Introduction. A1.1 (a) Shell number and number of subshells 1. A1.1 (b) Orbitals 2. A1.1 (c ) Orbital shapes (s, p & d) 2

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1 Preface Table of Contents Introduction i A1.1 (a) Shell number and number of subshells 1 A1.1 (b) Orbitals 2 A1.1 (c ) Orbital shapes (s, p & d) 2 A1.1 (d) Relative energies of s,p,d,f sub-shells 4 A 1.1 (e) Electron spin and spin pairing 4 A 1.1 (f) Aufbau principle 4 A1.1 (g) Ground state electron configurations 5 A1.1 (h) Electrons-in-a-box 8 A1.1 (i) Period 3 trends 9 A1.1 (j) Relationship between Group number and successive ionisation energies 13 A1.2 (a) Dot and cross diagrams 17 A1.2 (b) Molecular orbitals 21 A1.2 (c) Covalent bond strength 22 A1.2 (d) Sigma and pi bonds 22 A1.2 (e) Strengths of σ and π bonds 22 A1.2 (f) Bond order 23 A1.2 (g) VSEPR theory 24 A1.2 (h) Changes in geometry and bond angles 30 A1.2 (i) Electronegativity and bond polarity 30 A1.2 (j) Van der Waals forces 33 A1.2 (k) Hydrogen bonding 36 A1.2 (l) Protein structure 37 A1.3 (a) Energy changes 39 A1.3 (b) Equation 1 43 A1.3 (c) Hess s Law and the First Law of Thermodynamics 45 vii

2 Pre-U Chemistry A1.3 (d) Calculating Enthalpy Changes 1 48 A1.3 (e) Calculating lattice enthalpies 50 A1.3 (f) Understanding catalysts 52 A1.3 (g) Enthalpy profile diagrams 54 A1.3 (h) Boltzmann distribution 54 B1.4 (a) What is entropy? 57 B1.4 (b) Total entropy change ( S total ) 60 B1.4 (c) Calculating S 60 B1.4 (d) Entropy change of the surroundings 62 B1.4 (e) Second Law of Thermodynamics 63 B1.4 (f) Gibbs free energy and the Gibbs energy equation 64 B1.4 (g) Gibbs Energy and the Equilibrium constant (K) 66 B1.5 (a) Le Chatelier s principle 70 B1.5 (b) Weak acids and weak alkalis 74 B1.5 (c) Equilibrium constant expressions (K c ) 79 B1.5 (d) Equilibrium constant expressions (K p, K sp, K a & K w ) 80 B1.5 (e) Equilibrium constant calculations 83 B1.5 (f) ph and pk a 88 B1.5 (g) Acid base titrations and indicators 91 B1.5 (h) Buffer solutions 94 B1.5 (i) Quantitative electrolysis 97 B1.5 (j) Redox and oxidation number 99 B1.5 (k) Standard electrode potential and the standard hydrogen electrode 101 B1.5 (l) Measuring standard electrode potentials (practical) 102 B1.5 (m) Calculating standard cell potentials (theory) 104 B1.5 (n) Linking standard cell potential and Gibbs energy change 106 B1.5 (o) Electrochemical cells 107 B1.5 (p) Variation of cell potentials (equilibrium and non-standard conditions) 109 viii

3 Preface B1.5 (q) Hydrogen/oxygen fuel cell 110 B1.6 (a) Kinetic theory applied to an ideal gas 113 B1.6 (b) Boyle s law, Charles s law and the ideal gas equation 115 B1.6 (c) Boltzmann distribution 119 B1.6 (d) Rate constant and the Arrhenius equation 119 B1.6 (e) Homogeneous and heterogeneous catalysis 122 B1.6 (f) Rate equations and orders 125 B1.6 (g) Rate-determining step and mechanism 127 B1.6 (h) Mechanisms and rate equations 128 B1.6 (i) Deducing rate equations 129 B1.6 (j) First order reactions and half-life 133 B1.7 (a) Chemistry an evidence-based subject 138 B1.7 (b) Theories, models, facts & definitions 139 B1.7 (c) Breakdown of the ideal gas model 140 B1.7 (d) Limitations of the ionic model 140 A2.1 (a) Regions of the Periodic Table 143 A2.1 (b) Structures of the Elements 144 A2.1 (c) Period 3 trends in terms of structure and bonding 145 A2.1(d) Van Arkel diagrams 146 A2.1 (e) Oxidation number 151 A2.1 (f) Period 3 elements reactivity with oxygen 154 A2.1 (f) Period 3 elements reactivity with water 156 A2.1 (g) Period 3 oxides reactivity with water 157 A2.1 (h) Period 3 chlorides and water 158 A2.1 (i) Mineral oxides 161 A2.2 (a) Thermal decomposition of carbonates 164 A2.2 (b) Structures of nitrogen and white phosphorus 165 A2.2 (c) Unreactivity of nitrogen 166 ix

4 Pre-U Chemistry A2.2 (d) Acid-base behaviour of ammonia and the ammonium ion 167 A2.2 (e) Allotropes of oxygen 169 A2.2 (f) Redox properties of hydrogen peroxide 170 A2.2 (g) Removing sulfur oxides (fuels and power stations) 174 A2.2 (h) Properties and reactions of sulfuric acid 175 A2.2 (i) Trends in physical and chemical properties of the halogens 178 A2.2 (j) Halogens bond enthalpies 178 A2.2 (k) Trend in acidity of the hydrogen halides 179 A2.2 (l) Reaction of halides with concentrated H 2 SO A2.2 (m) Reaction of iodine with sodium thiosulfate 181 A2.2 (n) Reactions of the halogens with cold NaOH (aq) 183 A2.2 (o) Fluorine: anomalous reactivity & high oxidation state fluorides 184 B2.3 (a) Allotropes of carbon 188 B2.3 (b) Transition from non-metal to metalloid to metal 191 B2.3 (c) Lead chemistry (mainly +2 oxidation state) 193 B2.3 (d) Transition from covalent oxides to ionic oxides 196 B2.3 (e) Bonding in divalent and tetravalent oxides 198 B2.4 (a) Comparing properties of transition elements and the s-block 202 B2.4 (b) Variation of properties across the series 204 B2.4 (c) Characteristic properties of transition elements 205 B2.4 (d) Octahedral, tetrahedral and square planar complexes 210 B2.4 (e) Geometric and Optical isomerism in complexes 211 B2.4 (f) d-orbital splitting in transition metal complexes 215 B2.4 (g) Origin of colour in transition metal complexes 217 B2.4 (h) Ligand exchange and observed colour changes 221 B2.4 (i) Redox chemistry Fe 3+ /Fe 2+ ; MnO 4- /Mn ; Cr 2 O 7 /Cr 3+ ; Cu 2+ /Cu B2.4 (j) Biological role of three important iron complexes 227 B2.4 (k) Stability of Co 2+ and Co 3+ with different ligands 228 x

5 Preface B2.5 (a) Crystal structures of metals 232 B2.5 (b) Unit cells 235 B2.5 (c) Lattices (geometry and coordination number) 238 B2.5 (d) Holes in close-packed structures 240 B2.5 (e) Lattice structures of sodium chloride and calcium fluoride 242 B2.5 (f) Determination of lattice energies 243 A3.1 (a) Tetrahedral carbon 246 A3.1 (b) Skeletal formula 247 A3.1 (c) Molecular formulae from structures 249 A3.1 (d) Structural isomerism 250 A3.1 (d) Geometric isomerism 252 A3.1 (e) Optical isomerism 253 A3.1 (f) 3D Structures 255 A3.1 (g) Nomenclature 257 A3.1 (h) Terms and Reactions 260 A3.2 (a) Inactivity of C-H & C-C bonds 265 A3.2 (b) Heteroatoms increase reactivity 266 A3.2 (c) Functional group recognition and naming simple molecules 268 A3.2 (d) Functional group level (FGL) 279 A3.2 (e) FGL of unfamiliar examples and changes in FGL 280 A3.2 (f) Choice of reagents guided by FGL 283 A3.2 (g) Common examples within FGL 285 A3.2 (h) Unstable groups 286 A3.3 (a) Hydrolysis within alcohol level 292 A3.3 (b) Synthesising functional groups with FGL = A3.3 (c) Halogenoalkanes reacting with cyanide 295 A3.3 (d) Oxidation of alcohols 296 A3.4 (a) Lower functional group level reactions Carbonyl level 304 xi

6 Pre-U Chemistry A3.3 (b) Addition of bisulfite 304 A3.4 (c) Oxidation of aldehydes 305 A3.4 (d) Addition to carbonyls 307 A3.5 (a) π-bonds in double bonds (C=C and C=O) 311 A3.5 (b) Addition Reactions to C=C 312 A3.5 (c) Addition polymerisation 314 A3.5 (d) Elimination from alcohols to make alkenes 317 A3.5 (e) Elimination from alkyl halides to make alkenes 318 A3.6 (a) Atom economy 323 A3.6 (b) Chemicals and the Environment 325 B3.7 (a) Hydrolysis (moving within the level) 332 B3.7 (b) Substitution (moving within the level) 334 B3.7 (c) Condensation polymerisation 337 B3.7 (d) Reduction with metallic hydrides (moving down a level) 344 B3.8 (a) Hydrolysis (moving within the Carbon Dioxide level) 350 B3.8 (b) Carboxylic acids from Grignard reagents 352 B3.9 (a) S N 1 and S N 2 mechanisms 356 B3.9 (b) Transition states and intermediates 358 B3.9 (c) Inversion of configuration (S N 2) and racemisation (S N 1) 360 B3.9 (d) Effect of type of halogenoalkanes and C-X bond strength on mechanisms 362 B3.9 (e) Electrophilic addition mechanism 363 B3.9 (f) Stability of carbocation (Markovnikov s Rule) 364 B3.9 (g) Evidence for carbocation intermediates 366 B3.9 (h) Nucleophilic addition mechanism 367 B3.9 (i) Addition of HCN to unsymmetrical carbonyls (racemic products) 368 B3.10 (a) Aromatic stability of benzene 370 B3.10 (b) Electrophilic substitution of benzene 371 B3.10 (c) Benzene rings and the Inductive Effect 373 xii

7 Preface B3.10 (d) Aryl amines from nitro arenes 377 B3.11 (a) Relative acidities of water, alcohols and phenols 381 B3.11 (b) Relative basicities of ammonia, aliphatic and aromatic amines 383 B3.11 (c) Acidity of substituted carboxylic acids 385 B3.11 (d) Reaction of α-amino acids with acids and alkalis 387 B3.12 (a) Cahn-Ingold-Prelog priority rules 390 B3.12 (b) Rotating polarised light 392 B3.12 (c) R/S and +/ assignments 393 B3.12 (d) Molecules with two chiral centres 394 A4.1 (a) Qualitative analysis 399 A4.1 (b) Empirical and molecular formulae 406 A4.1 (c) Volumetric analysis 408 A4.1 (d) Gravimetric analysis 413 A4.1 (e) Gas volumes 417 A4.2 (a) Time of flight mass spectrometry 420 A4.2 (b) Interpreting spectra (molecular ions and fragments) 422 A4.2 (c) Isotopes and mass spectrometry 425 A4.3 (a) Atomic absorption and emission 430 A4.3 (b) Plank s Equation E = hf 431 A4.3 (c) Line spectrum of hydrogen (qualitative) 433 A4.4 (a) Resonant bond vibrations 438 A4.4 (b) Stretching frequencies (bond strength and atomic masses) 439 A4.4 (c) Stretching frequencies (bonds to H) 441 A4.4 (d) Interpreting simple spectra (alcohols & carboxylic acids) 443 A4.5 (a) Number of peaks in a carbon-13 NMR spectrum 448 A4.5 (b) Chemical shift values 450 A4.5 (c) Interpreting decoupled carbon-13 NMR spectra 450 B4.6 (a) The NMR Process 456 xiii

8 Pre-U Chemistry B4.6 (b) Origin of the chemical shift scale (δ) 458 B4.6 (c) Interpreting spin-½ NMR spectra 459 B4.6 (d) Pascal s triangle and the n+1 rule 464 Index 468 xiv