The Cambridge IGCSE® Combined and Co-ordinated Sciences series is tailored to the 0653 and 0654 syllabuses for first exa
180 119 160MB
English Pages 152 [683] Year 2017
Cambridge IGCSE Combined and Co-ordinated Sciences
B13 Variation and selection
157
..
266
Bl3.0l Variation
157
CS.01 What is an acid?
Bl3.02 Selection
160
CS.02 Acid and alkali solutions
270
CS.03 Metal oxides and non-metal oxides
271
CS.04 Acid reactions in everyday life
273
CS.OS Alkalis and bases
275
CS.06 Characteristic reactions of acids
276
CS.07 Acids and alkalis in chemical analysis
279
CS.08 Salts
280
CS.09 Preparing soluble salts
281
CS.10 Choosing a method of salt preparation
283
B14 Organisms and their environment
167
Bl4.0l Ecology
167
Bl4.02 Energy flow
168
Bl4.03 The carbon cycle
170
Bl4.04 Human influences on ecosystems
171
Chemistry Cl Planet Earth
'■
CS Acids, bases and salts
177
Cl.01 The atmosphere
177
Cl.02 Water treatment
182
Cl.03 The Earth's crust
184
C2 The nature of matter
187
C2.0l The states of matter
CG Quantitative chemistry
266
288
C6.0l Chemical analysis and formulae
288
C6.02 The mole and chemical formulae
295
C6.03 The mole and chemical equations
297
C6.04 Calculations involving gases
299
188
C6.05 Moles and solution chemistry
300
C2.02 Separating and purifying substances
193
C2.03 Atoms and molecules
198
C7 How far? How fast?
306
C2.04 The structure of the atom
203
C7.0l Energy changes in chemical reactions
306
C2.05 Electron arrangements in atoms
207
C7.02 Rates of reaction
311
C3 Elements and compounds
214
C7.03 Catalysts
316
C7.04 Reversible reactions
320
C3.0l The Periodic Table - classifying the elements
215
C3.02 Trends in groups
219
CB Patterns and properties of metals
C3.03 Trends across a period C3.04 Chemical bonding in elements and compounds
222
224
C3.05 The chemical formulae of elements and compounds
232
C3.06 Metals, alloys and crystals
235
C4 Chemical reactions
244
328
C8.0l The alkali metals
328
C8.02 Aluminium
331
C8.03 The transition elements
332
C8.04 The reactivity of metals
334
C9 Industrial inorganic chemistry
343
C9.0l The extraction of metals by carbon reduction
344
C9.02 The extraction of metals by electrolysis
348
C9.03 Ammonia and fertilisers
350
C9.04 Sulfur and sulfuric acid
352
C9.05 The chlor-alkali industry
353
C4.0l Chemical reactions and equations
244
C4.02 Equations for chemical reactions
246
C4.03 Types of chemical reaction
248
C4.04 A closer look at reactions, particularly redox reactions
252
C9.06 Limestone
354
C4.05 Electrolysis
254
C9.07 Recycling metals
355
Contents
Cl0 Organic chemistry
360
P3.03 Mass, weight and gravity
433 435
Cl0.01 The unique properties of carbon
360
P3.04 Force, mass and acceleration
Cl0.02 Alkanes
362
Cl0.03 Alkenes
364
P4 Turning effects of forces
Cl0.04 Hydrocarbon structure
366
Cl0.05 Chemical reactions of the alkanes
366
Cl0.06 Chemical reactions of the alkenes
367
Cl0.07 Alcohols
367
Cl0.08 The reactions of ethanol
370
Cll Petrochemicals and polymers
373
Cll.Dl Petroleum
373
Cll.02 Alternative fuels and energy sources
379
Cll.03 Addition polymerisation
380
Cll.04 Condensation polymerisation
382
C12 Chemical analysis and investigation
388
Cl2.0l Chemical analysis
388
Cl2.02 Inorganic analysis
389
Cl2.03 Organic analysis
394
Cl2.04 Experimental design and investigation
395
Cl2.05 Practical skills
398
Physics
441
P4.0l Keeping upright
441
P4.02 The moment of a force
441
P4.03 Calculating moments
444
P4.04 Stability and centre of mass
446
PS Forces and matter
451
P5.0l Forces acting on solids
451
P5.02 Stretching springs
452
P5.03 Hooke's law
454
P5.04 Pressure
455
PG Energy transformations and energy transfers
462
P6.0l Energy for life
462
P6.02 Forms of energy
463
P6.03 Energy conversions
465
P6.04 Conservation of energy
466
P6.05 Energy calculations
469
P7 Energy resources
476
P7.0l The energy we use
476
P7.02 Energy from the Sun
480
Pl Making measurements
403
Pl.01 How measurement improves
403
PS Work and power
484
Pl.02 Measuring length
404
P8.0l Doing work
484
Pl.03 Density
406
P8.02 Calculating work done
485
f 1.04 Measuring time
409
P8.03 Power
488
P2 Describing motion
414
P8.04 Calculating power
489
I 2.01 Understanding speed
414
P9 The kinetic model of matter
494
I 2.02 Distance-time graphs
419
P9.0l States of matter
494
I 2.03 Understanding acceleration
419
P9.02 The kinetic model of matter
496
I i2.04 Calculating speed and acceleration
422
P9.03 Forces and the kinetic theory
499
P3 Forces and motion
430
P9.04 Gases and the kinetic theory
501
I .01 Roller-coaster forces
430
PIO Thermal properties of matter
,, .02 We have lift-off
430
Pl0.01 Thermal expansion
506 506
■
Cambridge IGCSE Combined and Co-ordinated Sciences
509
P18 Electrical quantities
Pl0.03 Designing a thermometer
5ll
Pl8.0l Current in electric circuits
596
Pl8.02 Electrical resistance
600
Pll Thermal (heat) energy transfers
I
516
Pll.01 Conduction
516
Pll.02 Convection
519
Pll.03 Radiation
521
Pll.04 Some consequences of thermal (heat) energy transfer
523
P12 Sound
530
Pl2.0l Making sounds
530
Pl2.02 At the speed of sound
532
Pl2.03 Seeing sounds
534
Pl2.04 How sounds travel
536
P13 Light
Ill
•
Pl0.02 Temperature and temperature scales
541
Pl3.0l How far to the Moon?
541
Pl3.02 Reflecting light
542
Pl3.03 Refraction of light
546
Pl3.04 Total internal reflection
550
Pl3.05 Lenses
552
P14 Properties of waves
561
Pl4.0l All at sea!
561
Pl4.02 Describing waves
562
Pl4.03 Speed, frequency and wavelength
566
Pl4.04 Explaining wave phenomena
567
P15 Spectra
575
Pl5.0l Infrared, ultraviolet
575
Pl5.02 Electromagnetic waves
57 7
P16 Magnetism
581
Pl6.0l Permanent magnets
581
Pl6.02 Magnetic fields
583
P17 Electric charge
589
P17.0l A bright spark
589
Pl7.02 Charging and discharging
590
Pl7.03 Explaining static electricity
591
596
Pl8.03 More about electrical resistance
602
Pl8.04 Electricity and energy
604
P19 Electric circuits
609
Pl9.0l An international language
609
Pl9.02 Circuit components
609
Pl9.03 Combinations of resistors
613
Pl9.04 Electrical safety
616
P20 Electromagnetic forces
621
P20.0l Electricity meets magnetism
621
P20.02 The magnetic effect of a current
622
P20.03 Force on a current-carrying conductor
625
P21 Electromagnetic induction
630
P21.0l Generating electricity
630
P21.02 Power lines and transformers
633
P22 Atomic physics
641
P22.0l Atomic structure
641
P22.02 Radioactivity all around
645
P22.03 The microscopic picture
647
P22.04 Radioactive decay
651
P22.05 Using radioisotopes
653
Glossary
660
Index
663
CD-Rom Revision checklists Multiple-·choice tests Glossary (matches the coursebook) Notes on activities for teachers/technicians Self-assessment checklists Activities Answers to end-of-chapter questions Answers to questions Study and revision skills Helps notes and terms and conditions
Thanks to the following for permission to reproduce images:
Cover image: Pery Burge/Science Photo Library Biology
Bl unit opener, Bl.OS JOHN DURHAM/SPL; Bl.01, Bl.02, 4.01, BS unit opener, BS.07 Eleanor Jones; Bl.03, B8.03 BIOPHOTO ASSOCIATES/SPL; Bl.04, B2 unit opener, B2.0l, BS.01-5.04, B9.0l, Bl0.03, Bl3 unit opener, Bl3.0l, Bl3.05a, Bl4 unit opener, Bl4.02, Bl4.03 Geoff Jones; B3 unit opener, B3.03 Top-Pies TBK/Alamy Stock Photo; B3.0l MARTYN F. CHILLMAID/SPL; B3.02. B3.04, B3.05 ANDREW LAMBERT PHOTOGRAPHY/SPL; B4 unit opener, B4.04 Nigel Cattlin/Alamy Stock Photo; B4.02, B6 unit opener, 6.03 DR KEITH WHEELER/SPL; B4.03, B6.0l, Bl2.0l POWER AND SYRED/SPL; BS.OS Alex Segre/Alamy Stock Photo; BS.06 Images of Africa Photobank/Alamy Stock Photo; B6.02, Bll unit opener, Bll.01 STEVE GSCHMEISSNER/SPL; B7 unit opener, B7.02 PHOTOTAKE lnc./Alamy Stock Photo; B7.0l PROF. P. MOTTA/DEPT. OF ANATOMY/UNIVERSITY "LA SAPIENZA", ROME/SPL; B8 unit opener, B8.02 Tom Merton/Caiaimage/Getty Images; B8.0l PETER MENZEL/ SPL; B8.04 CORBIN O'GRADY STUDIO/SPL; B9 unit opener Science Photo Library - KTSDESIGN/Getty Images; BlO unit opener, Bl0.05 Pictox/Alamy Stock Photo; Bl0.01 SCIENCE PICTURES LIMITED/SPL; Bl0.02 IRENE WINDRIDGE/SPL; Bl0.04 Mediscan/Alamy Stock Photo; Bl0.06 DAVID M. PHILLIPS/SPL; Bl2 unit opener, B12.05, B13.02a imageBROKER/Alamy Stock Photo; B12.02 CNRI/SPL; B12.03 LEONARD LESSIN/FBPA/SPL; Bl2.04, Bl4.04 blickwinkel/Alamy Stock Photo; Bl3.02b Sam Sangster/Alamy Stock Photo; Bl3.03 Mary Evans Picture Library/Alamy Stock Photo; Bl3.04 PAT & TOM LEESON/SPL; Bl3.05b Terry Mathews/Alamy Stock Photo; Bl4.0l Richard Wareham Fotografie/Alamy Stock Photo; Bl4.05 Robert Brook/Alamy Stock Photo Chemistry
Cl unit opener, Cl.01 ESA/KEVIN A HORGAN/SPL; Cl.02, fig. C5.02b Leslie Garland Picture Library; Cl.03 joebelanger/iStock/Getty Images Plus/Getty Images; C2 unit opener, C2.08 PEKKA PARVIAINEN/SPL; C2.02, C2.03, C2.04, C2.06, C2.07, C3.03, C3.04, C3.07b, C4.0l, C4.05-7, C4.08a(i),a(ii),b, CS unit opener, Fig CS.02, Fig C5.6b, Fig C5.09b, C7.06, C7.10, Cl0.03, Cl2 unit opener, Cl2.02a,b, Cl2.03 ANDREW LAMBERT PHOTOGRAPHY/SPL; C2.05 Courtesy of IBM Archives; C2.0l, C4 unit opener, C4.03 CHARLES D. WINTERS/ SPL; C3 unit opener, C3.08 KENNETH LIBBRECHT/SPL; C3.0l, C3.05, C8.07, C8.09, Cl0.01, Cl2.0l Richard Harwood; C3.02 Kerstin Waurick/iStock/Getty Images Plus/Getty Images; C3.06, C3.07a, C4.02 MARTYN F. CHILLMAID/SPL; C4.04a,b, C4.09, CS.03 TREVOR CLIFFORD PHOTOGRAPHY/SPL CS.01 DAVID MUNNS/SPL CS.04 EUROPEAN SPACE AGENCY/AEOS MEDIALAB/SPL CS.OS Jeremy Pardoe/Alamy Stock Photo; CS.06, C9.09a MARTIN BOND/SPL; C5.07a, CS.08, C7.04, C7.07, (7.09, C9.04, Cl0.02 MARTYN F. CHILLMAID/SPL; C5.07b, C7 unit opener, C7.05, C8.0l, C8.10a,b, Cll.06b CHARLES D. WINTERS/SPL; CS (tip) ARNOLD FISHER/ SPL; C6 unit opener zlikovec/Getty Images; C6.0l CHRISTIAN DARKIN/SPL; C7.0l SCOTT CAMAZINE/K. VISSCHER/SPL; C7.02 TEK IMAGE/SPL; C7.03 Classic Image/Alamy Stock Photo; C7.08 ASTRID & HANNS FRIEDER MICHLER/SPL; C8 unit opener, C8.04 Art Directors & TRIP/Alamy Stock Photo; C8.02 JAMES KING HOLMES/SPL; C8.03 Chris Mellor/Lonely Planet Images/Getty Images; C8.05 J.C.HURNI, PUBLIPHOTO DIFFUSION/SPL; C8.06 Print Collector/Hulton Archive/Getty Images; C8.08 (all) VvoeVale/iStock/Getty Images Plus/Getty Images; C9 unit opener, C9.0l ROSENFELD IMAGES LTD/SPL; C9.02 NOAA/SPL; C9.03 BEN JOHNSON/SPL; C9.05, fig. C9.13a DIRK WIERSMA/SPL; C9.06 MAXIMILIAN STOCK LTD/SPL; Cl0 PASIEKA/ Getty Images; Cl0.04 DAVID R. FRAZIER/SPL; Cll unit opener shotbydave/Getty Images; Cll.01 SPUTNIK/ SPL; Cll.02, Cll.03 PAUL RAPSON/SPL; Cll.04 ROGER HARRIS/SPL; Cll.05 LEONARD LESSIN/SPL; Cll.06 David Talbot
■
Cambridge IGCSE Combined and Co-ordinated Sciences
Physics
Pl unit opener, Pl.01 GoGo Images Corporation/Alamy Stock Photo; P2 unit opener, P2.03 Gavin Quirke/
Lonely Planet Images/Getty Images; P2.0l TRL LTD./SPL; P2.02, Pl3.09 Cambridge University Press/Nigel
Luckhurst; P3 unit opener, P3.04 ANDREW WHEELER/SPL; P3.0l Chad Slattery/The Image Bank/Getty
Images; P3.02 Getty Images; P3.03 ERICH SCHREMPP/SPL; P4 unit opener Peter Cade/Getty Images; P4.0l Will Steeley/Alamy Stock Photo; PS unit opener, PS.02 ALEXIS ROSENFELD/SPL; PS.01 GUSTOIMAGES/SPL;
P6 unit opener, P6.04, PlS.02 NASA/SPL; P6.0l Jeff Rotman/Nature Picture Library; P6.02 Visions of America,
LLC/Alamy Stock Photo; P6.03, PlO unit opener, PlO.0la,b, Pl0.03, Pl0.04, Pl3.02, fig. Pl3.02a, Pl3.05, Pl3.06, Pl3.07, Pl3.08, Pl4.03b, fig.Pl4.07a, Pl4.04a, b, Pl8 unit opener, fig.Pl8.0l, Pl8.0la, Pl8.02, Pl9.02a, fig.Pl9.03a, fig. Pl9.04a, Pl9.03, Pl9.04, P22.05 ANDREW LAMBERT PHOTOGRAPHY/SPL; P6.05 Bernhard Lang/Photographer's Choice/Getty Images; P7 unit opener P7.03 Kelly Cheng Travel Photography/ Moment/ Getty Images; P7.0l Jim Wileman/Alamy Stock Photo; P7.02 SEY LLOU/ AFP/Getty Images; P7.04 Steve Allen/
Stockbyte/Getty Images; P7.05 Mint Images-Frans Lanting/Mint Images/Getty Images; P8 unit opener, P8.0l ACE STOCK LIMITED/Alamy Stock Photo; P9 unit opener Charity Burggraaf/Getty Images; P9.0l Agencja Fotograficzna Caro/Ala my Stock Photo; Pl0.02 MATT MEADOWS/SPL; Pll unit opener, Pll.03 EDWARD
KINSMAN/SPL; Pll.01 ShaniMiller/Getty Images; Pll.02, Pl2.04, Pl9.04 sciencephotos/Alamy Stock Photo; Pl2 unit opener PASIEKA/Getty Images; Pl2.0l ©Bernard Richardson, Cardiff University; Pl2.02a Mode/ Richard Gleed/Alamy Stock Photo; Pl2.02b Doug Taylor/Alamy Stock Photo; Pl2.03 David Redfern/Redferns/ Getty Images; Pl3 unit opener, Pl3.06, P22 unit opener, P22.08 TEK IMAGE/SPL; Pl3.0l ROYAL GREENWICH
••
OBSERVATORY/SPL; Pl3.03 HANK MORGAN/SPL; Pl3.04 James Balog/Aurora/Getty Images; Fig. Pl3.07a,
Pl4.03a, P20.0l, P22.03 SPL; Pl4 unit opener, Fig. Pl4.08a BERENICE ABBOTT/SPL; Pl4.0l Thomas Kitchin & Victoria Hurst/First Light/Getty Images; Pl4.02 Rick Strange/Alamy Stock Photo; Pl4.05 JOHN FOSTER/
SPL; PlS unit opener, PlS.03 TONY MCCONNELL/SPL; PlS.01 DAVID PARKER/SPL; PlS.04 DAVID R. FRAZIER/ SPL; Pl6 unit opener Sylvie Saivin/ EyeEm/Getty Images; Pl6.0l CORDELIA MOLLOY/SPL; Pl6.02 JEREMY WALKER/SPL; Pl7 unit opener JKboy Jatenipat.Getty Images; Pl9 unit opener, Pl9.0l ROSENFELD IMAGES LTD/SPL; Pl9.02 David J. Green - electrical/Alamy Stock Photo; P20 Monty Rakusen/Getty Images; P21 unit opener, P21.0l ED MICHAELS/SPL; P21.02 standby/Getty Images; P22.0l IBM/SPL; P22.02 PUBLIC HEALTH
ENGLAND/SPL; P22.04 PASCAL G9ETGHELUCK/SPL; Fig. P22.12a Leslie Garland Picture Library/Alamy Stock Photo; P22.06 Crown Copyright - Public Health England; P22.07 Mark Kostich/ VETTA/Getty Images SPL = Science Photo Library
All biology artworks are by Geoff Jones.
This book has been written to help you obtain the knowledge and skills required for your Cambridge IGCSE" Combined Science 0653 or Cambridge IGCSE" Co-ordinated Sciences (Double Award) 0654 course. We hope that you enjoy using it.
All the Biology topics come first, then Chemistry and then Physics. However, you almost certainly won't follow this sequence in your lessons. You will probably find that you study Biology, Chemistry and Physics alongside each other, so you will use different parts of the book in different lessons.
Core and Supplement
Your teacher will tell you whether you are studying:
• Cambridge IGCSE Combined Science 0653 or Cambridge IGCSE Co-ordinated Sciences (Double Award) 0654 • only the Core part of the syllabus, or the Supplement as well.
Cambridge !GCSE Combined Science 0653 is a single award syllabus. This means that your final papers are the equivalent of one IGCSE subject. Cambridge IGCSE Co-ordinated Sciences 0654 is a double award syllabus. In this case, your final papers are the equivalent of two !GCSE subjects.
If you study the Core only, you will be entered for Papers 1 (Multiple Choice (Core)) and 3 (Theory (Core)) and either Paper 5 (Practical Test) or 6 (Alternative to Practical). If you also study the Supplement, you may be entered for Papers 2 (Multiple Choice (Extended)) and 4 (Theory (Extended)), and either Paper 5 (Practical Test) or 6 (Alternative to Practical).
There are sidebars in the margins of the coursebook to show which material relates to each syllabus and paper. If there is no sidebar, it means that everyone will study this material. Use this table to ensure that you study the right material for your syllabus and paper:
You will study the material: Without a sidebar
You will study the material:
You will study the material:
Without a sidebar
Without a sidebar
With a double black sidebar
With a double blue sidebar
With a double blue sidebar
With a single blue sidebar
everything.
You will study
This includes the material:
Without a sidebar
With a single blue sidebar
With a double blue sidebar With a single black sidebar
With a double black sidebar
■
Cambridge IGCSE Combined and Co-ordinated Sciences
Questions Each chapter has several sets of questions within it. Most of these require quite short answers and simply test if you have understood what you have just read or what you have just been taught. At the end of each chapter, there are some longer questions testing a range of material from the chapter. Some of these are past questions from Cambridge exam papers, or similar in style to Cambridge questions. We would like to thank Cambridge International Examinations for permission to reproduce exam questions.
Activities Each chapter contains activities. These will help you to develop the practical skills you will need in your course. There are further activities on the CD-ROM. These are marked with this symbol: • There are two possible papers aimed at testing your practical skills, called Paper 5 and Paper 6 (Practical Test and Alternative to Practical, respectively). Your teacher will tell you which of these you will be entered for. You should try to do the activities in this coursebook no matter which of these papers you are entered for.
Summary At the end of each chapter, there is a short list of the main points covered in the chapter. Remember, though, that these are only very short summaries and you will need to know more detail than this for your course.
CD-ROM There is a CD-ROM in the back of the book. You can use the revision checklists on the CD-ROM to check off how far you have got with learning and understanding each idea. The CD-ROM also contains a set of interactive multiple-choice questions which test whether you know and understand the material from each chapter. You will find some self-assessment checklists on the CD-ROM too, which you can print off and use to assess yourself each time you observe and draw a specimen, construct a results chart, draw a graph from a set of results or plan an experiment. These are all very important skills, and by using these checklists you should be able to improve your performance until you can do them almost perfectly every time. There are some suggestions on the CD-ROM about how you can do well in your course by studying and revising carefully.
Workbooks There are three workbooks to go with this coursebook...: one for each science. If you have the workbooks, you will find them really helpful in developing your skills, such as handling information and solving problems, as well as some of the practical skills.
This chapter covers
sections set out the key topics within each unit, and help with navigation through the chapter.
This chapter covers:
■ ■ ■ ■ ■
the human nervous system
neurones and how they work the difference between voluntary and involuntary actions reflex actions the structure and function of the eye
■ the hormone adrenaline
Key terms
boxes contain clear definitions of important scientific terms in each chapter. ")
■ ■ ■ ■
the hormones insulin and glucagon how humans maintain a constant internal body temperature how plants respond to stimuli the role of auxin in shoot growth.
Worked examples
are featured throughout to provide step-by-step guidance for answering questions. ") WORKED EXAMPLE C4.0l
A solution is made up of two parts: the solute: the solid that dissolves the solvent: the liquid in which it dissolves.
What is the balanced equation for the reaction between magnesium and oxygen?
Step 1: Make sure you know what the reactants and
products are. For example, magnesium burns in air (oxygen) to form magnesium oxide.
Step 2: From this you can write out the word equation: Step 3: Write out the equation using the formulae of
Tip boxes contain advice for students to avoid common
misconceptions and provide support for answering questions.
)
TIP
Remember that ice is not always at 0 °C- it may be colder than that. When you take ice from a freezer, it may be as cold as -20 °C.
magnesium+ oxygen ➔ magnesium oxide the elements and compounds: Mg+02 ➔ MgO
Remember that oxygen exists as diatomic molecules. This equation is not balanced: there are two oxygen atoms on the left, but only one on the right.
Step 4: Balance the equation:
2Mg+02 ➔ 2Mg0
■
Cambridge I GCSE Combined and Co-ordinated Sciences Activity sections th ro u ghout each chapter p rovide guida nce for condu cti ng pra ctical investigations.
}
ACTIVITY C7.05
®
Questions 11 a re featu red throughout each cha pter to assess students' knowledge and u n dersta nding of science. QUEST I O N S
B2.01
The factors affecting reaction rate
B2.02
Skills:
B2.03
AO3.l Demonstrate knowledge of how to safely use techniques, apparatus and materials (including following a sequence of instructions where appropriate) AO3.2 Plan experiments and i nvestigations
AO3.4 I nterpret and evaluate experimental observations and data
•
List three exa m ples of diffusion in livi ng orga n isms.
You will need to think a bout you r knowledge of pa rticle th eory to a n swer this q u estion. a
b
AO3.3 M a ke and record observations, measurements and estimates
What effect does an i ncrease i n tempe rature have on the kinetic energy of molecules of a gas or a solute?
Predict a n d expla i n how an increase i n temperature will affect the rate of diffusion of a solute. Check the introd uction and the cover flap for i nfo rmation on how to use the side bars in the margi ns.
AO3.5 Eval uate methods and suggest possible improvements
ffi
Defi ne diffusion.
Wear eye protection. Sulfuric acid is corrosive.
You must plan an investigation to d iscover how one chosen factor affects the rate of a chemical reaction. 1
}
Mg + H 2SO4 ➔ M gSO4 + H2
Meas u re 10 cm3 of 2 mol/dm 3 sulfu ric acid i nto a boi l i n g tu be.
2 Add a 5 cm stri p of magnesi u m ri bbon and sta rt a stopclock.
3 When th e reaction stops, record the time taken. 4 List the factors that could speed up or slow down this reaction.
5 Choose o n e of these factors a n d plan a n i nvestigatio n t o discover how i t affects t h e rate.
6 You r i nvestigation sho uld prod uce sufficient results to ena b le you to d raw a gra p h.
A worksheet is included on the CD-ROM. The Notes on activities for teachers/technicians contain details of how this experiment can be used as an assessment of skills AO3.2 and AO3.5.
You should know:
■
how diffusion resu lts from the ra ndom movement of particles
■ the factors that affect the rate of diffusion
■
why d iffusion is i mportant to cells and livi ng orga nisms
At the end of each cha pter, a Summary is incl uded to recap the key topics.
}
■ ■ ■
the i m portance of water as a solvent
a bout osmosis, which is a special kind of diffusion, i nvolving water molecu les
how osmosis affects a n i m a l cells and
plant cells.
How to use this book I 1 11 1 wing the summa ry, th ere will be selection of exam-style End of chapter questions to help students to pre p a re for the type of , I l l! " lions on the IGCSE Combined or I GCSE Co-ordi nated Sciences exams.
End-of-chapter questions .1
When a force m oves, it does work. Copy a nd co m plete the fo llowing sentences, writi ng more or less in the spaces. a
b
When it m oves, a bigger force does . . . . . . . . . . . . . . . . . work than a smaller force.
The greater the d ista nce moved by the force, the . . . . . . . . . . . . . . . . . work it does.
Power tells us a bout how q u ickly work is done. Copy and complete the fol lowi ng sentences,
writi ng work or energy in the spaces. a
b
Power is the rate at w h ich . . . . . . . . . . . . . . . . . is tra nsferred.
b
[ 1]
[l]
Power is the rate at wh ich . . . . . . . . . . . . . . . . . is done.
[l] [l]
Write this equation i n words.
[2] [3]
We can calculate work done using this equation: W = F x d. a
}
Copy a n d co mplete the table to show the u n its of each q u a ntity in the equation. Qua ntity
w
I U n it
■
F 4
d
Omar a nd Ahmed a re lifting weights in the gym . Each lifts a weight of 200 N . O m a r lifts the
weight to a h eight of 2.0 m , wh ereas A h m ed l ifts it to a h eight of 2.1 m. Who does m o re work i n lifting the weight? Expla i n how you know.
M i llie and Lily a re identica l twins who e njoy swi m m i ng. Their a rms an d legs provide
the force needed to move them through the water. Mi llie can swi m 25 m i n 50 s. Lily can swim 100 m i n 250 s.
a
b
Ca lcu late the swi m m i ng speed of each twi n .
Which twi n has the greater powe r when swi m m i ng? Explain how you can tell.
Write a word equation showing h ow work done a n d energy transferred a re related.
[2]
[2] [2]
[2]
I
(his chapter covers:
the characteristics of livi ng thi ngs the structure of animal cells and plant cel ls the functions of the different pa rts of cel ls h ow to calcu late magnification.
1.01 Characteristics of living things l \lology is the study of living things, which are often , llled organisms. Living organisms have seven features 1 >1 characteristics which make them different from ,l>jects that are not alive (Figure B1.01). The definitions
movement: a n action by an organism causing a cha nge of position or place
respiration: the chemical reactions in cells that break down nutrient molecu les and release energy
sensitivity: the abi lity to detect and respond to cha nges in the envi ron ment
of these characteristics are shown in the key terms box. You should learn these definitions now, but you will find out much more about each of them later in this book.
growth: a permanent increase i n size
reproduction: the processes that m a ke m ore of the same kind of organism excretion: removal from organisms of toxic materials and su bstances in excess of req u i rements
nutrition: taking in of materials for energy, growth and development
Ca m bridge IGCSE Com bined a nd Co-ordi nated Sciences Growth All o rga nisms begin sma ll and get la rger, by the growth of their cells and by adding new cells to their bodies.
Excretion All orga n isms produce u nwanted or toxic waste produ cts as a resu lt of their meta bolic reactions, and these m ust be rem oved from the body.
Movement All organisms a re a ble to m ove to some extent. M ost a ni ma ls can move their whole body fro m place to p lace, and plants can slowly m ove parts of themselves.
Reproduction Organ is ms a re able to m a ke n ew orga n is ms o f th e sa m e species as themselves.
Figu re B1.01 Cha racteristi cs of livin g orga nisms.
movement: a n action by a n organism or part of a n organ ism causi ng a change of position or place respiration: the chemical reactions in cells that brea k down nutrient molecules and release energy for metabol ism
sensitivity: the abi lity to d etect or sense stimuli i n t h e i nterna l or external environment a n d to make appropriate responses
growth: a permanent increase in size and dry mass by a n increase in cell number o r cell size or both
I n a d d ition to these seven c h a racte ristics, living o rgan isms h ave a n other fea t u re i n co m m on: w h e n w e stu d y liv in g
Sensiti'(,ity All orga nisms pick u p i nfo rmation about ch a nges i n their enviro n ment, and react to the cha nges.
Nutrition Organisms take su bstances from their environ ment and use them to provide energy or materials to m a ke new cells.
Respiration All orga nisms break down glucose and other su bsta nces i nside their cells, to release en ergy that they can use.
reproduction: the processes that make more of the same ki nd of organism
excretion: removal from organisms of the waste prod ucts of meta bolism (chemical reactions in cells including respiration), toxic materials and su bstances in excess of requirements nutrition: ta king in of materials for energy, growth a n d development; plants requ i re light, carbon dioxide, water and ions; a nimals need orga nic com pounds and ions a nd usua lly need water
o rga nisms u n de r a m i c roscope, we can see that they a re a l l m a d e of ce lls.
Bl: Cells
.02 Cells
II 1 1 I /J n i s m s a re m a d e of ce lls. Cells a re very 1 1 1, i ll, o la rge o rga n isms conta i n m i llions of cells. ,1 11 1 H orga n isms a re u n ice l l u l a r, w h ich means that I I 1 1 1y ,,r made of j ust a si ngle cell. Bacteria and yeast a re
cell membrane
, 1 1 1 1 p les of si ngle-celled o rga n is m s .
M roscopes
1 1 1 , I ' 1 cells c lea rly, you need to use a mi crosco pe ( 1 1)\1 1 1 Bl.02). The ki n d of m i c roscope used in a
1 l tn I l a b o ratory is c a l led a light m icroscope beca use I I 1 1 1 1 1 'S li ght t h rough the piece of a n i m a l o r plant 1 1 1 1 , 1 1 loo ki n g at. It uses glass lenses to magn ify a n d
I , 1 1 1 /'1 L h e i m a ge. A very good light m icroscope ca n 1 1 1i 11:1 1 ify a b o ut 1500 t i m es, so t h a t a l l the struct u res i n 1 11 1 1 1 1 1 Bl.03 a n d Bl.04 c a n b e seen.
I 'l 1 1 1 i c m i c rogra phs of pla nt and a n i m a l cells a re shown i n l 1 1 1, 1p,( s B1.01 a n d Bl.02. A m i c rogra ph is a pictu re m a d e
1 1 l l tp, 1 1 l 1 11 I,
m i c roscope. A p hoto m i c rogra ph is a pictu re m a d e light m i crosco pe.
1 1 1 ,1 1 eve n sma ller t h i n gs i n s i d e a cell, a n electron 1 1 111 1 c co pe is used. T h is uses a bea m of electro ns
cytoplasm
n uclear envelope
Figu re B1.03 A typical a n i m a l cell - a liver ce ll - as seen
using a l ight microscope.
i n stea d of light a n d can magn ify up to 500 000 t i m es . Th is m e a n s that a lot more d et a i l ca n be seen i n s i d e
a c e l l . W e c a n see m a ny stru ctu res more clea rly, a n d a lso some struct u res that cou ld n ot b e seen a t a l l with a light m i c roscope. Pictures m a d e using an electron m icroscope a re cal led electron m i crographs.
1 1 11 1 human eye can not see 1 1 1t> 1,L cells.
A 1 1 nd lens magn ifies , 11,out x 1 0. Cells can 1111 ,n be seen as dots.
The light microscope magn ifies up to x 1500. With a light microscope you ca n see some structu res inside a cell, such as a n ucleus.
I I) 1 1 1 B1.02 Eq u i pment used fo r looking a t biological m ateria l.
= = = = = An electron m icroscope magnifies up to x 10 mi llion. With a n electron m ic roscope much more d eta il can be seen.
■
Cam bridge IGCSE Combined and Co-ordinated Sciences
n ucleus
nuclear envelope
cytoplasm
/
---1,-tt-- la rge vacuole conta i ning cell sap
mem brane a round vacuole
I■
starch gra i n inside ch loroplast
Figu re B1.04 A typica l pla nt cell - a pa lisade ce ll - as seen
using a light m icrosco pe.
cytoplasm
I m a ge B1.02 Ce l ls fro m the tra chea (windpi pe) of a m a m mal, seen through a light m icroscope (x 300).
ACTIVITY B1 .01
Skill:
Making drawings of biological specimens
A03.3 Observing, measuring and recording
Scientists need to be a ble to look closely at specimens either with the naked eye or using a microscope - and note significant features in them. It is also im portant to be able to make scientific d rawings. These need to be simple but clear. I n this Activity, you will be provided with a specimen of a n a nimal t o d raw.
I mage B1.01 Ma ny p la nt cel ls co ntai n green stru ctu res,
c a lled ch lo ro plasts. Even if it d oes not have ch loroplasts,
you ca n sti ll identify a pla nt cell beca use it has a cell wall
a round it (x 2000).
H ere a re some points to bear i n mind when you d raw: ■ M a ke good use of the space on you r sheet of pa per. You r d rawing should be la rge, b u t do leave space aro u nd i t so that you have room for la bels.
B1: Cells
1 lwc1y use a sharp H B (medi u m hard) pencil and have a ,, ,n(i eraser with you. I f ( p all li nes si ngle and clear. I l! , 1 1 't use shading u n less it is a bsolutely necessary. I >1 in'L use colours. i . 1kc time to get the outl i n e of your d rawi ng correct fi rst, l l()wing the right proportions. l
, , 1 1 some poi nts to bear in mind when you , •I .i ci iagra m: l J•,t • ruler to draw each l a bel line. M, 1k sure the end of the label line actually touches 1 I i • tructure being labelled. W1 1 I the la bels horizontally. I , t p the la bels well away from the edges of , I l l Ir d rawing.
The following a re two very i m portant things to n otice:
■ ■
You must use the same u nits for all the measu rements. Usually, milli metres a re the best u nits to use. You should not include a ny units with the fi nal answer. Magnification does not have a un it. However, you must i nclude the 'times' sign. If you read it out loud, you would say 'times five'.
Questions Al M easu re the length of the lowest 'tail' (it is rea l ly ca lled an a ppendage) on the centipede below. Write your a n swer i n m illi metres.
AC TIVITY B1.02
I ulating magnification 11111:
Observing, measuring and recording t 1 1 1 gs and photogra phs of biological specimens a re , , illy made at a different size from the actual o bject. 1, 1 1 1. ignification of a diagram or photogra ph is h ow , i , 1 1 lc1rger it is than the rea l thi ng: size in d rawing or photograp h .. . 1 1 1 g n 1f1 cat1on = _______;:::...._....:...._.....:::..__:___ size of the rea l object
, , ,m 1 p le, measure the length of the spider's body i n 1 1 Igra m. You should find that it i s 4 0 m m long.
A2 The real length of the a p pend age was 10 m m . U s e this, and your a nswer t o question Al, to ca lcu late the magnification of the d rawing of the centi pede.
QU ESTIONS
B1.01
B1.02
How many times can a good light m icroscope magnify?
If an o bject was 1 m m across, how big wou ld it look i f it were magnified ten times?
Cell structure Cell membrane
, •. 1 1 pider was 8 mm long. So we can ca lculate the , 1 1 1 1 lion like this: length i n d rawi ng magn ification = ------ length of rea l spider =
40 m m 8 mm
=xS
W hatever sort of a n i m a l or p la nt they come from , a l l cells have a cell membrane (so m eti mes c a lled the cell su rface m e m b ra n e) a ro u n d the outside. Inside the cell m e mbrane is a jelly-like su bsta nce c a l led cytoplasm, i n which a re fou n d m a ny s m a l l structure s c a l led o rganelles. T h e m ost obvious of these o rga n e lles i s u s u a lly the nucleus. In a plant cell, the n u cleus is very d ifficult to see, beca u se it is right a g a i nst the cell wall.
The cell m e m b ra n e is a very thin layer of p rotei n a n d fat. It is very i m porta nt to the cel l beca use it contro ls w h at goes in a n d out of it. It is partially permeable, w h i c h means that it will let some su bsta n ces through but n ot others.
■
I
Cambridge IGCSE Combined and Co-ordinated Sciences
Cell wall
All p la nt cells a re s u rro u n d e d by a cell wall m a d e m a i n ly o f cellulose. P a p e r, w h i c h is m a d e fro m ce l l w a l ls, is a ls o m a d e of c el l u lose. A n i m a l cells
n eve r h ave c e l l w a l ls made of cellu lose. Cellu lose b e l o n gs to a gro u p of s u bsta nces c a l l e d polysaccha rid es, w hi ch a re d escri b e d i n C h a pter B2. Cellu lose fo r m s fi b res that criss-cross over one a n oth e r
t o fo rm a very s t ro n g cove ri n g t o t h e c e l l ( I m age B1.03). This h e lps to p rotect and s u pport t h e cell. I f t h e c e l l a bsorbs a l o t of w a t e r a n d swe lls, t h e ce l l w a l l sto p s it fro m b u rsti ng.
Beca u se of t h e s p a ces between fi b res, even very la rge
mo lecu les a re a b le to go t h ro u gh the cellu lose cell wall. It is the refore s a i d to be fu lly perm ea b le .
Cytoplasm
Cyto p l a s m is a clear j e l ly. It i s nea rly a l l water; a b o u t 70% is water in m a n y cel ls. M a ny su bsta nces a re d isso lved in it,
especi a l ly p rotei n s . M a ny d iffere nt m etabolic reactions (th e c h e m ica l reactions of l ife) take p l a ce i n the cytoplasm.
Vacuoles
A vacuole is a space in a cell, su rro u n d e d by a m e m b ra n e a n d conta i n i n g a solution. Plant cells have very large vacuoles, which cont a i n a solution of sugars and oth e r substa nces, cal led cell sap. A fu l l vac u o le p resses out.wards o n the rest of the cell, and h e l ps to kee p it in s ha pe. A n i m a l cells have m u c h s m a ller m e m b ra n e-bo u n d spaces, ca lled
vesicles, which m ay conta i n n utrients o r water.
Chloroplasts
C h loroplasts a re n ever fo u n d i n a n i m a l ce lls, bu t most
of the ce lls i n the green pa rts of pla nts have t h e m . They co nta i n a gre e n colou ring or pigment ca lled ch lorophyll. Ch loro p hyll a bsorbs e n e rgy fro m s u n light, and this e n e rgy is then u sed fo r m a ki n g food fo r the pla nt by photosynthesis (Cha pte r B4).
Ch loro plasts often co nta i n sta rch gra i ns, which have b e e n m a d e by photosynthesis. A n i m a l c e l l s never co nta i n sta rch gra i n s . S o m e a n i m a l cells, h oweve r, do have gra n u les (ti ny grai ns) of a n oth er s u bsta nce s i m i l a r to starch, ca lled glycoge n. These gra n u les a re fou n d i n the cytoplasm, not i ns i d e ch loroplasts.
Nucleus
The n u cleus is w h e re the g e n etic i n fo r m ation is sto red . This h e l ps the cell to m a ke the right s o rts of p roteins. Th e i nfo rmation is kept o n the ch ro mosomes, wh ich a re
i n h e rited fro m t h e o rga n ism's parents. T he c h ro m osomes a re made of DNA.
C h ro m osomes a re very l o n g, but so t h i n that they can not easily be seen even using the electron m i croscope.
H owever, when t h e cell is d ividing, t h ey beco m e short a n d thi c k a n d ca n be seen with a goo d light m i c roscope.
Ta b le B1.01 co m pa res so m e featu res of plant cells and a n i m a l ce lls.
Plant cells
have a cel l u lose cell wall
outs i d e the cell m e m b ra n e have a cel l m e m b ra n e have cytoplasm have a n u cleus
often have ch loroplasts conta i n i n g ch lorophyll
often have l a rge vacuoles conta i n i ng ce l l s a p
often have sta rch gra i ns I mage B1.03 Cellu lose fibres from a plant cell wall. This
picture was taken using a n electron m icroscope (x 50 000).
\\
a re often regu l a r in s h a p e
I A n i m a l cells
h ave n o ce l l wall
h ave a cel l m e m b ra n e h ave cyto p la s m h ave a n u cleus
h ave no ch loro p l a sts
h ave o n ly s m a l l vacuoles n eve r h ave sta rc h
gra i ns; so m eti m es h ave glycogen gra n u les
a re often i r regu l a r i n s h a pe
Ta ble B1.01 A co m parison of plant a n d animal cells.
Bl: Cells
ACTIVITY 81.03
•
Using a m icroscope
Practise using a microscope to look at very