Unit KNOWLEDGE AREA MATTER AND MATERIAL 13 Unit 1 Unit 2 INDEX Page ATOMIC BONDS: MOLECULAR STRUCTURE 13 1.1 Chemical bonds 14 1.2 Bonding models 14 1.3 Valence electrons 16 1.4 Valency 16 1.5 Lewis structure 16 Activity 1 17 1.6 Formation of bonds 17 1.7 Single covalent bonds 18 1.8 Molecules with multiple bonds 19 1.9 Dative covalent bond 22 Exercise 1 23 1.10 Valence Shell Electron Pair Repulsion theory (VSEPR) and molecular shapes 24 Activity 2 25 Practical activity 1 28 Exercise 2 29 1.11 Electronegativity 30 Activity 3 34 Exercise 3 36 1.12 Forces between atoms 37 1.13 Electrical potential energy changes in the formation of a molecule 38 1.14 Bond energy and length 39 Exercise 4 41 Summary of Unit 1 43 Mind maps of Unit 1 45 INTERMOLECULAR FORCES (BETWEEN MOLECULES) 49 2.1 Types of intermolecular forces 50 2.1.1 Ion-dipole forces 51 2.1.2 Ion-induced dipole forces 52 2.1.3 Dipole-dipole forces 53 2.1.4 Dipole-induced dipole forces 54 2.1.5 Induced dipole force (dispersion or London forces) 54 2.1.6 Hydrogen bonds 55 2.2 Difference between intermolecular forces and interatomic forces 56 Exercise 5 57 2.3 The influence of intermolecular forces 59 2.3.1 State of molecules 59 2.3.2 Size of molecules 59 2.3.3 Density 60 2.3.4 Boiling point and melting point 60 2.3.5 Viscosity 61 Activity 4 61 2.3.6 Thermal expansion 64
2.3.7 Thermal conductors 64 Experiment 1 64 Experiment 2 66 Experiment 3 68 Experiment 4 69 Experiment 5 70 Exercise 6 71 2.4 Chemistry of water 73 2.4.1 Microscopic structure of water 73 Activity 5 75 2.4.2 Properties of water 75 Experiment 6 77 Experiment 7 78 Experiment 8 79 Exercise 7 80 Summary of Unit 2 82 Mind maps of Unit 2 87 Unit 3 IDEAL GASES AND THERMAL PROPERTIES 89 3.1 Movement of particles 89 3.2 Average kinetic energy of gas molecules and temperature 90 3.3 The ideal gas model 90 Exercise 8 92 3.4 The relationship between volume and pressure of a gas 95 Experiment 9 95 Exercise 9 100 3.5 Relationship between volume and temperature of a gas 103 Experiment 10 103 3.6 Relationship between temperature and pressure of a gas (constant volume of gas) 106 3.7 Kelvin temperature scale 107 Exercise 10 109 3.8 Relationship between pressure, volume and temperature of a gas 110 Exercise 11 111 3.9 The ideal gas equation 113 Exercise 12 114 Summary of Unit 3 115 Mind maps of Unit 3 117 Question paper 119 KNOWLEDGE AREA CHEMICAL CHANGE 125 Unit 1 QUANTITATIVE ASPECTS OF CHEMICAL CHANGE: STOICHIOMETRY 125 1.1 Mole concept 126 1.2 Molecular atomic mass (A), molar molecular mass and molar formula mass (M) 127 Exercise 13 128 1.3 Relationship between moles, mass and molar mass 130 Exercise 14 131 1.4 Molar gas volume 133 1.4.1 Avogadro s law 133
1.4.2 Molar volume in balanced chemical equations 134 Exercise 15 135 1.5 Concentration of solutions 136 1.5.1 Calculating the concentration of a solution 136 1.5.2 Preparation of a standard solution 139 Practical demonstration 139 1.5.3 Diluting solutions 140 Exercise 16 141 1.6 Percentage composition of compounds 143 1.6.1 Calculations 143 1.6.2 Determination by practical quantitative methods 145 Exercise 17 147 1.7 Empirical formula 148 Exercise 18 149 1.8 Molecular formula 150 Exercise 19 151 1.9 Stoichiometric calculations 152 1.9.1 Calculations based on balanced equations 152 1.9.2 Limiting reactants 158 1.9.3 Mass of precipitate formed during precipitation reactions 161 1.9.4 Percentage yield 161 1.10 Applications of exothermic reactions that produce large amounts of gas 162 Experiment 11 163 Exercise 20 167 Summary of Unit 1 171 Mind maps of Unit 1 175 Unit 2 ENERGY AND CHEMICAL CHANGE 177 2.1 Introduction 177 2.2 Breaking and forming of bonds during a chemical reaction 178 2.3 Application of exothermic and endothermic reactions 180 Experiment 12 182 Experiment 13 184 2.4 Bond energy 186 Exercise 21 187 2.5 Activation energy and activated complex 190 2.5.1 Energy profiles for exothermic and endothermic reactions 192 2.5.2 Catalysts 192 Experiment 14 194 Exercise 22 195 Summary of Unit 2 198 Mind maps of Unit 2 200 Unit 3 ACID-BASE REACTIONS 201 3.1 Acids 201 3.2 Bases 203 3.3 Strong and weak acids and bases 204 3.4 Concentrated and dilute acids and bases 205 3.5 Acid-base reactions 205 Exercise 23 207
3.6 Ampholytes 210 3.7 Reactions of acids 210 3.7.1 Acid-metal carbonate reactions 211 3.7.2 Acid-metal oxide reactions 211 3.7.3 Acid-metal hydroxide reactions 211 3.7.4 Acid-base reactions: applications 214 3.8 Indicators 214 Practical activity 2 215 Experiment 15 215 Experiment 16 216 Experiment 17 218 Exercise 24 219 Summary of Unit 3 222 Mind maps of Unit 3 223 Unit 4 REDOX REACTIONS 225 4.1 Oxidation numbers 226 4.2 Reactions 228 4.2.1 Displacement reactions 228 Experiment 18 228 4.2.2 Synthesis reactions 230 Experiment 19 230 4.2.3 Decomposition reactions 233 Experiment 20 233 4.2.4 Reducing action 234 Experiment 21 234 4.2.5 Oxidising effect 236 Experiment 22 236 Exercise 25 237 Summary of Unit 4 241 Mind maps of Unit 4 242 Question paper 243 KNOWLEDGE AREA CHEMICAL SYSTEMS 251 Unit 1 THE DEVELOPMENT OF MINING 251 1 Introduction 251 1.1 People through the ages 251 1.2 Mineral sources in South Africa 253 Exercise 26 256 Summary: of Unit 1 257 Unit 2 MINING AND MINERAL PROCESSING 258 A GOLD 259 2.1 Gold in South Africa 259 2.1.1 Reasons for mining gold 259 2.1.2 Locations 260 2.1.3 Gold mining and processing 260 2.1.4 Gold mining and the environment 261 Exercise 27 262 2.1.5 Ancient mining methods 265 Case study: Mapungubwe: South Africa s lost city of gold 265
B IRON 268 2.2 Iron in South Africa 268 2.2.1 Reasons for mining iron 268 2.2.2 Why South Africa exports iron ore 269 2.2.3 Locations 269 2.2.4 Iron ore mining and processing 269 Experiment 23 271 Experiment 24 272 2.2.5 Iron mining and the environment 273 2.2.6 Processing of iron 274 Experiment 25 274 Exercise 28 276 C PHOSPHATES 279 2.3 Phosphates in South Africa 279 2.3.1 Reasons for mining phosphates 279 2.3.2 The most important mining activities in South 279 Africa 2.3.3 Mining and processing of phosphate rock 279 2.3.4 Uses 281 2.3.5 The impact of phosphate mining on the environment 281 Exercise 29 282 Project 283 Summary of Unit 2 284 Mind maps of Unit 2 287 Unit 3 GLOBAL WARMING 293 3.1 Increasing human population and global warming 293 3.2 Burning of fossil fuels 294 3.3 What is global warming? 295 3.4 Consequences of global warming 295 Exercise 30 295 Summary of Unit 3 296 Mind maps of Unit 3 297 Question paper 298 Information sheets 309 Work cited 311