g-study and revision skills--igcse chemistry scool cd

1Study and revision skills© Cambridge University Press IGCSE Chemistry

Study and revision skills

General study methods

Organisation of study timeTh e examinations are looming large. Suddenly you realise that you do need your notes and experimental work from the last year or two. Are they in good shape? Well...!

It is worth remembering that revision is just that. It shouldn’t be the fi rst time that you have tried to get to grips with a subject. Organisation of study habits over a whole course is a vital part of being successful. Th is certainly means practical things, such as making sure that your notes are intact and readable. But it also includes making sure that you have understood the ideas and connections as you have covered a topic. Nothing can be worse than trying to learn masses of material that you don’t understand. Th e best preparation for an examination begins a long time before it! Th is spreads the load and lessens the tension as the examination approaches.

Figure 1 summarises various aspects of preparing for examinations. Th e coursework ‘arm’ emphasises not only the collection of good notes directly from class, but also the need to look at and use material from outside.

Reading reference material and taking useful notes from it is a skill in itself. Table 1 outlines diff erent methods of reading and their purpose. Th e fi rst three methods are more appropriate to using books for reference. However, there is an increasing number of popular science books and magazines for which the last two methods are appropriate. In addition, there is an increasing amount of reference material now available on CD-ROM and, most signifi cantly, the internet. You should fi nd ways of using this material, as it provides a more interactive presentation of the material.

Th e ability to make notes and topic summaries as you work through a course is important, as they can then be used as a starting point for revision. You should not think of practical work in chemistry as separate from other classwork. Th e ideas and detailed information from the practicals are important in reinforcing your understanding of a topic. Indeed, a particular experiment may help you to remember and understand a crucial idea – giving you a visual clue on which to ‘hang’ the idea in your memory.

INFO

This section covers the following ideas and material:

An introduction to revision methods, including

• concept mapping, fl ow charts and mind maps

• planned revision timing

• practising examination technique.

2 Study and revision skills© Cambridge University Press IGCSE Chemistry

Th is book, and the accompanying materials, are aimed specifi cally at students taking the Cambridge IGCSE Chemistry course. Th is is a course and qualifi cation with a very high international reputation.

Table 1 Different methods of reading and their purpose.Table 1 Different methods of reading and their purpose.

Type of reading Method Purpose

skimming looking for the main topics to gain an overall impression

scanning looking for specifi c information to fi nd particular facts or conclusions

refl ective reading reading carefully and thoughtfully, with attention to detail

to obtain a thorough understanding of a topic

detecting bias separating fact from opinion to form a decided impression of a controversial area

reading for pleasure reading at own pace to gain a feel for a subject, and for enjoyment

Figure 1 Revision involves organisation and the development of particular skills.

REVISIONSKILLS

COURSEWORK

reading

CD-ROM

practical work

classnotes

review cards summary sheets

spider diagrams

topic lists

mind maps

how much? when?

take breaks

use a timetable

stick to timetable

suitable place

time of day

alone or witha friend

key words and ideas

regular reviews

use summaries, spiderdiagrams and mind maps

Info

rmat

ion

Organising notesOrganisin

g time

Memory

skills

Study habits


Getting startedWe have said it earlier, and it can be boring to repeat it, but it remains true all the same: to make sure of a high grade in your fi nal examinations you will need to work hard throughout your course. Here are some tips to help you make the best use of the time you put in on your work in chemistry.

Make sure you have a copy of the IGCSE Chemistry syllabus. Th ere is one provided on this CD which also gives you guidance as to where in the book the diff erent topics are covered. It is important you know the course you are taking and the way in which you will be assessed.

IGCSE exams aren’t just about learning facts. You need to be able to understand your work and become suffi ciently confi dent in your understanding to answer questions about things you have never met before. You need to be able to transfer your knowledge in a particular area to an example that will be unfamiliar to you.

Th e IGCSE examiners will be setting questions to test three sets of skills (they are known as Assessment Objectives). Th ese are:• Skill A: knowledge with understanding• Skill B: handling information and solving problems• Skill C: experimental skills and investigations.About 50% of all the marks in the exam are for skill A, 30% for skill B and 20% for skill C.Skill A is about learning and understanding all the facts and concepts in the syllabus. Th ese are covered in your textbook, and your teacher will make sure you have met them all in class as your course progresses. Th ere are no craft y shortcuts, it is simply a case of getting your head down and working at these.

Skill B is about using these facts and concepts and applying them to an unfamiliar context. It’s important that you become confi dent in tackling questions that, at fi rst sight, look completely new. Th e workbook will give you lots of practice at this. Trying past question papers will also help to test this skill, but there will still be unusual material that you will meet for the fi rst time in the exam. Th e following ‘model exam question’ is similar to the type of question found on an extended paper and will give you some idea of what to expect. Cathodic protection of steel objects is not mentioned in the syllabus whereas sacrifi cial protection is. Yet here you are asked to compare the two using your knowledge and understanding of electrolysis.

Skill C is about practical skills. You should have plenty of opportunity to do experiments in a laboratory throughout your course. Th e workbook also has exercises that will help you to improve your skills at handling and interpreting data obtained from experiments, and designing experiments. But make sure you gain the most you can from your practical sessions. Chapter 12 gives you clear guidance about what is involved in the assessment of your practical work.

INFO

There is an excellent website for Cambridge IGCSE students, at:

www.cambridgestudents.org.uk/subjectpages/chemistry/igcsechemistry

Do take a good look at this website. You will fi nd copies of past papers, model answers to

past questions, some simulations, and revision checklists based on the syllabus. The tips from

examiners are there to help you do well in the exam and are certainly worth taking note of.

The website is worth visiting regularly, as new material and up-to-date papers are added to it.


Model QuestionsQ

For relevant material, see Chapter 9.

Titanium is very resistant to corrosion. One of its uses is as an electrode in the cathodic protection of large steel structures from rusting.

a Defi ne oxidation and reduction in terms of electron transfer. [2]Oxidation is the loss of electrons Reduction is the gain of electrons

HINT: Remember OIL RIG – to help remember ‘oxidation is loss; reduction is gain’

b Th e steel oil rig is the negative electrode (cathode) in this protective electrolytic arrangement. Name the gas formed at this electrode. [1]Hydrogen

HINT: Discharge of H+ ions from the seawater.

c Name one of the two possible gases formed at the titanium anode. [1]Oxygen (or chlorine)

HINT: Discharge of OH− ions or Cl− from the seawater.

d Explain why the oil rig does not rust. [2]The oil rig legs are the cathode in the cell that is set up (see diagram)-

and oxidation does not take place at the cathode (electrons are moving

towards the cathode, not away from it).

HINT: See Chapter 4 – oxidation takes place at the anode in electrolysis; reduction

takes place at the cathode. Do not confuse this with sacrifi cial protection.

e Another way of protecting steel from corrosion that involves using another metal is sacrifi cial protection.Give two diff erences between sacrifi cial protection and cathodic protection. [2]Cathodic protection involves electrolysis and needs electricity; it uses an

inert electrode (here made of titanium).

Sacrifi cial protection needs a more reactive metal; this metal corrodes

instead of the steel.

Sacrifi cial protection does not need electricity.

f What is the name of the method of rust protection that uses zinc? [1]Galvanisation

steel oil rigwhich is cathode

power+ –

titaniumanode

seawater containsH+(aq), OH–(aq),Na+(aq), Cl–(aq)


Keeping up progressDuring the course you will be given work to do. Try to work steadily through all the necessary material throughout your course. It is really important that you keep up with this. Don’t set out to make life diffi cult for yourself. Do make sure that you understand each piece of work you do. Research shows that we fi nd it much easier to learn and remember things if we understand them. If there is something you don’t understand, make sure you do everything you can to put this right straight away. Quite oft en working through a topic with a friend will help. Use your school library or the internet. Be careful of the internet, though, as many chemistry sites are written for other courses in diff erent countries. Th ese can use diff erent approaches and it is diffi cult to apply the explanations you see. Ask your teacher for a (short) list of reliable sites you can go to regularly.

Strategies of studyYour study sessions should use a variety of techniques to aid your understanding and learning of the material. Simply reading over your notes is not a particularly productive strategy. Try to summarise topics as you read, then shorten the summary down to a set of key words. Having learnt these, try to reconstruct notes on the topic. Your learning and understanding can also be checked and developed by answering questions from past examination papers. Keep the length of time taken to answer questions in mind when testing yourself. Th ere is no point in preparing over-elaborate answers to short questions.

An important aspect of understanding a topic is to ‘see the connections’ between the ideas involved. Establishing these links makes it so much easier to remember the details of a topic. Pictorial methods of linking ideas can be very useful for this.

INFO

The methods available include:

• fl ow charts

• concept maps

• Venn diagrams

• mind maps.

Th e importance of all these methods is that they force us to sort out the material into key ideas, and then to establish the links between them. It is useful to draw up the diagrams for yourself. Remember that your ‘maps’ may well diff er from other people’s. Comparing notes with others, or even drawing them up together as a group, can also be very useful. Sharing ideas and comparing maps helps you to think things through. As you use these methods, you will develop greater skill in drawing them up.

Flow charts are linear in their approach and work down from a major idea by a series of subdivisions. Th ey are useful for emphasising the diff erent types of chemical substance, for example (see examples of charts in Chapters 2 and 3 in the textbook). Concept maps and mind maps are particularly useful for helping you to see the fl ow of ideas. In a concept map (Figure 2), the interlinking idea is written alongside the connecting arrow.


Venn diagrams are useful for showing where diff erent categories overlap. For example, the diff erent ways in which we categorise reactions can result in overlaps. Figure 3 shows this. It also shows how the term ‘redox reaction’ covers a wide range of reactions.

Figure 2 a Spider diagrams, and b concept maps involve organising ideas and their connections.

a combustionneutralisationprecipitation

synthesisredox

a word or symbolequation

a catalystspeedsup a

are types of

can be written down as

example: zinc + oxygen → zinc oxide 2Zn + O2 → 2ZnO

these areelements

this is acompound

this means2 atoms of zinc

this means1 molecule of oxygen

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equation

chemical reaction

bELECTROLYSIS

ELECTRONS

OXYGEN

REDOXREDUCTION OXIDATION

COMBUSTIONBLAST FURNACE

is the processthat positive

ions undergo atthe cathode

during

is the processthat negative

ions undergo atthe anode

duringis theloss of

is thegain of

is the opposite process to

is the opposite process to

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is theremoval of

element removed from metal ores by carbon in reactions in which substances react with

process usedto extractmetals in

the

is a specialform of

transferredduring


NEUTRALISATION

acid + base/alkali →salt + water ONLY

PRECIPITATION

forming an insolublesolid by a chemical

reaction

REDOXSynthesis

Decompositionto elements

Displacement

Electrolysis

sodium thiosulfate +hydrochloric acid

Figure 3 A Venn diagram showing various types of reaction. Can you think of examples to fi ll each space? (One has been done for you.)

Figure 4 shows a mind map covering aspects of the nature of atoms and molecules. Th is particular map covers a wide range of ideas – radiating from the central idea that matter is made up of very small particles (atoms or molecules, depending on the substance being talked about). Th e interconnections of ideas are emphasised. Putting the map on paper helps you to sort out your ideas! Th ere are obviously overlaps between diff erent topics. Th ere are various pieces of mind-mapping soft ware available (one was used to construct Figure 4) and you can fi nd these on the internet.

However, it is important not to get over-involved in the processes of a particular IT package. In many ways the important thing about ‘mind-mapping’ is that it can be practised quite casually, and frequently, simply on a piece of ‘rough’ paper. Sketching diff erent ‘mind maps’ on diff erent topics is a way of looking at the subject from diff erent angles to aid the memory. Th e main point is the thinking that is done while constructing the ‘map’.


Figure 4 A mind map on ‘atoms and molecules’.

describes the statesof matter and the

movement of particlesin these states

the particles inmatter are moving

all the time

all matteris made

up of very smallparticles

much slower inliquids than gases

heavier particles movemore slowly than lighter

particles at the sametemperature

does not takeplace in solids

the higher thetemperature, the

higher the averageenergy of the particles

different substances containdifferent types of particles, e.g.

atoms, ions or molecules

Kinetictheory

definition

Diffusion

atoms of differentelements can combineto make the molecules

of a compound

a pure element containsonly atoms with the samenumber of protons in the

nucleus

atoms of anelement areeach given

their own symbol

the atoms of thedifferent elements

differ in size

atoms are thesmallest particlesthat take part in achemical reaction

ATOMS AND

MOLECULES

Atomictheory

no new chemicalsubstances made

easily reversible,e.g. by cooling or

evaporating

e.g. meltingor dissolving

new chemicalsubstances formed

usually noteasily reversible

often energygiven out

various types, e.g.synthesis and

decomposition

Chemicalreactions

Physicalchanges Dalton’s idea


Figure 5 The different ‘storylines’ behind the maps branch into each other.

physical propertiesdepend on how theatoms are linkedtogether

substances

have physical

properties

everything is madefrom about 100elements, each madeup of different atoms

(isotopes) (nucleus)

(atoms can be subdivided)

(nuclear reactions)

(balanced equations)

chemical combinationsof substances havedifferent properties

everything can bemade from a fewsubstances combinedin different ways

everything is madeof invisibly small atoms, linked togetherin different patterns

amount of matter staysthe same (by atomcount) during chemicalchanges

visible objectsmay be made oflarge numbers ofvery smallinvisible particles

structures weighthe same as thetotal mass oftheir parts

the total amount ofmatter stays the same(by mass) duringchemical changes

small parts can beput together indifferent ways tomake differentthings

water evaporatesinto the air

magnifiers andmicroscopes oftenshow that objectsare made ofsmaller parts all materials

come fromsomewhereand must gosomewhere

PROPERTIES OFSUBSTANCES

COMMON ELEMENTS ATOMS ARE INVISIBLYSMALL

CONSERVATION OFMATTER

KEY

Scientificideas

More generalnotions Storylines

Figure 5 shows how several ‘storylines’ can be linked together. Th is type of diagram can help you see the overall pattern of a section of the course you are taking and begin to see the ‘connections’ between ideas. Th e more connections, or associations, you can make between ideas, the more likely you are to understand and remember them.

When a particular part of a course, or a particular topic, is fi nished it can be useful to produce a diagrammatic summary. Th is helps reinforce the linked ideas while they are still fresh in your mind. Th e charts can provide a useful ‘checklist’ when it comes to revision. Th e next three charts (Figure 6a,b,c) show how parts of a course can be summarised. Figure 6a summarises a great deal of the material covered in Chapters 2 and 3, and Figures 6b and 6c fl ow into each other and show how much of chemistry develops from a consideration of the Earth’s resources. Th is ‘map’ of chemistry provides a context for your studies.


PARTICLES

ATOMSMOLECULESIONS

Reaction with WaterStorageVariation down groupDensitym.p.

LIQUIDS

GASES

SOLIDS

a

proton number Z –

PROTONS

ELECTRONS

ORBITS (2,8,8)

PROTONS +NEUTRONS

NEUTRONS = A–Z

p+1

no1

e–1

1840

ATOMIC STRUCTURE

FORMING IONS

CHEMICALBONDS

SHARINGELECTRONS

BASICOXIDES

ACIDICOXIDES

EQUATIONS andCALCULATIONS

Reaction with ironDisplacementColourVariation down groupm.p.

TRANSITION METALS

NOBLE GASESNo reactionsColoured lights

METALS NON-METALS

REACTIVITYOF

METALS

BURNINGIN

AIR and OXYGEN

PHYSICALPROPERTIES

Data Book

FORMULAE

CHEMISTRY SECTION ONE

mass number A

GROUP 1THE ALKALI METALS

GROUP 7THE HALOGENS

Metals lose electronsNon-metalsgain electrons

Coloured compoundsCatalystsHigh m.p.s

IONICCOVALENT

BalancingMr from Ar + %Quantities fromequationsSolids and gasesFormulae from %

BrittlePoor conductorsLow m.p.Dull

PHYSICALPROPERTIES

MalleableConductorsStrongHigh m.p.ShinyAlloys

Figure 6 a, b, c Flow charts can show very clearly the links between different areas of chemistry and help provide an overall pattern to a course.


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The glossary – words are importantChemistry can be said to have a language of its own. As for the other sciences, there are special terms that need to be understood and remembered – an ‘atom’ is not the same thing as an ‘ion’ or a ‘molecule’. Th ere are also some words that have a diff erent slant on their meaning in chemistry. For example, saying that ethanol is ‘volatile’ does not mean that it is about to ‘freak out’, simply that it evaporates easily.

Th roughout the textbook, you will fi nd words that have been highlighted in red bold type. It would be useful to make a note of these and make sure that you are clear about their meaning. A glossary of these important chemical terms is also provided at the end of the book. Th e same glossary is also provided on this CD. If your fi rst language is not English – and possibly even if it is – it would be useful to keep your own ‘chemical vocabulary’ book to help you to learn and understand the terms used in this subject. Th is should help you to understand questions clearly and not get tied up in confusing ‘waffl e’ in your answers.

g-study and revision skills--igcse chemistry scool cd

Documents

revision methods

th e fi

reading reference material

th e ideas

different methods of

th e ability

masses of material

th e best preparation