FHSST Authors The Free High School Science Texts: Textbooks for High School Students Studying the Sciences Physical Science Grade 11 Version 0.5 September 9, 2010 ii Copyright 2007 “Free High School Science Texts” Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front- Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled “GNU Free Documentation License”. STOP!!!! Did you notice the FREEDOMS we’ve granted you? Our copyright license is different! 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Thousands of hours went into making them and they are a gift to everyone in the education community. iii FHSST Core Team Mark Horner ; Samuel Halliday ; Sarah Blyth ; Rory Adams ; Spencer Wheaton FHSST Editors Jaynie Padayachee ; Joanne Boulle ; Diana Mulcahy ; Annette Nell ; Ren´e Toerien ; Donovan Whitfield FHSST Contributors Sarah Abel ; Dr. Rory Adams ; Andrea Africa ; Ben Anhalt ; Prashant Arora ; Raymond Barbour ; Richard Baxter ; Tara Beckerling ; Tim van Beek ; Jennifer de Beyer ; Dr. Sarah Blyth ; Sebastian Bodenstein ; Martin Bongers ; Stephan Brandt ; Craig Brown ; Graeme Broster ; Deanne de Bude ; Richard Case ; Fa n ny Cherblanc ; Dr. Christin e Chung ; Brett Cocks ; Andrew Craig ; Tim Crombie ; Dan Crytser ; Dr. Anne Dabrowski ; Laura Daniels ; Sean Dobbs ; Esmi Dreyer ; Matthew Duddy ; Fernando Durrell ; Dr. Dan Dwyer ; Frans van Eeden ; Alex Ellis ; Tom Ellis ; Giovanni Franzoni ; Ingrid von Glehn ; Tamara von Glehn ; Lindsay Glesener ; Kevin Godby ; Dr. Vanessa Godfrey ; Dr. Johan Gonzalez ; Hemant Gopal ; Dr. S te ph a ni e Gould ; Umeshree Govender ; Heather Gray ; Lynn Greeff ; Dr. Tom Gutierrez ; Brooke Haag ; Kate Hadley ; Dr. Sam Halliday ; Asheena Hanuman ; Dr Melanie Dymond Harper ; Dr. Nicholas Harrison ; Neil Hart ; Nicholas Hatcher ; Dr. William P. 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We intend to work with all who are willing to help make this a continuously evolving resource! www.fhsst.org iv Contents I Chemistry 1 1 Atomic Combinations - Grade 11 3 1.1 Why do atoms bond? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Energy and bonding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.3 What happens when atoms bond? . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.4 Covalent Bonding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.4.1 The nature of the covalent bond . . . . . . . . . . . . . . . . . . . . . . 5 1.5 Lewis notation and molecular structure . . . . . . . . . . . . . . . . . . . . . . . 9 1.6 Electronegativity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 1.6.1 Non-polar and polar covalent bonds . . . . . . . . . . . . . . . . . . . . 13 1.6.2 Polar molecules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1.7 Ionic Bonding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1.7.1 The nature of the ionic bond . . . . . . . . . . . . . . . . . . . . . . . . 14 1.7.2 The crystal lattice structure of ionic compounds . . . . . . . . . . . . . . 16 1.7.3 Properties of Ionic Compounds . . . . . . . . . . . . . . . . . . . . . . . 16 1.8 Metallic bonds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 1.8.1 The nature of the metallic bond . . . . . . . . . . . . . . . . . . . . . . 16 1.8.2 The properties of metals . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1.9 Writing chemical formulae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 1.9.1 The formulae of covalent compounds . . . . . . . . . . . . . . . . . . . . 18 1.9.2 The formulae of ionic compounds . . . . . . . . . . . . . . . . . . . . . 20 1.10 The Shape of Molecules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 1.10.1 Valence Shell Electron Pair Repulsion (VSEPR) theory . . . . . . . . . . 22 1.10.2 Determining the shape of a molecule . . . . . . . . . . . . . . . . . . . . 22 1.11 Oxidation numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 1.12 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2 Intermolecular Forces - Grade 11 31 2.1 Types of Intermolecular Forces . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 2.2 Understanding intermolecular forces . . . . . . . . . . . . . . . . . . . . . . . . 34 2.3 Intermolecular forces in liquids . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 2.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 v CONTENTS CONTENTS 3 Solutions and solubil ity - Grade 11 41 3.1 Types of solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 3.2 Forces and solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 3.3 Solubility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 3.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 4 Atomic Nuclei - Grade 11 47 4.1 Nuclear structure and stability . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 4.2 The Discovery of Radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 4.3 Radioactivity and Types of Radiation . . . . . . . . . . . . . . . . . . . . . . . . 48 4.3.1 Alpha (α) particles and alpha decay . . . . . . . . . . . . . . . . . . . . 49 4.3.2 Beta (β) particles and beta decay . . . . . . . . . . . . . . . . . . . . . 49 4.3.3 Gamma (γ) rays and gamma decay . . . . . . . . . . . . . . . . . . . . . 50 4.4 Sources of radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 4.4.1 Natural background radiation . . . . . . . . . . . . . . . . . . . . . . . . 53 4.4.2 Man-made sources of radiation . . . . . . . . . . . . . . . . . . . . . . . 53 4.5 The ’half-life’ of an element . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 4.6 The Dangers of Radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 4.7 The Uses of Radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 4.8 Nuclear Fission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 4.8.1 The Atomic bomb - an abuse of nuclear fission . . . . . . . . . . . . . . 59 4.8.2 Nuclear power - harnessing energy . . . . . . . . . . . . . . . . . . . . . 60 4.9 Nuclear Fusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 4.10 Nucleosynthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 4.10.1 Age of Nucleosynthesis (225 s - 10 3 s) . . . . . . . . . . . . . . . . . . . 62 4.10.2 Age of Ions (10 3 s - 10 13 s) . . . . . . . . . . . . . . . . . . . . . . . . . 62 4.10.3 Age of Atoms (10 13 s - 10 15 s) . . . . . . . . . . . . . . . . . . . . . . . 62 4.10.4 Age of Stars and Galaxies (the universe tod ay) . . . . . . . . . . . . . . 63 4.11 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 5 Thermal Pr operties and Ideal Gas es - Grade 11 65 5.1 A review of the kinetic theory of matter . . . . . . . . . . . . . . . . . . . . . . 65 5.2 Boyle’s Law: Pressure and volume of an enclosed gas . . . . . . . . . . . . . . . 66 5.3 Charles’ Law: Volume and Temperature of an enclosed gas . . . . . . . . . . . . 72 5.4 The relationship between temperature and pressure . . . . . . . . . . . . . . . . 76 5.5 The general gas equation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 5.6 The ideal gas equation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 5.7 Molar volume of gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 5.8 Ideal gases and non-ideal gas behaviour . . . . . . . . . . . . . . . . . . . . . . 86 5.9 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 vi CONTENTS CONTENTS 6 Quantitative As pects of Chemical Change - Grade 11 91 6.1 The Mole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 6.2 Molar Mass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 6.3 An equation to calculate moles and mass in chemical reactions . . . . . . . . . . 95 6.4 Molecules and compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 6.5 The Composition of Substances . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 6.6 Molar Volumes of Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 6.7 Molar concentrations of liquids . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 6.8 Stoichiometric calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 6.9 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 7 Energy Changes In Chemical Reactions - Grade 11 113 7.1 What causes the energy changes in chemical reactions? . . . . . . . . . . . . . . 113 7.2 Exothermic and endothermic reactions . . . . . . . . . . . . . . . . . . . . . . . 113 7.3 The heat of reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 7.4 Examples of endothermic and exothermic reactions . . . . . . . . . . . . . . . . 117 7.5 Spontaneous and non-spontaneous reactions . . . . . . . . . . . . . . . . . . . . 118 7.6 Activation energy and the activated complex . . . . . . . . . . . . . . . . . . . . 119 7.7 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 8 Types of Reactions - Grade 11 125 8.1 Acid-base reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 8.1.1 What are acids and bases? . . . . . . . . . . . . . . . . . . . . . . . . . 125 8.1.2 Defining acids and bases . . . . . . . . . . . . . . . . . . . . . . . . . . 125 8.1.3 Conjugate acid-base pairs . . . . . . . . . . . . . . . . . . . . . . . . . . 127 8.1.4 Acid-base reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 8.1.5 Acid-carbonate reactions . . . . . . . . . . . . . . . . . . . . . . . . . . 132 8.2 Redox reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 8.2.1 Oxidation and reduction . . . . . . . . . . . . . . . . . . . . . . . . . . 135 8.2.2 Redox reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 8.3 Addition, substitution and elimination reactions . . . . . . . . . . . . . . . . . . 138 8.3.1 Addition reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 8.3.2 Elimination reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 8.3.3 Substitution reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 8.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 9 The Lithos phere - Grade 11 145 9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 9.2 The chemistry of the earth’s crust . . . . . . . . . . . . . . . . . . . . . . . . . 146 9.3 A brief history of mineral use . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147 9.4 Energy resources and their uses . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 9.5 Mining and Mineral Processing: Gold . . . . . . . . . . . . . . . . . . . . . . . . 149 9.5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 vii CONTENTS CONTENTS 9.5.2 Mining the Gold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 9.5.3 Processing the gold ore . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 9.5.4 Characteristics and uses of gold . . . . . . . . . . . . . . . . . . . . . . . 151 9.5.5 Environmental impacts of gold mining . . . . . . . . . . . . . . . . . . . 153 9.6 Mining and mineral processing: Iron . . . . . . . . . . . . . . . . . . . . . . . . 154 9.6.1 Iron mining and iron ore processing . . . . . . . . . . . . . . . . . . . . . 154 9.6.2 Types of iron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 9.6.3 Iron in South Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 9.7 Mining and mineral processing: Phosphates . . . . . . . . . . . . . . . . . . . . 157 9.7.1 Mining phosphates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 9.7.2 Uses of phosphates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 9.8 Energy resources and their uses: Coal . . . . . . . . . . . . . . . . . . . . . . . 159 9.8.1 The formation of coal . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 9.8.2 How coal is removed from the ground . . . . . . . . . . . . . . . . . . . 160 9.8.3 The uses of coal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 9.8.4 Coal and the South African economy . . . . . . . . . . . . . . . . . . . . 161 9.8.5 The environmental impacts of coal mining . . . . . . . . . . . . . . . . . 161 9.9 Energy resources and their uses: Oil . . . . . . . . . . . . . . . . . . . . . . . . 162 9.9.1 How oil is formed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 9.9.2 Extracting oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 9.9.3 Other oil products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 9.9.4 The environmental impacts of oil extraction and use . . . . . . . . . . . 163 9.10 Alternative energy resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 9.11 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 10 The Atmosphere - Grade 11 169 10.1 The composition of the atmosphere . . . . . . . . . . . . . . . . . . . . . . . . 169 10.2 The structure of the atmosphere . . . . . . . . . . . . . . . . . . . . . . . . . . 170 10.2.1 The troposphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170 10.2.2 The stratosphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170 10.2.3 The mesosphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 10.2.4 The thermosphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 10.3 Greenhouse gases and global warming . . . . . . . . . . . . . . . . . . . . . . . 174 10.3.1 The heating of the atmosphere . . . . . . . . . . . . . . . . . . . . . . . 174 10.3.2 The greenhouse gases and global warming . . . . . . . . . . . . . . . . . 174 10.3.3 The consequences of global warming . . . . . . . . . . . . . . . . . . . . 177 10.3.4 Taking action to combat global warming . . . . . . . . . . . . . . . . . . 178 10.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 II Physics 183 11 Vectors 185 11.1 Introducti on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 viii CONTENTS CONTENTS 11.2 Scalars and Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 11.3 Notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 11.3.1 Mathematical Representation . . . . . . . . . . . . . . . . . . . . . . . . 186 11.3.2 Graphical Representation . . . . . . . . . . . . . . . . . . . . . . . . . . 186 11.4 Directions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 11.4.1 Relative Directions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 11.4.2 Compass Directions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187 11.4.3 Bearing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187 11.5 Drawing Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 11.6 Mathematical Properties of Vectors . . . . . . . . . . . . . . . . . . . . . . . . . 189 11.6.1 Adding Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 11.6.2 Subtracting Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 11.6.3 Scalar Multiplication . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192 11.7 Techniques of Vector Addition . . . . . . . . . . . . . . . . . . . . . . . . . . . 192 11.7.1 Graphical Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 11.7.2 Algebraic Addition and Subtraction of Vectors . . . . . . . . . . . . . . . 198 11.8 Components of Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 11.8.1 Vector addition using components . . . . . . . . . . . . . . . . . . . . . 206 11.8.2 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 11.8.3 End of chapter exercises: Vectors . . . . . . . . . . . . . . . . . . . . . . 211 11.8.4 End of chapter exercises: Vectors - Long questions . . . . . . . . . . . . 212 12 Force, Momentum and Impulse - Grade 11 215 12.1 Introducti on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215 12.2 Force . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215 12.2.1 What is a force? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215 12.2.2 Examples of Forces in Physics . . . . . . . . . . . . . . . . . . . . . . . 216 12.2.3 Systems and External Forces . . . . . . . . . . . . . . . . . . . . . . . . 217 12.2.4 Force Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218 12.2.5 Free Body Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220 12.2.6 Finding the Resultant Force . . . . . . . . . . . . . . . . . . . . . . . . . 221 12.2.7 Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222 12.3 Newton’s Laws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223 12.3.1 Newton’s First Law . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223 12.3.2 Newton’s Second Law of Motion . . . . . . . . . . . . . . . . . . . . . . 225 12.3.3 Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238 12.3.4 Newton’s Third Law of Motion . . . . . . . . . . . . . . . . . . . . . . . 240 12.3.5 Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245 12.3.6 Different types of forces . . . . . . . . . . . . . . . . . . . . . . . . . . . 245 12.3.7 Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252 12.3.8 Forces in equilibrium . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253 12.3.9 Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256 ix CONTENTS CONTENTS 12.4 Forces between Masses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259 12.4.1 Newton’s Law of Universal Gravitation . . . . . . . . . . . . . . . . . . . 259 12.4.2 Comparative Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . 260 12.4.3 Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262 12.5 Momentum and Impulse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264 12.5.1 Vector Nature of Momentum . . . . . . . . . . . . . . . . . . . . . . . . 266 12.5.2 Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267 12.5.3 Change in Momentum . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268 12.5.4 Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 12.5.5 Newton’s Second Law revisited . . . . . . . . . . . . . . . . . . . . . . . 270 12.5.6 Impulse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 12.5.7 Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273 12.5.8 Conservation of Momentum . . . . . . . . . . . . . . . . . . . . . . . . . 274 12.5.9 Physics in Action: I mp ul se . . . . . . . . . . . . . . . . . . . . . . . . . 277 12.5.10 Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278 12.6 Torque and Levers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279 12.6.1 Torque . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279 12.6.2 Mechanical Advantage and Levers . . . . . . . . . . . . . . . . . . . . . 282 12.6.3 Classes of levers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284 12.6.4 Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285 12.7 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286 12.8 End of Chapter exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287 13 Geometrical Optics - Grade 11 305 13.1 Introducti on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305 13.2 Lenses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305 13.2.1 Converging Lenses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307 13.2.2 Diverging Lenses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318 13.2.3 Summary of Image Prop er tie s . . . . . . . . . . . . . . . . . . . . . . . 322 13.3 The Human Eye . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322 13.3.1 Structure of the Eye . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323 13.3.2 Defects of Vision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324 13.4 Telescopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325 13.4.1 Refracting Telescopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325 13.4.2 Reflecting Telescopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326 13.4.3 Southern African Large Telescope . . . . . . . . . . . . . . . . . . . . . 326 13.5 Microscopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327 13.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328 13.7 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329 x [...]... delocalised electrons which are attracted to the nuclei (figure 1 .11) 16 CHAPTER 1 ATOMIC COMBINATIONS - GRADE 11 1.8 Definition: Metallic bond Metallic bonding is the electrostatic attraction between the positively charged atomic nuclei of metal atoms and the delocalised electrons in the metal + + + + + + + + + + + + + + + + + + + + + + + + + + + Figure 1 .11: Positive atomic nuclei (+) surrounded by delocalised... electrons, and therefore the electrons that are in the bond that forms between this ion and the nitrogen atom, come only from the nitrogen H ×× ×× ×× H ×× ×• ו ו H N H + [H]+ H N H ו H 11 1.6 CHAPTER 1 ATOMIC COMBINATIONS - GRADE 11 Exercise: Atomic bonding and Lewis notation 1 Represent each of the following atoms using Lewis notation: (a) beryllium (b) calcium (c) lithium 2 Represent each of the following... the product that is formed chemical formula of the product name of the product 5 A chemical compound has the following Lewis notation: Y ×× ×× ×• X ו H (a) (b) (c) (d) (e) 1.6 How many valence electrons does element Y have? What is the valency of element Y? What is the valency of element X? How many covalent bonds are in the molecule? Suggest a name for the elements X and Y Electronegativity Electronegativity... chapter exercises 407 19 Electric Circuits - Grade 11 409 19.1 Introduction 409 19.2 Ohm’s Law 409 19.2.1 Definition of Ohm’s Law 409 19.2.2 Ohmic and non-ohmic conductors 411 19.2.3 Using Ohm’s Law 412 19.3 Resistance ... potassium will be needed for every one atom of iodine Step 3 : Write the chemical formula The chemical formula for potassium iodide is therefore: KI 20 CHAPTER 1 ATOMIC COMBINATIONS - GRADE 11 1.9 Worked Example 11: Formulae of ionic compounds Question: Write the chemical formula for sodium sulfate Answer Step 4 : Write down the ions that make up the compound Sodium sulfate contains sodium ions and...CONTENTS CONTENTS 14 Longitudinal Waves - Grade 11 331 14.1 Introduction 331 14.2 What is a longitudinal wave? 331 14.3 Characteristics of Longitudinal Waves 332... 425 19.6 Summary 427 19.7 End of chapter exercise 427 xii CONTENTS CONTENTS 20 Electronic Properties of Matter - Grade 11 431 20.1 Introduction 431 20.2 Conduction 431 20.2.1 Metals 433 20.2.2 Insulator ... 438 20.5 End of Chapter Exercises 439 A GNU Free Documentation License 441 xiii CONTENTS CONTENTS xiv Part I Chemistry 1 Chapter 1 Atomic Combinations - Grade 11 When you look at the matter, or physical substances, around you, you will realise that atoms seldom exist on their own More often, the things around us are made up of different atoms that have been joined... another As they move closer together, there are three forces that act on the atoms at the same time These forces are shown in figure 1.1 and are described below: 3 1.2 CHAPTER 1 ATOMIC COMBINATIONS - GRADE 11 (1) (2) + (3) + Figure 1.1: Forces acting on two approaching atoms: (1) repulsion between electrons, (2) attraction between protons and electrons and (3) repulsion between protons 1 repulsive force... repulsive effects are balanced, and the energy of the system is at its minimum (point X) It is at this point, when the energy is at a minimum, that bonding takes place 4 CHAPTER 1 ATOMIC COMBINATIONS - GRADE 11 1.3 The distance marked ’P’ is the bond length, i.e the distance between the nuclei of the atoms when they bond ’Q’ represents the bond energy i.e the amount of energy that must be added to the system . . . . . . . . . . . . . 110 7 Energy Changes In Chemical Reactions - Grade 11 113 7.1 What causes the energy changes in chemical reactions? . . . . . . . . . . . . . . 113 7.2 Exothermic and endothermic. . . 113 7.3 The heat of reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 7.4 Examples of endothermic and exothermic reactions . . . . . . . . . . . . . . . . 117 7.5. . . . . . 179 II Physics 183 11 Vectors 185 11. 1 Introducti on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 viii CONTENTS CONTENTS 11. 2 Scalars and Vectors . .