Physical Chemistry: Understanding our Chemical World

Physical Chemistry Understanding our Chemical World......Page 3
Contents......Page 7
Preface......Page 17
Etymological introduction......Page 21
List of symbols......Page 25
Powers of ten: standard prefixes......Page 31
Why do we warm ourselves by a radiator?......Page 35
Are these two colours complementary?......Page 36
Does my radio get louder if I vary the volume control?......Page 37
Why does the mercury in a barometer go up when the air pressure increases?......Page 39
Why does a radiator feel hot to the touch when ‘on’, and cold when ‘off’?......Page 41
What is temperature?......Page 43
How long is a piece of string?......Page 48
How fast is ‘greased lightning’?......Page 49
Why is the SI unit of mass the kilogram?......Page 51
Why is ‘the material of action so variable’?......Page 52
Why does a hot-air balloon float?......Page 54
How was the absolute zero of temperature determined?......Page 55
Why pressurize the contents of a gas canister?......Page 57
Why does thunder accompany lightning?......Page 59
How does a bubble-jet printer work?......Page 60
What causes pressure?......Page 64
Why is it unwise to incinerate an empty can of air freshener?......Page 66
Why is the room warm?......Page 67
What do we mean by ‘room temperature’?......Page 68
Why do we get warmed-through in front of a fire, rather than just our skins?......Page 69
What is ‘dry ice’?......Page 71
How is ammonia liquefied?......Page 72
Why does steam condense in a cold bathroom?......Page 73
How does a liquid-crystal display work?......Page 74
Why does dew form on a cool morning?......Page 76
How is the three-dimensional structure maintained within the DNA double helix?......Page 78
How do we make liquid nitrogen?......Page 81
Why is petrol a liquid at room temperature but butane is a gas?......Page 83
How does mist form?......Page 84
How do we liquefy petroleum gas?......Page 86
Why is the molar volume of a gas not zero at 0 K?......Page 88
Why does a bicycle tyre get hot when inflated?......Page 93
How does a fridge cooler work?......Page 94
Why does steam warm up a cappuccino coffee?......Page 95
Why does land become more fertile after a thunderstorm?......Page 97
Why does a satellite need an inert coating?......Page 98
Why does water have the formula H(2)O?......Page 100
Why is petroleum gel so soft?......Page 101
Why heat a neon lamp before it will generate light?......Page 103
Why does lightning conduct through air?......Page 106
Why is argon gas inert?......Page 108
Why is silver iodide yellow?......Page 109
Why does the mouth get cold when eating ice cream?......Page 111
Why is skin scalded by steam?......Page 113
Why do we sweat?......Page 115
Why do we still feel hot while sweating on a humid beach?......Page 117
Why is the water at the top of a waterfall cooler than the water at its base?......Page 119
Why is it such hard work pumping up a bicycle tyre?......Page 120
Why does a sausage become warm when placed in an oven?......Page 121
Why, when letting down a bicycle tyre, is the expelled air so cold?......Page 122
Can a tyre be inflated without a rise in temperature?......Page 123
How fast does the air in an oven warm up?......Page 124
Why does water boil more quickly in a kettle than in a pan on a stove?......Page 125
Why does a match emit heat when lit?......Page 128
Why does it always take 4 min to boil an egg properly?......Page 129
Why does a watched pot always take so long to boil?......Page 132
How does a whistling kettle work?......Page 133
How much energy do we require during a distillation?......Page 136
Why does the enthalpy of melting ice decrease as the temperature decreases?......Page 138
Why does water take longer to heat in a pressure cooker than in an open pan?......Page 140
Why does the temperature change during a reaction?......Page 141
Are diamonds forever?......Page 143
Why do we burn fuel when cold?......Page 145
Why does butane burn with a hotter flame than methane?......Page 148
How do we make ‘industrial alcohol’?......Page 152
How does an ‘anti-smoking pipe’ work?......Page 154
Why does dissolving a salt in water liberate heat?......Page 157
Why does our mouth feel cold after eating peppermint?......Page 159
How does a camper’s ‘emergency heat stick’ work?......Page 161
Why does the colour spread when placing a drop of dye in a saucer of clean water?......Page 163
When we spill a bowl of sugar, why do the grains go everywhere and cause such a mess?......Page 164
Why, when one end of the bath is hot and the other cold, do the temperatures equalize?......Page 165
Why does a room containing oranges acquire their aroma?......Page 167
Why do damp clothes become dry when hung outside?......Page 168
Why does crystallization of a solute occur?......Page 171
Why does the jam of a jam tart burn more than does the pastry?......Page 173
How does a reflux condenser work?......Page 178
How much energy is needed?......Page 182
Why does a vacuum ‘suck’?......Page 185
Why do we sneeze?......Page 186
How does a laboratory water pump work?......Page 187
Why is a ‘weak’ acid weak?......Page 190
Why does the pH of the weak acid remain constant?......Page 192
Why does the voltage of a battery decrease to zero?......Page 193
Why does the concentration of product stop changing?......Page 196
Why do chicken eggs have thinner shells in the summer?......Page 199
Why does egg white denature when cooked but remain liquid at room temperature?......Page 200
At what temperature will the egg start to denature?......Page 204
Why does recrystallization work?......Page 205
Why does an ice cube melt in the mouth?......Page 211
Why does water placed in a freezer become ice?......Page 215
Why was Napoleon’s Russian campaign such a disaster?......Page 216
How is the ‘Smoke’ in horror films made?......Page 218
How does freeze-drying work?......Page 219
How does a rotary evaporator work?......Page 222
How is coffee decaffeinated?......Page 223
Why is ice so slippery?......Page 226
What is ‘black ice’?......Page 227
Why does deflating the tyres on a car improve its road-holding on ice?......Page 232
Why does a pressure cooker work?......Page 233
Why does a fizzy drink lose its fizz and go flat?......Page 239
How does a separating funnel work?......Page 241
Why is an ice cube only misty at its centre?......Page 242
How does recrystallization work?......Page 243
Why are some eggshells brown and some white?......Page 245
Why does a mixed-melting-point determination work?......Page 246
How did the Victorians make ice cream?......Page 250
Why boil vegetables in salted water?......Page 251
Why does the ice on a path melt when sprinkled with salt?......Page 252
Why does petrol sometimes have a strong smell and sometimes not?......Page 255
How do anaesthetics work?......Page 256
Why does green petrol smell different from leaded petrol?......Page 258
Why do some brands of ‘green’ petrol smell different from others?......Page 259
How are essential oils for aromatherapy extracted from plants?......Page 263
Why does vinegar taste sour?......Page 267
Why is it dangerous to allow water near an electrical appliance, if water is an insulator?......Page 269
Why is bottled water ‘neutral’?......Page 270
What is ‘acid rain’?......Page 271
Why does splashing the hands with sodium hydroxide solution make them feel ‘soapy’?......Page 273
Why is aqueous ammonia alkaline?......Page 274
Why is there no vinegar in crisps of salt and vinegar flavour?......Page 275
How did soldiers avoid chlorine gas poisoning at the Second Battle of Ypres?......Page 276
Why do steps made of limestone sometimes feel slippery?......Page 278
Why is the acid in a car battery more corrosive than vinegar?......Page 279
Why do equimolar solutions of sulphuric acid and nitric acid have different pHs?......Page 284
What do we mean when we say blood plasma has a ‘pH of 7.4’?......Page 285
Why is a nettle sting more painful than a burn from ethanoic acid?......Page 287
Why is ‘carbolic acid’ not in fact an acid?......Page 288
Why does carbonic acid behave as a mono-protic acid?......Page 293
Why is an organic acid such as trichloroethanoic acid so strong?......Page 294
Why does a dock leaf bring relief after a nettle sting?......Page 295
How do indigestion tablets work?......Page 296
Why are some lakes more acidic than others?......Page 301
How do we make a ‘constant-pH solution’?......Page 304
What is ‘the litmus test’?......Page 307
Why do some hydrangea bushes look red and others blue?......Page 308
Why does phenolphthalein indicator not turn red until pH 8.2?......Page 310
Why does putting aluminium foil in the mouth cause pain?......Page 313
Why does an electric cattle prod cause pain?......Page 315
What is the simplest way to clean a tarnished silver spoon?......Page 316
Why power a car with a heavy-duty battery yet use a small battery in a watch?......Page 317
How is coloured (‘anodized’) aluminium produced?......Page 319
How do we prevent the corrosion of an oil rig?......Page 320
What is a battery?......Page 322
Why do hydrogen fuel cells sometimes ‘dry up’?......Page 323
Why bother to draw cells?......Page 325
Why do digital watches lose time in the winter?......Page 327
Why is a battery’s potential not constant?......Page 328
What is a ‘standard cell’?......Page 329
Why aren’t electrodes made from wood?......Page 334
Why is electricity more dangerous in wet weather?......Page 336
Why are the voltages of watch and car batteries different?......Page 337
How do ‘electrochromic’ car mirrors work?......Page 339
Why does a potential form at an electrode?......Page 340
Why does the smell of gravy become less intense after adding salt to it?......Page 342
Why add alcohol to eau de Cologne?......Page 343
Why does the cell emf alter after adding LiCl?......Page 346
Why does adding NaCl to a cell alter the emf, but adding tonic water doesn’t?......Page 348
Why does MgCl(2) cause a greater decrease in perceived concentration than KCl?......Page 349
Why is calcium better than table salt at stopping soap lathering?......Page 350
Why does the solubility of AgCl change after adding MgSO(4)?......Page 352
Why does sodium react with water yet copper doesn’t?......Page 355
Why does a torch battery eventually ‘go flat’?......Page 359
Why does E(AgCl,Ag) change after immersing an SSCE in a solution of salt?......Page 360
Why ‘earth’ a plug?......Page 362
Why does steel rust fast while iron is more passive?......Page 367
How do pH electrodes work?......Page 370
How do nerve cells work?......Page 373
What is a ‘salt bridge’?......Page 376
How does an electric eel produce a current?......Page 377
What is the earliest known battery?......Page 379
Why does a ‘strong’ bleach clean faster than a weaker one does?......Page 383
Why does the bleaching reaction eventually stop?......Page 385
Why does bleach work faster on some greases than on others?......Page 388
Why do copper ions amminate so slowly?......Page 390
How fast is the reaction that depletes the ozone layer?......Page 392
Why is it more difficult to breathe when up a mountain than at ground level?......Page 393
Why does a full tank of petrol allow a car to travel over a constant distance?......Page 395
Why do we add a drop of bromine water to a solution of an alkene?......Page 396
When magnesium dissolves in aqueous acid, why does the amount of fizzing decrease with time?......Page 398
Why do some photographs develop so slowly?......Page 402
Why do we often refer to a ‘half-life’ when speaking about radioactivity?......Page 412
How was the Turin Shroud ‘carbon dated’?......Page 416
How old is Ötzi the iceman?......Page 419
Why does the metabolism of a hormone not cause a large chemical change in the body?......Page 421
Why do we not see radicals forming in the skin while sunbathing?......Page 422
Why is arsenic poisonous?......Page 427
Why is the extent of Walden inversion smaller when a secondary alkyl halide reacts than with a primary halide?......Page 428
Why does ‘standing’ a bottle of wine cause it to smell and taste better?......Page 431
Why fit a catalytic converter to a car exhaust?......Page 433
Why do some people not burn when sunbathing?......Page 434
How do Reactolite® sunglasses work?......Page 437
Why store food in a fridge?......Page 442
Why do the chemical reactions involved in cooking require heating?......Page 443
Why does a reaction speed up at higher temperature?......Page 445
Why does the body become hotter when ill, and get ‘a temperature’ ?......Page 449
Why are the rates of some reactions insensitive to temperature?......Page 450
What are catalytic converters?......Page 454
Why is ink coloured?......Page 457
Why do neon streetlights glow?......Page 458
Why do we get hot when lying in the sun?......Page 459
Why is red wine so red?......Page 460
Why are some paints red, some blue and others black?......Page 461
Why can’t we see infrared light with our eyes?......Page 463
How does a dimmer switch work?......Page 467
Why does UV-b cause sunburn yet UV-a does not?......Page 468
How does a suntan protect against sunlight?......Page 470
How does sun cream block sunlight?......Page 473
Why does a glass of apple juice appear darker when viewed against a white card?......Page 476
Why are some paints darker than others?......Page 478
What is ink?......Page 479
Why do radical reactions usually require UV light?......Page 480
Why does photolysis require a powerful lamp?......Page 486
Why are spectroscopic bands not sharp?......Page 487
Why does hydrogen look pink in a glow discharge?......Page 489
Why do surfaces exposed to the sun get so dusty?......Page 491
Why is microwave radiation invisible to the eye?......Page 492
Why is the permanganate ion so intensely coloured?......Page 493
Why is chlorophyll green?......Page 495
What is gold-free gold paint made of?......Page 496
What causes the blue colour of sapphire?......Page 497
Why do we get hot while lying in the sun?......Page 498
What is an infrared spectrum?......Page 501
Why does food get hot in a microwave oven?......Page 503
Are mobile phones a risk to health?......Page 505
How are X-rays made?......Page 506
Why does metal glow when hot?......Page 507
Why is a quartz–halogen bulb so bright?......Page 508
Why do TV screens emit light?......Page 510
Why do some rotting fish glow in the dark?......Page 512
How do ‘see in the dark’ watch hands work?......Page 513
How do neon lights work?......Page 514
How does a sodium lamp work?......Page 515
How do ‘fluorescent strip lights’ work?......Page 516
Why is the mediterranean sea blue?......Page 517
Do old-master paintings have a ‘fingerprint’?......Page 519
Why is steam formed when ironing a line-dried shirt?......Page 521
Why does the intensity of a curry stain vary so much?......Page 523
Why is it difficult to remove a curry stain?......Page 526
Why is iron the catalyst in the Haber process?......Page 528
Why is it easier to remove a layer of curry sauce than to remove a curry stain?......Page 530
How does water condense onto glass?......Page 531
How does bleach remove a dye stain?......Page 532
How much beetroot juice does the stain on the plate contain?......Page 533
Why do we see a ‘cloud’ of steam when ironing a shirt?......Page 537
Why is milk cloudy?......Page 538
What is an ‘aerosol’ spray?......Page 539
What is ‘emulsion paint’?......Page 540
Why does oil not mix with water?......Page 542
How are cream and butter made?......Page 543
How is ‘clarified butter’ made?......Page 544
Why does hand cream lose its milky appearance during hand rubbing?......Page 545
Why does orange juice cause milk to curdle?......Page 546
How are colloidal particles removed from waste water?......Page 547
Why does soapy water sometimes look milky?......Page 548
What is soap?......Page 551
Why do soaps dissolve grease?......Page 552
Why is old washing-up water oily when cold but not when hot?......Page 553
Why does soap generate bubbles?......Page 555
Why does detergent form bubbles?......Page 556
Answers to SAQs......Page 559
Bibliography......Page 567
Index......Page 599