that it is presented in two columns. The
left hand column is the ‘Core’ content. All candidates need to cover all of this. This will be tested in all papers.
The right hand column is the ‘Supplement’ content. All candidates who you think are likely to achieve a good
Grade C or above should cover all of this, as well as the Core. The Core plus Supplement makes up the
Extended curriculum. This will be tested only in Paper 3.
1.4.2 Syllabus content
The syllabus content has fourteen main sections.
Section 1: The particulate nature of matter
Section 2: Experimental techniques
Section 3: Atoms, elements and compounds
Section 4: Stoichiometry
Section 5: Electricity and chemistry
Section 6: Chemical energetics
Section 7: Chemical reactions
Section 8: Acids, bases and salts
Section 9: The Periodic Table
Section 10: Metals
Section 11: Air and water
Section 12: Sulfur
Section 13: Carbonates
Section 14: Organic chemistry
These sections vary greatly in their amount of content, e.g. sections 12 and 13 are very short, whereas
sections 9 and 10 contain a great deal. Some sections are relatively free standing, e.g. section 14, whereas
others depend upon each other, e.g. sections 3 and 9. Some sections, e.g. 2 and 4 could be taught as part
of a number of sections throughout the course.
Cambridge IGCSE Chemistry 0620
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Section 1: Syllabus overview
In addition there are three concepts relating the study of Chemistry to everyday life. These should be
incorporated into sections of the syllabus where appropriate.
•
the finite life of the world’s resources and the need for recycling and conservation
•
economic considerations in the chemical industry such as the availability and cost of raw materials and
energy
•
the importance of chemicals in both industry and everyday life
Chemistry is a subject where one topic often depends on a number of others if it is to be understood fully.
For this reason it often does not make sense to study the subject one syllabus section at a time. Studying
the units in the order printed in the syllabus is not recommended.
There is more discussion of alternative ways to organise the syllabus section in the next section (Planning
the course).
1.5 Practical assessment
Section 5 of the syllabus covers each of the alternative ways of assessing practical work in some detail.
Papers 4 and 5 involve actually carrying out practical work, either in class over the time of the course or in a
practical examination at the end of the course. Paper 6 is a written paper designed to assess practical skills.
Candidates entered for Paper 6 should still have experienced plenty of practical work to allow them to
answer this paper properly.
In section 5.2 of the syllabus there is a list of apparatus which will be required by candidates entering for
Paper 5. The availability of this apparatus should be checked before entering candidates for this practical
examination.
Appendix A of the syllabus contains a page of notes to aid the candidates in qualitative analysis. This sheet
can be used in the practical examination, Paper 5, and in class during coursework, Paper 4. It cannot be
used in Paper 6. Candidates entered for this paper will still need to know these tests and their results but
cannot have access to the sheet during the examination.
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Cambridge IGCSE Chemistry 0620
Section 2: Planning the course
Section 2: Planning the course
This section looks at how you can plan your course to ensure that you can cover the whole syllabus
(whether this is to be just the Core, or the Core plus Supplement) within the time that you have available. It
includes long-term planning (developing a scheme of work) and planning for individual lessons.
2.1 Key factors to consider when planning your course
These factors will need to be considered before starting the planning of your course.
•
The amount of teaching time available each week for the duration of the course.
•
The availability of resources such as laboratories and chemical equipment.
•
The previous learning of your students.
•
Whether your teaching groups will be mixed ability or will be streamed by ability.
•
The number of lessons you will need to cover the syllabus (the recommended time for an IGCSE course
is 130 hours of teaching time)
•
The school calendar; holidays, examinations, etc.
2.2 Long-term planning
A long-term plan will provide the overall structure of your course. It will include the order in which topics will
be taught, the approximate length of time to be spent on each and the factors listed in section 2.1 above.
It will need to take into account the number and nature of the groups following the course and if they should
all follow the same path through the course. There may, for example, be issues with the use of laboratory
space if two groups are studying a topic requiring a large amount of practical work at the same time. In this
case it would be better if the plan was organised so that groups could study such a topic at different times.
Topics should also, ideally, be arranged so that they fit into the school’s sessions, so that a topic is not split
because of a school holiday or an examination session.
In a two year course the second year will probably have fewer weeks because of the timing of the
Cambridge examinations.
It is important to note that you do not need to teach the syllabus content in the order in which it is printed
in the syllabus. It is likely that you will want to order your teaching to suit your particular needs and
preferences. This may be done in a number of ways.
•
Starting with the structure of atoms followed by the Periodic Table and then the chemistry of different
elements.
•
Starting with raw materials such as petroleum, air, water carbonates etc. and covering their uses before
the Chemistry theory.
•
Starting with a course in practical techniques to generate enthusiasm.
•
Starting with topics which are conceptually easier, saving the more difficult topics for the second year of
the course.
•
Using the suggested pattern in the ‘schemes of work’ provided on Teacher Support.
•
Following your own interests and enthusiasms to begin with.
Cambridge IGCSE Chemistry 0620
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Section 2: Planning the course
Two possible re-orderings of the syllabus topics are included in the Appendix but these take no account of
your particular situation. The most important thing is to choose a teaching order that suits you, your learners
and the availability of resources at your school.
A long-term plan should also consider how practical skills will be developed and which topics will contribute
largely to the development of these skills. This is particularly important if you intend to follow the Paper 4
route to practical assessment.
A long-term plan is not ‘set in stone’; it is a working document. As the course progresses you can adapt it as
required. When you have worked through it once or twice you will have a much better idea of the best way
for you to work through the syllabus.
2.3 Medium-term planning
Medium-term planning is the most important of the three types. It defines, in some detail, what will be
taught and when. It also details how practical work and other activities are to be incorporated into the
course.
Medium-term plans are often called ‘Schemes of Work’ and these schemes inform you and other Chemistry
teachers in your school what will happen and when.
Some examples of schemes of work can be found on Teacher Support http://teachers.cie.org.uk. A
password is needed to access the site and your Examination Officer will be able to provide you with one.
These schemes of work are useful resources but are not really suitable as an alternative to your own
medium-term planning because:
•
they take no account of the situation in your Centre
•
they are arranged in a way which may not be what you had designed in your long-term plan
•
they have no statement of the amount of time required
•
they have many suggestions for suitable activities and web sites which you would not necessarily have
the time or the resources to follow.
However, they can still be useful.
•
They could be used as they stand as one way of moving through the course, although timings for each
section would have to be added.
•
They are certainly a good source of possible practical exercises and web addresses.
However:
•
Always check URLs before using them. Web addresses do change from time to time and you need to
know what you would be accessing in advance.
•
It is really better to develop your own scheme of work as this is more likely to be suitable for your
Centre and your learners.
An example of a medium-term plan is included in the appendix. Some of the information from the published
Cambridge scheme of work (Unit 06: Metals and the Reactivity Series) is used in the plan.
A medium-term plan is best developed with contributions from all of the teachers who will be using it. If
they have had an input they will feel an ‘ownership’ of the plan and will be more likely to adhere to it.
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Cambridge IGCSE Chemistry 0620
Section 2: Planning the course
A medium-term plan, like a long-term plan, should not be ‘set in stone’. It should, if necessary, be amended
if it is found not to be working as planned. It should certainly be reviewed at the end of each year to assess
how well it has worked and to decide if any improvements could be incorporated.
2.4 Short-term planning
Short-term planning involves planning for a single lesson or perhaps a small group of lessons. It involves not
only the content of the lesson but also the activities which will take place and the progress that is expected
of the learners during the lesson.
Short-term planning is something which is done by an individual teacher, taking into account their own
strengths and the needs of the learners they will be teaching. Teachers new to the subject may need
guidance but the plan should still be their own.
This process is covered in more detail in the next section.
Cambridge IGCSE Chemistry 0620
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Section 2: Planning the course
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Cambridge IGCSE Chemistry 0620
Section 3: Planning lessons
Section 3: Planning lessons
3.1 Lesson plans and templates
A lesson plan is written by the teacher and should include details of how the lesson is intended to proceed.
It should take account of:
•
what is to be taught (learning objectives)
•
what is to be achieved by the learners (lesson objectives)
•
what the learners already know (previous learning).
It should detail the learning activities which will take place and have approximate timings showing how long
each part of the lesson will last.
A lesson should ideally have three main parts:
•
a beginning which engages and motivates the learners
•
a middle which covers the main learning activities of the lesson
•
an end, in which learners can assess their understanding of what has gone before.
It is most convenient to have a printed template to use in lesson planning. You could design your own but
there are many available on the internet or in books. One example is included in the appendix.
3.2 Constructing a lesson plan
1. Learning objectives. This will be based on something written in your medium-term plan. It will state
which part of the syllabus the lesson is going to address.
2. Lesson objectives. These may be the same as the learning objectives but more often will be only a
part of them. This is what you intend the learners to fully grasp by the end of the lesson. It should be a
realistic target and many learning objectives will take more than one lesson to be fully understood.
3. Lesson beginning (starter). This should be a relatively brief part of the lesson and should ‘switch the
learners on’ to Chemistry, rather than what they were doing previously. It may be a short question and
answer session, or a simple written task to assess what they know about the topic to be covered. It
could even be a rapid practical demonstration to introduce them to the topic to be covered in the lesson.
Give an estimated time, usually about five minutes.
4.
Lesson middle (the main activity). This may build on and extend previous understanding, explore and
solve practical problems, develop knowledge and skills, practise previously learned techniques or any of
many other alternatives. It is important not to include too many activities, but equally important not to
spend so much time on one activity that learners become de-motivated. Good lessons will involve the
learners in the activities as much as possible. Timings should be included for each separate activity.
5. Lesson end (plenary). This part of the lesson brings it to an organised conclusion. Learners can assess
how well they understand the material covered during the lesson. This may involve a short written
exercise or a question and answer session. It may also be used to link to whatever is going to happen in
the next session. This should again take around five minutes at most.
Cambridge IGCSE Chemistry 0620
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Section 3: Planning lessons
6. Resources. Your plan should also include a list of the resources (books, internet, practical equipment,
chemicals, etc.) which will be needed in each session of the lesson.
7. Risk Assessment. If your lesson includes any practical activity, whether a demonstration or a class
practical, an assessment of the risks involved should be included with the lesson plan.
8. Assessment of Learning. How will you check:
• what your learners know/understand before the lesson
•
how this has changed after the lesson.
9. Differentiation. How will you try to ensure that the lesson is accessible to all of the learners so that all
will benefit from the experience? This is especially important with mixed ability groups. There is more
on differentiation in the next section.
3.3 Reflection and evaluation
As soon as possible after the lesson you need to think about how well (or badly) it went. There are two
reasons for this; if you share your plan with other teachers in your Centre it will enable them to learn from
your experiences. It is a good idea to discuss with colleagues how well lessons went. This applies whether
they went well or whether there were problems.
It will also help next time you teach the same topic. If the timing was wrong or the activities did not fully
occupy the learners you may want to change some aspects of the lesson next time.
There is no need to re-plan a successful lesson every year, but it is always good to learn from experience
and to incorporate improvements next time.
In the template in the appendix there is a place to record your evaluation of the lesson.
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Cambridge IGCSE Chemistry 0620
Section 4: Classroom practice
Section 4: Classroom practice
The aim of any teacher is to get their learners to gain knowledge and understanding and to develop as many
skills as possible in the time available.
The teaching should also differentiate between the different needs and abilities of the learners in the group.
It is not always possible to fulfil all of these, but it is good to try. Lessons should at least be interesting and
involve the learners as much as possible.
4.1 Practical lessons
Chemistry is, or at least should be, a practical subject. The syllabus does not suggest any particular
experiments which should be undertaken, although sections 2, 7.2, 8.3, 8.4, 9.2 and 10.2 do imply certain
practical activities.
All sections can, however, be enhanced by the use of practical work, and a list of possible practicals linked
to syllabus sections is provided in Appendix F.
Practical work is usually motivating to learners, whether it is a class practical or a teacher demonstration,
but it should always have a purpose other than entertainment. It may
•
develop the skills that the learners need
•
illustrate facts or concepts which are being studied
•
provide a stimulus for further study.
It may, of course accomplish more than one of these.
4.1.1 Class practicals
Ideally such practicals should be carried out in small groups (two or three learners). In this way students
learn to work co-operatively and can also, by discussion, develop their understanding of what is taking
place. Working in groups also means that less equipment is needed.
If you are intending to enter your learners for Paper 4 (coursework assessment) they will need to do at least
some work on their own. Those entering for Paper 5 will also need to practise on their own as this is what
they will need to do in the practical examination.
It is always a good idea to try out a practical activity before asking a class to do it. In this way you can
anticipate the problems that they might discover. It also gives you a good idea of how long the activity might
last; learners will probably take longer than you.
It is important that the instructions you give are clear. Oral instructions are fine for a simple task but if there
are a number of steps involved, a written worksheet is a good idea. Such a sheet can be reused each time
the practical is attempted. Worksheets are also useful to teachers who are new to teaching your scheme.
It is important that learners know why they are carrying out the practical activity. This could be acheived
by giving it a simple title such as ‘How do different metals react with hydrochloric acid?’ or ‘Producing pure
water from sea water’.
Cambridge IGCSE Chemistry 0620
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Section 4: Classroom practice
If time permits, learners should be encouraged to set up their own apparatus and to clear things away
afterwards. This is especially true if your Centre has no help from a science technician to deal with the
preparation of practical lessons.
4.1.2 Demonstration practicals
There are a number of occasions when a practical demonstrated by the teacher in front of the class is
necessary or more appropriate but this type of practical should never replace class practical work. A
practical may be demonstrated
•
where complex or expensive apparatus is needed
•
where the procedure is too dangerous for a class practical
•
where the teacher wishes to demonstrate a technique to be used by the class, e.g. using a pipette and
burette
•
where the teacher wishes to explain what is going on
•
where the teacher wishes to demonstrate a phenomenon which is to be explained subsequently.
The first three are self-explanatory but the final two may need amplification.
It can be a good idea to explain to a class what is happening during an experiment. This may be something
relatively simple like fractional distillation. Explaining each step of the process as it is carried out will produce
more learning than simply letting the candidates carry it out for themselves.
A spectacular demonstration followed by the question ‘Now why did that happen?’ can sometimes be a
good way to introduce a topic. However, the temptation to use flashes, bangs and nasty smells purely for
the sake of it should be resisted.
4.1.3 Risk assessment
It is essential that the risks involved in any practical carried out by a teacher or a learner are assessed. Some
processes, such as burning fuels, are hazardous, as are some chemicals such as acids. These factors should
be taken into account when deciding on a practical activity, as should the situation of the activity. What is
safe in a laboratory may not be safe in a classroom. What is safe for a teacher to do may not be safe in a
class practical. What is safe for one group of learners may not be safe for another.
A risk assessment involves not only the chemicals and what is to be done with them but also who is doing it
and where.
4.2 Active learning
Not every topic in Chemistry can be taught by means of an experiment; atomic structure and chemical
bonding are two, the various industrial processes which need to be explained form another. A description/
explanation by the teacher is easily forgotten by the learner, even if it was understood in the first place.
Videos of the industrial processes and computer animations of the atoms and their bonds can help, but they
are still ‘passive’. The learner is not involved in ‘discovering’ the information.
Research has shown that the more a learner is involved in the process of learning, the more they retain.
The learning pyramid below shows the percentage of information retained as a result of different forms of
delivery stimulating different learning processes.
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Cambridge IGCSE Chemistry 0620
Section 4: Classroom practice
Lecture
Reading: 10%
Audiovisual: 20%
Demonstration: 30%
Discussion: 50%
Practise doing: 75%
Teach others: 90%
From this it will be seen that although audiovisual (videos and computer animations) may be better than
a lecture (being told by a teacher), there are methods which are better still. Clearly not everything can be
absorbed by discussion and practice, but activities where the learners actually participate work better.
At least some such activities (active learning) should be used alongside practical work in order to maximise
learning. There will not be time for everything to be covered in this way but some topics certainly should be.
The Royal Society of Chemistry has developed a series of activities called ‘Alchemy’.
www.rsc.org/education/teachers/resources/alchemy/index2.htm
The industrial processes in the syllabus are included and each topic can be downloaded. There is
information to read, a video to watch and questions to answer. Learners interact with the information
delivered. Different groups could even investigate different processes and then ‘teach’ others by explaining
the process to a different group.
There are, of course, many other methods of getting learners involved and plenty of ideas in books and on
the web.
4.3 Differentiation
Differentiation is a way of trying to ensure that members of your group with differing abilities can all access
the material you are delivering. There are a number of ways of approaching this problem and, again, they
can be found in books and on the web. They fall into three main categories.
•
Differentiation by outcome. In this method an open-ended task is set which can be accessed by all,
e.g. ‘Find out how these metals react with acid’. Learners will produce different results according to
their ability, but all of their ‘outputs’ will be valid.
•
Differentiation by task. Learners are set slightly different tasks based on the same objective. This may
involve worksheets which pose questions on the same topic where differing amounts of understanding
are required.
Cambridge IGCSE Chemistry 0620
19
Section 4: Classroom practice
•
20
Differentiation by support. All learners undertake the same task but those who are weaker are given
additional support; writing frames, where a template is provided for them to record their work, are one
way of doing this.
Cambridge IGCSE Chemistry 0620
Section 5: Preparing learners for final assessment
Section 5: Preparing learners for final assessment
Your Chemistry course will end with your learners being assessed by an external examination. It is clearly a
good idea to ensure that they are prepared as well as possible for this. There are a number of things to bear
in mind when approaching this task.
5.1 Use of past papers, mark schemes and Principal Examiner
Reports
There are plenty of past papers on Teacher Support. These can be downloaded and used to give your
learners practice in answering the type of questions they will meet in the actual examination. There are also
mark schemes which will inform you of which answers were considered correct by the examiners. The
principal examiner’s report for each paper will tell you of common errors made by candidates who sat that
paper.
Work on whole papers should, of course, be done towards the end of your course, but individual questions
can be used as tests at the end of individual topics. This can be useful not only when the topic is first
taught, but also when it is briefly revised at the end of the course.
Examination questions relevant to particular topics are also included as part of the ‘Scheme of Work’ to be
found on Teacher Support.
Examination papers and questions can be set and marked by the teacher but it is also useful to allow
learners to mark their own papers using a mark scheme, or to allow a group of learners to discuss what the
correct answers might be.
There are different things that need to be borne in mind in the different papers.
5.2 Paper 1
Paper 1 consists of forty multiple-choice questions. Each one has four possible responses; the correct
answer and three ‘distractors’. Some of these distractors are, intentionally, very similar to the correct answer
and it is easy to choose the wrong one especially if a candidate does not read all of the possible responses
and instead opts for the first one which seems ‘about right’.
The following are useful pieces of advice for those attempting multiple-choice questions.
•
Never leave an answer blank. No marks are lost for wrong answers.
•
Always read all of the responses before deciding on an answer (see above).
•
Look out for the word ‘not’ as in ‘which of the following is not...’; candidates often get such questions
wrong through carelessness.
•
If you do not know the correct answer, don’t just guess, cross out any which are obviously wrong first. It
is better to guess one of two than one of four.
•
Don’t spend too long thinking about a difficult question; leave it and come back to it later.
Cambridge IGCSE Chemistry 0620
21
Section 5: Preparing learners for final assessment
5.3 Papers 2 and 3
Both of these papers consist of a number of short answer questions together with a smaller number of
questions requiring longer answers. Particularly in Paper 3, you will find questions requiring calculations.
The following are useful pieces of advice for those attempting these papers.
•
If an answer is given more than one mark, more than one piece of information is needed.
•
In answers involving calculations, show your working.
•
The number of lines provided for an answer is a guide to the amount of information required.
5.4 Practical alternatives
5.4.1 Paper 4 Coursework assessment
If you are entering your candidates for this option they will probably have marks for practical assessment ‘in
the bank’. Remember that candidates can be assessed as many times as you wish and that only the best
marks for each skill count.
It is a good idea to do some easy tasks early in the course so that there are some marks which can count if
there are problems later.
5.4.2 Paper 5 Practical examination
The best way to prepare for this is to allow candidates to practise the skills needed by trying a couple of
previous examinations. There is always a quantitative exercise which often involves the drawing of a graph
and there is also always a question involving the use of the ‘test for ions’ sheet.
5.4.3 Paper 6 Alternative to Practical
Going through a few past papers should get candidates used to what is expected, although it is difficult to
prepare for the final question, where candidates have to plan an experiment.
This paper is not too difficult if candidates have had sufficient experience of practical work during their
course. Remember that they need to have memorised the information on the ‘tests for ions’ sheet.
5.5 Command words
In Appendix A of the syllabus (section 6.5) is a list of words which are used in examination papers. These
words (command words) tell the candidate the type of answer that is required. For example, ‘State’ means a
short answer whereas ‘Explain’ indicates that more detail is required; ‘Suggest’ means that the candidate is
not meant to have learned the answer but should try to work one out from what they do know.
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Cambridge IGCSE Chemistry 0620
Section 6: Resources and support
Section 6: Resources and support
6.1 Finding and evaluating resources
There is no shortage of resources to aid the teaching of Chemistry. They can be found in text books and
on the Internet. There are even books that consist entirely of a range of different resources. The problem is
finding one that is effective and that suits your situation. The quality of resources varies widely from ‘home
made’ ones which are uploaded to the internet, to professionally produced ones. The latter are not always
the best.
The problem is not so much finding resources, but evaluating whether they will suit your situation and are
effective.
Perhaps the easiest way to find reliable resources is to get them from a colleague who has already used
them and can tell you how good they are. Sadly this is often not possible.
There are also resources to be found on Cambridge online, more details of which are given later in this
section.
Resources from the Internet and from books need to be scrutinised to see if they are of use. A couple of
websites which each give a wide variety of resources free of charge are given below.
www.nuffieldfoundation.org/practical-chemistry
This site gives detailed descriptions of a large number of practicals together with details of hazards.
Experiments are at many levels, some at a more advanced level than IGCSE, but you will find details of
most of the experiments you might wish to try.
www.rsc.org/learn-chemistry
This site has a huge range of resources of different types. You can search by age group, topic, type of
resource or any combination of these. Remember though that not all resources may be suitable for your
course or your school.
6.2 Teacher Support
This is an excellent source of information. You need a username and password to access it and these can be
obtained from your Examinations Officer if you are in a Cambridge Centre.
On Teacher Support you will be able to access the syllabus and copies of past papers together with
their mark schemes, examiner reports and grade thresholds, and a sample ‘scheme of work’ which can
be downloaded and used to gain further information on the delivery of this syllabus. There is also a list
of resources and a link to the ‘Discussion Forum’ where teachers can post comments and questions. It
is worth looking at this from time to time and following interesting threads even if you do not post any
comments of your own.
6.3 Coursework Training Handbooks
The coursework component of the Cambridge IGCSE Chemistry qualification is marked by the Centre and
moderated by Cambridge. In order to mark, Centres must have at least one accredited teacher registered
with Cambridge.
Cambridge IGCSE Chemistry 0620
23
Section 6: Resources and support
Cambridge provides a dedicated coursework guide called the: Coursework Training Handbook (Part 1):
Guidance which offers extensive advice on planning, delivery and assessment as well as exemplar material.
It covers all the Cambridge IGCSE Sciences including Combined, Coordinated and Physical Science.
The guide is available on Teacher Support or a printed version may be ordered through the Publications
Catalogue, accessible via the Cambridge public website www.cie.org.uk. This guide aims to provide material
that will help teachers to deliver the coursework in alignment with the assessment criteria throughout the
duration of the course.
A separate publication called: Coursework Training Handbook (Part 2): Teacher Accreditation is available for
those seeking accreditation. Through the Publications Catalogue which can be found on the Cambridge
website.
Teachers seeking accreditation must work through Part 1 of the Coursework Training Handbook before
attempting the accreditation course (Part 2) which consists of a number of tasks that teachers must work
through and then submit to Cambridge for appraisal.
Teachers are notified (by post) within 4–6 weeks whether they have achieved accreditation status. If
accreditation status is not awarded then the teacher can still continue to teach and mark coursework
though they should not take part in moderating the marking of others. Teachers are free to resubmit their
applications for accreditation any number of times, although each submission will incur a fee.
6.4 Training
Teacher Support also has a list of upcoming training events. These include:
•
on-line courses, including tutor-led courses. The tutor-led courses are highly recommended to help you
improve your teaching skills. They are intended for teachers who have already been teaching IGCSE
Chemistry for one year
•
face-to-face courses, held at various venues at different times throughout the year. These enable
you to meet up with other IGCSE Chemistry teachers, and also to interact directly with a trainer from
Cambridge
•
online seminars, which are led over a short period of time by an expert, and focus on specific issues
such as syllabus changes or the recent examination session.
You can also find information about face-to-face training events at www.cie.org.uk/events
In addition, Cambridge runs professional development courses for teachers who want to develop their
thinking and practice. These include the Cambridge International Certificate for Teachers and Trainers, and
the Cambridge International Diploma for Teachers and Trainers. You can find information about these at
www.cie.org.uk/qualifications/teacher
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Cambridge IGCSE Chemistry 0620
Appendices
Appendices
Appendix A: Teaching syllabus version 1
Appendix B: Teaching syllabus version 2
Appendix C: Sample medium-term plan
Appendix D: Sample lesson plan template
Appendix E: Sample plan for a 70 minute lesson on the order of reactivity
Appendix F: Suggested practical activities
Cambridge IGCSE Chemistry 0620
25
Appendix A: Teaching syllabus version 1
Appendix A: Teaching syllabus version 1
26
Suggested teaching order
Syllabus reference
Particles
Separation
Atoms elements and compounds
Bonding
The Periodic Table
Oxides
Acids bases and salts
Identification of ions and gases
Equations
Calculations
Speed of reaction
Reversible reactions
Reactivity of metals
Properties of metals
Uses of metals
Extraction of metals
Electricity and chemistry
Redox
Carbonates
Sulfur
Fuels
Air and water
Names of compounds
Organic chemistry
1
2.2
3.1
3.2
9
8.2
8.1 + 8.3
8.4
4
4.1
7.1
7.2
10.2 + 6.2 part
10.1
10.3b
10.3a
5
7.3
13
12
14.2 + 6.1 & 6.2 part
11
14.1
14.3-14.8
Cambridge IGCSE Chemistry 0620
Approximate time (weeks)
1
3
2
3
4
1
3
4
2 + parts of other units
2
3
1
4
2
1
3
4
2
1
2
2
5
2
4
}
Appendix B:
Appendix B: Teaching syllabus version 2
Suggested teaching order
Syllabus reference
Air and water
Separation
Earth carbonates
Sulfur
Ores and the extraction of metals
Uses of metals
Petroleum fuels
Organic chemistry
Energy
Speed of reaction
Equilibrium
Particles
Atoms elements and compounds
Bonding
Periodic Table
Redox
Acids, bases and salts
Identification of ions and gases
Equations
Calculations
11
2.2
13
12
10.3
10.3
14.2
14.3-14.8
6.1,6.2
7.1
7.2
1
3.1
3.2
9
7.3
8.1-8.3
8.4
4
4.1
Approximate time (weeks)
5
3
2
2
3
1
2
6
3
3
2
1
3
3
4
2
3
3
2
2
Cambridge IGCSE Chemistry 0620
27
Cambridge IGCSE Chemistry 0620
Ref
Learning Objective
Teaching activities
Resources
10.1
Describe the general
physical and chemical
properties of metals.
Class practical testing the electrical conductivity
of a number of metallic and non-metallic
substances. Demonstration of malleability
versus brittleness of a range of substances.
Electrical circuits with bulbs and clips. Range
of suitable materials. Hammer.
10.1
Explain why metals
are often used in the
form of alloys. Identify
alloys from a structure
diagram.
Sheet or internet activity on nature and
properties of alloys
or
Demonstration of properties of lead, tin and
solder. Solder made to be tested.
Sheets or URL and internet access as
appropriate. Samples of tin and lead +
crucible, etc.
10.2
Place in order K, Na,
Ca, Mg, Zn, Fe, H2 and
Cu by reaction with
water/steam and HCl
Revise properties on Na and K. Class prac:
reactions of the rest with water and acid.
T-ts HCl(aq) samples of metals in the form
of turnings or similar.
10.2
Order of reactivity
of same metals by
displacement with
solutions of salts of
others in the list.
Class practical investigating reaction of strips of
metal in solutions of salts of the same metals +
AgNO3(aq).
Metals (not Ca) as strips or similar solutions
of salts of same metals. Test-tubes for
reactions.
10.2
Reactivity and the
effect of heat on
hydroxides and nitrates
of listed metals.
Demonstration of effect of heat on hydroxides
and nitrates. Explanation of products formed
during demonstration and identification of
products.
NaOH, Ca(OH)2, Mg(OH)2, Zn(OH)2
+ nitrates of Na, K, Mg, Cu.
6.2
Effect of the reactivity
of the electrodes on the
voltage of a simple cell.
Class practical testing the voltage of cells
consisting of different pairs of metals immersed
in aqueous sulfuric acid.
H2SO4(aq) 0.5mol/dm3. Strips of Mg, Zn,
Cu + iron nails. Small beakers, wires and
voltmeters.
Appendix C: Sample medium-term plan
28
Appendix C: Sample medium-term plan
Learning Objective
Teaching activities
Resources
10.2
Reactivity and the
displacement reactions
of metals and the
oxides of other metals.
Demonstration of thermit type reactions of
metals with metal oxides. Reactivity assessed
by vigour of reaction (if any).
Powdered metal and their oxides. Mg, Zn,
Fe, Cu. Metal trays/crucibles for reactions.
10.3a
Describe the ease in
obtaining metals from
their ores by relating
the elements to the
reactivity series.
Class practical extracting copper from copper
oxide by heating with charcoal.
CuO + charcoal. Hard glass test-tubes.
Bunsen burners.
10.3a
Describe the essential
reactions in the
extraction of iron from
hematite.
Class to be divided into groups to ‘research’ one
of the three topics on the left.
Access to computers and internet.
10.3a
10.3a
+5
Describe the
conversion of iron into
steel using basic oxides
and oxygen.
Paper, pens for presentation or access to
PowerPoint.
Groups to present their findings to the whole
class.
Teacher input by questioning to ensure that all
understand each process.
May last two or three lessons depending on the
class.
10.3a
Describe in outline the
extraction of zinc from
zinc blende.
Consolidation of above lessons and extension to
zinc production.
Worksheets.
10.3b
+10.2
Explain the apparent
unreactivity of
aluminium. Name the
uses of aluminium
in aircraft and food
containers.
Class practical investigating reaction of
aluminium with water and acid.
Demonstration showing how chloride ions
increase reactivity.
Explanation of importance of oxide layer
(anodisation).
Aluminium foil, HCl(aq) H2SO4(aq),
CuSO4(aq), CuCl 2(aq), NaCl(aq). Test-tubes.
29
Appendix C: Sample medium-term plan
Cambridge IGCSE Chemistry 0620
Describe in outline
the manufacture of
aluminium from pure
aluminium oxide in
molten cryolite.
Research conducted largely, but perhaps not
entirely using the ‘Alchemy’ programme.
Cambridge IGCSE Chemistry 0620
10.3b
Teaching activities
Resources
Describe the uses of
aluminium and copper
in cooking utensils and
as electrical conductors.
Describe the use of zinc
in galvanising and in
making brass.
Research task. Uses to be investigated are given
to class. They must discover, in groups, why the
particular metal is suited to that task.
Access to books, internet as appropriate,
paper and pens to record groups findings.
Describe changing the
properties of iron by
forming alloys.
Describe the uses of
mild steel and stainless
steel.
Summary sheet available if needed.
Plenary session pooling everyone’s results
to ensure that, in the end, everyone has the
correct answers.
Appendix C: Sample medium-term plan
30
10.3b
+5
Learning Objective
Appendix D: Sample lesson plan template
Appendix D: Sample lesson plan template
Lesson:
School:
Date:
Teacher name:
Class:
Number present:
Absent:
Learning objective(s)
that this lesson is
contributing to
Lesson objectives
Vocabulary,
terminology and
phrases
Previous learning
Plan
Planned
timings
Planned activities
Resources
Beginning
Middle
End
Cambridge IGCSE Chemistry 0620
31
Appendix D: Sample lesson plan template
Additional information
Differentiation – how
do you plan to give
more support? How do
you plan to challenge
the more able learners?
Assessment – how are
you planning to check
learners’ learning?
Health and safety check
ICT links
Reflection and evaluation
Reflection
Were the lesson
objectives realistic?
What did the learners
learn today?
What was the learning
atmosphere like?
Did my planned
differentiation work well?
Did I stick to timings?
What changes did I make
from my plan and why?
Use the space below to reflect on your lesson. Answer the
most relevant questions from the box on the left about your
lesson.
Summary evaluation
What two things went really well (consider both teaching and learning)?
1:
2:
What two things would have improved the lesson (consider both teaching and learning)?
1:
2:
What have I learned from this lesson about the class or individuals that will inform my next
lesson?
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Cambridge IGCSE Chemistry 0620
Appendix E: Sample plan for a 70 minute lesson on the order of reactivity
Appendix E: Sample plan for a 70 minute lesson on the order of
reactivity
Lesson:
School:
Date:
Teacher name:
Class:
Number present:
Absent:
Learning objective(s)
that this lesson is
contributing to 10.2
Reactivity Series
•
Place in order of reactivity: potassium, sodium,
calcium, magnesium, zinc, iron, (hydrogen) and
copper, by reference to the reactions, if any, of the
metals with
– water or steam
– dilute hydrochloric acid.
Lesson objectives
By practical means, class practical and demonstration to confirm the
order of reactivity of the metals provided.
Vocabulary,
terminology and
phrases
Reactivity = how quickly a metal reacts with a substance relative to
other metals.
Previous learning
They know that alkali metals react with water to produce hydrogen.
Plan
Planned
timings
Planned activities (replace the notes
below with your planned activities)
Resources
Beginning
7 minutes
Class watch brief video of the reaction of
alkali metals with water. Each learner has
a sheet to fill in the three metals observed
in order of how rapidly they react, most
reactive first. The sheet also has spaces for
the other metals to be tested.
Video, data projector and
screen.
Printed sheet to record
answers
Middle
5 minutes
10 minutes
Instructions to class including safety issues.
10 minutes
React each of samples of metal turnings
with hot (not boiling) water. Record results.
For class practical. Test-tube
racks and test-tubes. Access to
water and a supply of
1 mol/dm3 hydrochloric acid.
Bunsen burner. Ca, Mg, Zn, Fe
and Cu turnings.
10 minutes
React each of metals with dilute
hydrochloric acid. Record results.
10 minutes
Tidy up and put away apparatus.
10 minutes
Demo of reaction of metals with steam.
React each of samples of metal turnings
with cold water. Record results.
For demonstration: boiling tube
with mineral wool and stopper
with glass tube.
Cambridge IGCSE Chemistry 0620
33
Appendix E: Sample plan for a 70 minute lesson on the order of reactivity
End
5 minutes
Each learner has filled in the remainder of
the sheet provided at the start. Answers are
checked.
Slide on data projector of work
sheet so that correct answers
can be revealed.
Two further metals have their properties
described, learners have to decide where
they would fit in their list.
Second slide detailing reaction,
with water and hydrochloric
acid, of aluminium and lead.
Additional information
Differentiation – how
do you plan to give
more support? How do
you plan to challenge
the more able learners?
Assessment – how are
you planning to check
learners’ learning?
Health and safety check
ICT links
Practical task accessible
to all. Sheet for record of
conclusions adapted for
those who need it.
Answers on sheets +
correct positions for
additional elements for
more able.
Warning needed on heating water
in test-tubes. Goggles to be worn
whilst using acid.
Reflection and evaluation
Reflection
Were the lesson
objectives realistic?
What did the learners
learn today?
What was the learning
atmosphere like?
Did my planned
differentiation work well?
Did I stick to timings?
What changes did I make
from my plan and why?
Use the space below to reflect on your lesson. Answer the
most relevant questions from the box on the left about your
lesson.
The objectives were realistic because nearly all the class filled in
the sheet correctly. I will see if they really learned next lesson when
there will be a check.
The lesson was rather noisy but most were on task. No-one needed
the extra sheet so differentiation wasn’t needed.
The timings were mostly OK but there wasn’t really time for the last
activity because the demonstration lasted a bit too long.
Summary evaluation
What two things went really well (consider both teaching and learning)?
1: They enjoyed the video and were keen to start their practical.
2: They enjoyed ‘popping’ the hydrogen.
What two things would have improved the lesson (consider both teaching and learning)?
1: The demonstration wasn’t as good as it could have been. Class wasn’t involved.
2: Assessment task at the end was too easy for the more able. Most got it right.
What have I learned from this lesson about the class or individuals that will inform my next
lesson?
A few students were not as sensible as they should have been with acid. They need a warning before
next time.
34
Cambridge IGCSE Chemistry 0620
Appendix F: Suggested practical activities
Appendix F: Suggested practical activities
Section 1
Diffusion
In liquids spread of blue from a copper sulfate crystal at the bottom of water.
In gases the spread of a smell (nice or nasty) around a room.
Quantitatively HCl and NH3 gas (from their solutions) in a closed tube.
Section 2
Purity
Chromatography of inks or the colours of sweets.
Temperature of ice and water and of boiling salt water (draw a graph).
Cooling curves for octadecenol and wax.
Purification
Filtration and crystallisation (purification of rock salt).
Distillation of ink, or salt water.
Fractional distillation of petroleum (use artificial) or ethanol water.
Section 3
Elements mixture
and compounds
Heat iron filings and sulfur. Try to separate before and after.
Dutch metal (copper) and chlorine gas. Alloys – react brass with
hydrochloric acid leaving the copper behind.
Bonding
Show differences in M.P. solubility and electrical conduction of different
substances.
SiO2, NaCl, Wax, I2, Zn, Pb, CuSO4, etc.
Section 4
Stoichiometry
Formula of magnesium oxide by weighing and heating magnesium in air.
Reduction of copper oxide with methane weighing before and after.
The Mole
Many examples, e.g. titrations of simple acids and bases. Mg + H2SO4 measure the
hydrogen produced and evaporate the magnesium sulfate to dryness. The numbers
work well.
Section 5
Electrolysis
There are many examples listed in the syllabus.
Getting energy from two metals immersed in acid (simple cell) links with section 6.
Section 6
Chemical changes
Reacting sodium carbonate and sodium hydrogen carbonate separately with HCl.
Comparing two fuels by using them in spirit burners to heat water.
Cambridge IGCSE Chemistry 0620
35
Appendix F: Suggested practical activities
Section 7
Rate Concentration
The reaction between sodium thiosulfate and hydrochloric acid. Colour change.
The reaction of magnesium or marble with hydrochloric acid.
Collect the gas.
Rate temperature
Same reaction as above can be used.
Rate particle size
Limestone pieces and acid are easiest to do (use weight loss on a balance).
Rate catalyst
MnO2, CuO and Charcoal as ‘catalysts’ for decomposition of hydrogen peroxide.
Rate light
Change of colour of freshly precipitated silver chloride in different light conditions.
Reversible reactions Heating hydrated copper sulfate and, after cooling, adding water.
Redox
Reacting a powdered metal with KMnO4.
Reacting H2O2 with potassium iodide solution.
Section 8
Properties of acids
and bases
Testing solutions with UVI and/or other indicators.
Reaction of acids with metals and carbonates.
Neutralisation reactions (titrations).
Types of oxides
Burning elements in oxygen or air, dissolving oxide in water and testing with UVI.
Making salts
Acid + excess metal, acid + excess oxide, acid + excess carbonate in all cases
followed by filtration and evaporation to crystallisation point.
Insoluble salts by precipitation, followed by filtration washing and drying.
Identification of ions Using tests in syllabus.
and gases
Using tests, once practised, to identify unknown compounds.
Section 9
36
Group properties
Reaction of Group 1 metals with water.
Reaction of solutions of halogens with solutions of halide salts to show reactivity.
Reactions of halogens with iron wool.
Transition metals
Compare a range of transition metals and their compounds with other metals to
show colour and variable oxidation, cf. Redox.
Cambridge IGCSE Chemistry 0620
Appendix F: Suggested practical activities
Section 10
Reactivity Series
Heat powdered metals to see reaction with air/oxygen.
Reaction of metals with water and with dilute acid.
Displacement reaction of metals in solutions of metal salts.
Displacement reactions (thermit) heating powdered metals with metal oxides.
Extraction of Metals Heating copper oxide with carbon to produce copper.
Production of copper by electrolysis of copper sulfate solution.
Section 11
Composition of
the air
Using gas syringes to pass air over hot copper.
Bubbling air through lime-water using a filter pump.
Rusting
Investigate conditions necessary for rusting.
Investigate the effect of very dilute acid and of salt on rate of rusting.
Investigate the effect of grease, paint, and a more reactive metal.
Sections 12 and 13
Limestone
Strongly heat a piece of limestone to form lime, allow to cool and then add water.
Section 14
Fuels
Burn fuels and test to show products are carbon dioxide and water.
Fractional distillation of petroleum to compare properties of the fractions.
Alkanes and alkenes Compare the flames from alkanes and alkenes.
Test alkanes and alkenes with bromine water.
Alcohols and acids
Burn ethanol compare flame with hydrocarbons.
Warm a mixture of acid and alcohol with conc. sulfuric acid pour into water and
smell.
Macromolecules
Make nylon66 from diaminohexane and adipyl chloride.
Hydrolyse starch to sugar.
Ferment carbohydrate to make alcohol.
Cambridge IGCSE Chemistry 0620
37
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