Figure 3 If the 6.02 x 10 23 atoms in 12 g ofcarbon were turned into marbles, the marblescould cover Great Britain to a depth of 1500 km!

Figure 3 The mass spectrometer.

Figure 3 The mass spectrometer.

Figure 7 Variation of first ionisation enthalpywith atomic number for elements with atomicnumbers 1 to 56.

Figure 8 Successive ionisation enthalpies for aluminium.

sample inlet

electron gun

magnetic field

(at right angles

to paper)

ion detector

ionisation chamber

accelerating electric field

heavy particles

intermediate

particles

lighter particles

pump maintains

low pressure

He

Li

Ne

Na

Ar

K

Kr

Rb

Xe

Cs

2500

2000

1500

1000

500

Atomic number

50403010 200Io

nis

ation e

nth

alp

y/

kJ m

ol–

1

Ionisation1st 2nd 3rd 4th 5th 6th 7th 8th

20 000

10 000

0Ionis

ation e

nth

alp

y/k

J m

ol–

1

Figure 9 Successive ionisation enthalpies for phosphorus.

Energy

Shell Sub-shell

n = 4

n = 3

n = 2

n = 1

4443433

22

1

fdpdsps

sp

s

Figure 10 Energies of electron sub-shells from n = 1 to n = 4 in a typical many-electron atom.The energy of a sub-shell is not fixed, but falls asthe charge on the nucleus increases as you gofrom one element to the next in the PeriodicTable. The order shown in the diagram is correctfor the elements in Period 3 and up to nickel inPeriod 4. After nickel the 3d sub-shell has lowerenergy than 4s.

1s

2s

3s

3p

2p

3d

Energy

Figure 13 Arrangement of electrons in atomicorbitals in a ground state sodium atom.

Ionisation1st 2nd 3rd 4th 5th 6th 7th 8th

20 000

10 000

0Ion

isa

tio

n e

nth

alp

y/k

J m

ol–

1

30 000

Figu

re 1

4 Bu

ildin

g up

the

Peri

odic

Tab

le.

sym

bo

l

ele

ctr

onic

configura

tion

(oute

r sub-s

hell(

s)

only

)

ato

mic

num

ber

KE

Y O8

2p

4

Actinid

es

Lanth

anid

es

Pa

Np

Pr

Th

U

Ce

Nd

Pm

Ac

Fr

Ra

58

59

60

61

90

91

92

93

87

88

89

4 5 6 7

3d

14s

23d

34s

2

4d

15s

24d

35s

2

5d

16s

25d

36s

2

3d

24s

23d

54s

1

4d

25s

24d

55s

2

5d

26s

25d

46s

2

4s

1

5s

1

6s

1

7s

1

4s

2

5s

2

6s

2

7s

2

4d

55s

1

3d

54s

2

5d

56s

2

3 11

19

4 12

20

37 55

38

56

23

25

21

39

57

24

41

22

40

72

43

42

73

75

74

Li

Be

Na

Mg

KC

a

Rb

Sr

Cs

Ba

LaS

c Y

Hf

Ti

Zr

TaV Nb

WCr

Mo

Re

Mn

Tc

filli

ng d

sub-s

hells

filli

ng 4

f su

b-s

he

ll

filli

ng 5

f su

b-s

he

ll

3d

64s

2

4d

75s

1

5d

66s

2

3d

74s

2

4d

85s

1

5d

76s

2

3d

84

s2

5d

96

s1

3d

104

s1

4d

105

s1

5d

106

s1

3d

104

s2

4d

105

s2

5d

106

s2

27

29

28

45

26

44

76

47

46

77

79

78

30

48

80

63

62

94

65

64

95

97

96

66

98

Am

Bk

Eu

Pu

Cm

Sm

Gd

Tb

Os

Fe

Ru

IrCo

Rh

Pt

Ni

Pd

Au

Cu

Ag

Cf

Dy

Hg

Zn

Cd

4d

105

s0

4p

1

5p

1

6p

1

4p

2

5p

2

6p

2

4p

2

6p

3

4p

4

5p

4

6p

4

4p

5

5p

5

6p

5

32

34

33

50

31

49

81

52

51

82

84

83

35

53

85

68

67

99

70

69

10

01

02

10

1

71

10

3

Fm

No

Er

Es

Md

Ho

Tm

Yb

Tl

Ga

In

Pb

Ge

Sn

Bi

As

Sb

Po

Se

Te

Lr

Lu

At

Br I

5p

3

4p

6

5p

6

6p

6

36

54

86R

n

Kr

Xe

filli

ng

p s

ub

-sh

ells

34

56

70

2p

1

3p

1

2p

2

3p

23

p3

2p

4

3p

4

2p

5

3p

5

65 1

3

87

14

16

15

9 17

Tl

B

Si

C

PN

SO

Cl

F2

p3

1s

2

2p

6

3p

6

2 10

18

Ar

He

Ne

1s

1

1

H

2s

1

3s

1

2s

2

3s

2

Period

1 2 3

filli

ng s

sub-s

hells

12

Gro

up

Figure 15 Dividing up the Periodic Table.

s block

d block

p block

metals non-metalsf block

Cl– ion

Na+ ion

‘Pool’ of delocalised

electrons

attraction

nucleus

+ +–

–

shared electrons

Figure 9 In a hydrogen molecule, the atoms areheld together because their nuclei are bothattracted to the shared electrons.

Li1.0

Be1.6

B2.0

C2.6

N3.0

O3.4

F4.0

Na0.9

Mg1.3

K0.8

Ca1.0

Rb0.8

Sr1.0

Al1.6

Si1.9

P2.2

S2.6

Cl3.2

Br3.0

I2.7

H2.2

Li1.0

Period

symbol

electronegativity

KEY

Group

2

1

1 2 3 4 5 6 7

3

4

5

Figure 2 The sodium chloride lattice, built upfrom oppositely charged sodium ions andchloride ions.

Figure 15 A model of metallic bonding.

Figure 13 Pauling electronegativity values forsome main group elements in the Periodic Table.

Figure 17 The relative sizes of atoms and ions.

Figure 18 Ions with higher charge densitiesattract more water molecules (ions are only shown in two dimensions).

Na+ ion (charge 1+, radius 0.098nm)

On average, each Na+ ion is surrounded by

5 water molecules

Mg 2+ ion (charge 2+, radius 0.078nm)

On average, each Mg 2+ ion has 15

water molecules around it

+ 2+

Figure 19 Hydrated ions are much bigger thanisolated ions.

Li+ (g)

isolated Li+ ion(radius = 0.078nm)

Li+ (aq)

hydrated Li+ ion (radius = 1.00nm)

Na+ (g)

Na+ (aq)

isolated Na+ ion(radius = 0.098nm)

Figure 36 Two isomers of alanine.

H

CHOOC NH2

CH3

H

CCOOHH2N

H3C

Figure 38 The CORN rule. Look down the H—C bond from hydrogen towards the centralcarbon atom.

COOH COOH

C

H

CORNL isomer

H2N

R

C

H

CORND isomer NH2

R

hydrated Na+ ion (radius = 0.79nm)

Li Li+

Li atom

ratom = 0.152 nm

Li+ ion

rion = 0.078 nm

Na Na+

Na atom

ratom = 0.186 nm

Na+ ion

rion = 0.098 nm

Mg Mg2+

Mg atom

ratom = 0.160 nm

Mg2+ ion

rion = 0.078 nm

F F–

F atom

ratom = 0.071 nm

F– ion

rion = 0.133 nm

O O2–

F atom

ratom = 0.073 nm

F– ion

rion = 0.132 nm

Ent

halp

y

reactants productsProgress of reaction

chemicalreactants

energy given outto surroundings∆H negative

eg CH4+2O2

productseg CO2+2H2O

Figure 1 Enthalpy level diagram for anexothermic reaction, eg burning methane:CH4 +2O

2 g CO

2 + 2H

2O.

thermometer

water

electrically heatedwire to ignite sample

air jacket

oxygen under pressure

crucible containingsample under test

stirrer

Figure 3 A bomb calorimeter for makingaccurate measurements of energy changes. Thefuel is ignited electrically and burns in theoxygen inside the pressurised vessel. Energy istransferred to the surrounding water, whosetemperature rise is measured.Note that the experiment is done at constantvolume in a closed container. Enthalpy changesare for reactions carried out at constant pressure ,so the result needs to be modified accordingly.

energy taken infrom surroundings∆H positive

chemicalreactantseg CaCO3

Ent

halp

y

reactants productsProgress of reaction

productseg CaO+CO2

Figure 2 Enthalpy level diagram for anendothermic reaction, eg decomposing calciumcarbonate: CaCO

3 g CaO + CO

2.

∆H going this way...

... is the same as ∆H going

this way

CH4(g)

CO2(g) + 2H2O(I)

C(s) + 2H2(g)

Figure 4 An enthalpy cycle for finding the enthalpychange of formation of methane, CH4 .

Ene

rgy +

breaking bonds(takes in energy)

making new bonds(gives out energy)

H

H

O O

O O

C H

O O O O

H H H

C OOO

HH

O

HH

C

H H

Figure 9 Breaking and making bonds in the reaction between methane and oxygen.

Solid Liquid Gas

particles in fixed positions particles moving aroundregular lattice pattern random arrangement

particles close together particles widely separatedvolume depends only slightly on pressure and temperature

volume depends strongly ontemperature and pressure

Figure 14 A comparison of solids, liquids andgases.

Increasing energy

each rotationallevel has its own

translational levels

each vibrationallevel has its own

rotational levels

each electroniclevel has its own

vibrational levels

ground electronicenergy level

vibrationalenergylevels

rotationalenergylevels

translationalenergylevels

Figure 15 Each electronic energylevel has within it severalvibrational, rotational andtranslational energy levels. Notethat the levels are not to scale.

‘stack’ of ‘stack’ of ‘stack’ of

ionic lattice + solvent solution

gaseous ions+

solvent

∆Hsolution

∆HLE ∆Hhyd(cation)

+∆Hhyd(anion)

Figure 21 An enthalpy cycle to show thedissolving of an ionic solid.

Figure 26 Born–Haber cycle for sodiumchloride.

NaCI(s)Na(s) + ½CI2(g)

Na+(g) + CI-(g)Na(g) + CI(g)

∆H2

∆H1

∆H3

∆H4

Figure 27 Born–Haber cycles for sodium chloride and potassium chloride.

Enthalpy/kJmol–1

Na+(g) + Cl(g)

+800

+700

+600

+500

+400

∆Hi (1)(Na)

∆HEA(1)(Cl)

Na+(g) + Cl(g)

K+(g) + Cl(g)

∆Hi (1)(K)

K+(g) + Cl(g)

K+(g) + Cl–(g)

∆HEA(1)(Cl)

+400

+200

+100

0

+300

–100

–200

–300

–400

–500

Na(g) + Cl(g)

∆Hat (Cl)

Na+(g) + 12 Cl2(g)

∆Hat (Na)

Na(s) + 12 Cl2(g)

∆Hf (NaCl)

NaCl(s)

∆HLE(NaCl)

∆Hat (Cl)

K(g) + 12 Cl2(g)

∆Hat (K)

K(s) + 12 Cl2(g)

∆Hf

(KCl) ∆HLE(KCl)

KCl(s)

Figure 27 Born–Haber cycles for sodium chloride and potassium chloride.

Enthalpy/kJmol–1

Na+(g) + Cl(g)

+800

+700

+600

+500

+400

Na+(g) + Cl(g)

K+(g) + Cl(g)

K+(g) + Cl(g)

K+(g) + Cl–(g)

+400

+200

+100

0

+300

–100

–200

–300

–400

–500

Na(g) + Cl(g)

Na+(g) + 12 Cl2(g)

Na(s) + 12 Cl2(g)

NaCl(s)

K(g) + 12 Cl2(g)

K(s) + 12 Cl2(g)

KCl(s)

Figure 2 What happens when an ionic substancesuch as sodium chloride dissolves in water.

Figure 5 Polar water molecules attract the ions ina solid lattice.

Figure 11 (a) The structure of diamond and (b)the structure of graphite.

(a) (b)

Figure 12 Imagine you are inside a diamond. Theregular network structure would repeat in alldirections – as far as the edge of the diamond.

Figure 13 The fullerenes are a recently discoveredmolecular form of carbon. (a) shows C60 , named buckminsterfullerene. It is made up of a mixture of 5-membered and 6-membered rings and looks like a football(b) is another way of presenting C60 , showing thepositions of the carbon atoms(c) shows C70 , which is shaped like a rugby ball.

(a) (b) (c)

– + –

– –

– –

– –

––

–

–

+

+ +

+ +

+ +

+

+

+

+

Solid sodium chloridea retular ionic lattice

Cl– Na+ Cl–(aq) Na+(aq) water molecule

Sodium chloridedissolved in water

δ−δ+

solid lattice

polar water molecule

hydrated ions

+

–

+

+

+ +

+ +

+ + +

+ + +

–

– –

– –

– –

– – –

δ−

δ−δ−

δ−

δ−

δ−

δ−

δ−

δ−

δ−

δ−δ−

δ−

δ−δ+

δ+

δ+δ+

δ+ δ+

δ+

δ+δ+

δ+δ+

δ+

δ+δ+

Figure 14 On heating, the molecular substance(represented by ) changes from a solid to aliquid and then to a gas. Energy must be suppliedto overcome the intermolecular forces. Note thatthe covalent bonds within the molecules remainintact.

heatm.p.

heatb.p.

Solid Liquid Gas

δ+ δ –

At some instant, more of the electroncloud happens to be at one end of themolecule than the other; moleculehas an instantaneous dipole.

Electron cloud evenly distributed; no dipole.

Cl Cl Cl Cl

Figure 15 How a dipole forms in a chlorinemolecule.

This atom is not yet polarised, but its electrons are repelled by the dipole next to it ...

Xe

This atom is instantaneouslypolarised

Xeδ+ δ – Xeδ+ δ –

... so it becomespolarised

Xeδ+ δ –

Figure 18 How an induced dipole is formed in aXe atom.

Boi

ling

poin

t/K

400

300

200

100

Period2 3 4 5

H2TeSbH3HISnH4

H2O

HF

NH3

CH4

Group 4Group 5Group 6Group 7

Figure 20 Variation in the boiling points of thehydrides of some Group 4, 5, 6 and 7 elements.

Ent

halp

y ch

ange

of

vapo

risat

ion/

kJ

mol

-1 l

40

20

0

Period2 3 4 5

H2TeSbH3HISnH4

H2O

HFNH3

CH4

Group 4Group 5Group 6Group 7

Figure 21 Variation in the enthalpy changes ofvaporisation of some Group 4, 5, 6 and 7elements.

Lone pair; concentratednegative charge

FH

Hδ+

Fδ–

Figure 23 The positively charged H atom linesup with the lone pair on an F atom.

H

HHHO

Hydrogen bond

Lone pair

O

HHO

Figure 25 The positively charged H atoms lineup with the lone pairs on the O atoms.

Key

oxygenhydrogenhydrogen bond

Figure 28 The arrangement of water moleculesin ice.

HEA T

easily broken by heating; polymer canbe moulded into new shape.

chains cannot be easily broken; polymerkeeps shape on heating.

polymer chain

cross–link

Figure 29 Thermoplastics and thermosets.

crystalline region

amorphous region

Figure 32 Crystalline and amorphous regions ofa polymer.

GIANTLATTICEgoes on

indefinitely

STRUCTURES

MOLECULARmade of groups of atoms

COVALENTMOLECULAR

COVALENTNETWORK

METALLICIONIC MACROMOLECULAR(eg polymers)

Figure 36 A summary of the structures ofsubstances.

(a) Thermoplastic: no cross–linking

HEAT

Weak forces between polymer chains

(b) Thermoset: extensive cross–linking Strong covalent bonds between polymer

Figure 3 Obtaining a line emission spectrum.

Figure 4 Obtaining a line absorptionspectrum.

electron hasbeen excitedto level 5,drops back tolevel 1

etclevel 5level 4

level 3

level 2

level 1ground

state

Lyman series

this line correspondsto electrons droppingfrom level 5 1

1

21

3

1 5

2 1 3 1 4 1

1 4

Frequency

Figure 6 How the Lyman series in theemission spectrum is related to energylevels in the H atom.

wire with sampleof element

excited atomsin hot flameemit light

slit

prism

line emission spectrum(bright lines on a blackbackground)

source ofwhite light

wire with sampleof element

cool flame:most atoms in vapour are in theirground state line absorption spectrum (black lines

on a bright coloured background)

slit

prism

Increasingenergy

Cl H

ELECTRONICENERGY

VIBRATIONALENERGY

ROTATIONALENERGY

TRANSLATIONALENERGY

Cl H

Cl H

Cl H

Cl HFigure 7 An HCl molecule has energy associatedwith different aspects of its behaviour.

Figure 16 The basic parts of a double beaminfrared spectrometer.

3000 2000 1000Wavenumber/cm –1

Tran

smitt

ance

/%

100

80

60

40

20

Figure 21 Infrared spectrum of butane.

Absorption/cm–1 Bond2970 C—H (alkane)

CH3 CH2 CH2 CH3

sample cell forsolution of sample

infrared source(electrically heatedfilament)

reference cellfor solvent only

NaCl prism(or diffraction

grating)

infrareddetector

chart recorder

3000 2000 1000Wavenumber/cm–1

Tran

smitt

ance

/%

100

80

60

40

20

Figure 23 Infrared spectrum of benzoic acid.

Absorption/cm–1 Bond3580 O−H3080 C−H (arene)1760 C=O

COHO

Figure 22 Infrared spectrum of methylbenzene.

Absorption/cm–1 Bond3050 C−H (arene)2940 C−H (alkane)

CH3

powerfulmagnet

sample

RF signal generator detector

recorder

SN

Figure 37 A simplified diagram of an n.m.r.spectrometer.

N S

N S

E2

E1

∆Ealigned againstmagnetic field

aligned withmagnetic field

N S

NS

Figure 36 The principle of n.m.r.: a smallmagnet in a strong magnetic field can have twodifferent energies.

100

80

60

40

20

3000 2000 1000

Wavenumber/cm–1

Tra

nsm

itta

nce/%

Chemical Relative Type ofshift no. protons proton0.9 3 CH31.3 4 CH2

CH3 CH2 CH2 CH2 CH2 CH3

Abs

orpt

ion

012345Chemical shift

8H6H

TMS

678910

Figure 43 N.m.r. spectrum of hexane.

Chemical Relative Type ofshift no. protons proton1.6 3 CH3

5.6 1

C C

H

CH3

H3C

H

H C C H

Figure 44 N.m.r. spectrum of trans-but-2-ene.

Abs

orpt

ion

012345Chemical shift

3H

2H

2H

1H

TMS

678910

Chemical Relative Type ofshift no. protons proton0.9 3 CH3

1.6 2

2.3 1 OH

3.6 2

CH3 CH2 CH2 OH

C CH2 C

C CH2 OFigure 45 N.m.r. spectrum of propan-1-ol.

transparent object,glass or a solution

all wavelengths ofvisible light transmitted:appears colourless

all wavelengthsof visible lightreflected:appears white

opaque object,eg a piece of chalk

Figure 52 How light behaves with transparentand opaque objects.

Chemical shift

Ab

so

rptio

n

6H

TMS2H

10 9 8 7 6 5 4 3 2 1 0

transparent object

absorbsred

transmits wavelengths correspondingto other colours: appears green

reflects wavelengths corresponding toother colours: appears orange

opaqueobject absorbs blue

Figure 53 How colours arise from absorption oflight.

Inte

nsity

of a

bsor

ptio

n

ultra violet visible infra red

260 300 340 380 420 460 500 540 580 620 660 700Wavelength/nm

ultra violet visibleviolet blue green yellow red

infra red

Figure 57 The absorption spectrum of carotene(in solution in hexane).

λ/nm

blue light istransmitted

blue light isreflected(Reflectancespectrumshown below)

opaque, colouredobject, eg painting

Inte

nsity

of a

bsor

ptio

n

absorption spectrum

Ref

lect

ance

reflectance spectrum

red and yellow lightis absorbed. (Absorptionspectrum shown below)

transparentcolouredobject, eg solution

600 700500400 600 700500400

paint layer absorbsred and yellowlight

100

0

λ/nm

Figure 59 Absorption and reflectance spectra ofMonastral Blue.

excitationenergy excited electronic state

energy absorbedcorresponds toultraviolet light

excitation energies inthis region correspondto visible radiation

energy absorbedcorresponds tovisible light

excited electronic state

ground electronic states

COLOUREDCOMPOUND

COLOURLESSCOMPOUND

Figure 63 The energy needed to excite anelectron in a coloured compound and in acolourless compound.

–

–

–

–

–

‘hard’ water

‘soft’ water

Ca2+

–Ca2+

Na+

Na+

Na+

Na+

Na+

Ca2+

Figure 10 Ion-exchange columns are used tosoften water. The ion-exchange resin removescalcium ions from the ‘hard’ water, and replacesthem with sodium ions to form ‘soft’ water.

separatedcomponentsof mixture

sample spotcontainingmixture of Aand B

B

A

thin-layer platecoated with silicagel (stationaryphase)

solvent (mobile phase)

lid solvent front

Figure 11 Thin-layer chromatography.

separatedcomponentsof mixture

and B

B

A

phase)

solvent

Figure 11 Thin-layer chromatography.

recorderdetector

outlet tube

syringecontainingsample

inert carrier gas

thermostaticallycontrolled oven

column

Figure 15 A gas–liquid chromatograph.

Figure 15 A gas–liquid chromatograph.

Figure 5 The pH scale.

H+ (aq) +stays roughlyconstantbecause

plenty of HA to make more H+ (aq) if some used up by alkali that gets added

plenty of A– to combinewith any H+(aq) that getsadded

A–HA

Figure 6 How a buffer solution keeps the pHconstant.

pH [H+(aq)]/mol dm–3

Moreacidic

Neutral

Morealkaline

0

1

2

3

4

5

6

7

8

9

10

11

12

13

1

10–1

10–2

10–3

10–4

10–5

10–6

10–7

10–8

10–9

10–10

10–11

10–12

10–13

14 10–14

–

Figure 2 The reaction of chlorine with potassiumiodide solution.

+

––

Cu2+ ion+

–

–

–

+

–+

+

+

+

SO42– ion

–

Zn atomCu atom

– –

–

––

–

+

+

+ +

+

SO42– ion –

+

Zn2+ ion+

Figure 4 The reaction of zinc withcopper(II) sulphate solution: Zn(s) + Cu2+(aq) g Cu(s) + Zn2+(aq)

Figure 5 The general arrangement for anelectrochemical cell.

Velectron flow

ELECTRONSRELEASED

ELECTRONSACCEPTED

oxidationreaction

reductionreaction

Figure 6 An ordinary dry cell – the kind you usein a torch.

– + I– ion

I2 molecules

Cl– ion

K+ ionK+ ion

Cl2 molecules

–

––

––

–

– –

– –

– –

–

++

+

+ ++

++ +

++

+

+

seal+

electronflow alongexternalwire

mixture of chemicalscontaining ammoniumchloride which acceptselectrons and isreduced

card covering

zinc container(–) terminalzinc supplieselectrons and isoxidised

carbon rod(+) terminal

–

high-resistance voltmeter

copperstrip

salt bridge

zinc strip

solution ofZn2+ (aq)(1 mol dm–3)

solution ofCu2+ (aq)(1 mol dm–3)

V

Figure 9 A copper–zinc cell.

Figure 9 A copper–zinc cell.

Figure 11 The standard hydrogen half-cell(sometimes called a standard hydrogenelectrode).

glass tubewith holesin to allowbubbles ofH2(g) to escape

acid solutioncontaining 1.0 mol dm–3

H+ (aq)

H2(g) at 298K and 1atm

platinum electrode

Figure 11 The standard hydrogen half-cell(sometimes called a standard hydrogenelectrode).

platinum electrode

solution containingequal concentrationsof Fe2+(aq) and Fe3+ (aq)

Figure 12 A standard half-cell for theFe3+(aq)/Fe2+(aq) half-reaction.

Figure 2 Enthalpy profile for an exothermicreaction.

Num

ber o

f mol

ecul

es w

ithki

netic

ene

rgy

E

Kinetic energy (E)

300 K

310 K

Figure 4 Distribution curves for molecularkinetic energies in a gas at 300 K and 310 K.

Figure 5 Distribution curve showing collisionswith energy 50 kJ mol–1 and above.

Figure 6 Distribution curves showing the effecton the proportion of collisions with energy50 kJ mol–1 and above of changing thetemperature from 300 K to 310 K.

X

Activation enthalpy

Reactants ∆H

Products

Progress of reaction

En

tha

lpy

Activation enthalpyEa= 50 kJ mol–1

Kinetic energy (E)

Num

ber

of

colli

sio

ns w

ith

kin

etic e

nerg

y E

300 K

310 K

Number of collisions with energy greater than 50 kJ mol–1 at 310 K

Number of collisions withenergy greater than 50kJ mol–1 at 300 K

Kinetic energy (E)

Activation enthalpyEa= 50 kJ mol–1

Num

ber

of

colli

sio

ns w

ith

kin

etic e

nerg

y E

invertedburette

water

yeast suspension+ hydrogen peroxidesolution

Figure 8 Apparatus for investigating the rate ofdecomposition of hydrogen peroxide. The yeastprovides the enzyme catalase.

Figure 10 The decomposition of hydrogenperoxide solutions of differing concentrations.

Figure 11 The initial rate of decomposition ofhydrogen peroxide plotted against concentrationof hydrogen peroxide.

[H2O2] =0.40 mol dm–3

[H2O2] =0.40 mol dm–3

[H2O2] =0.40 mol dm–3

[H2O2] =0.40 mol dm–3

[H2O2] =0.40 mol dm–3

Vo

lum

e O

2/

cm

3

Time /s

26

2422

2018

16

14

1210

86

42

0 20 40 60 80 100 120 140 160 180

Rate

of re

action/c

m3(O

2)s

–1

0.5

0.4

0.3

0.2

0.1

0 0.1 0.2 0.3 0.4

Concentration of hydrogenperoxide/mol dm–3

240

220

200

180

160

140

120

100

80

60

40

20

20 Time/s

100 0 40 60 80 120 140 160 180

Am

ount

of H

2O2

rem

aini

ng/1

0–5 m

ol

to go from200 × 10–5 mol to100 × 10–5 moltakes 27 s

to go from 50 × 10–5 mol to25 × 10–5 mol takes 26 s

to go from100 × 10–5 mol to50 × 10–5 moltakes 27 s

27 s 26 s27 s

Figure 13 Finding half-lives, t½ , for thedecomposition of hydrogen peroxide.

20 Time/s

100 0 40 60 80 120 140 160 180

0.40

0.35

0.30

0.25

0.20

0.15

0.10

0.05

Con

cent

ratio

n of

H

2O2/

mol

dm

–3

concentration = 0.3 mol dm–3

rate = gradient = 0.0068 mol dm–3 s–1

concentration = 0.1 mol dm–3

rate = gradient = 0.0023 mol dm–3 s–1

Figure 14 Using a progress curve to find the rateof a reaction at different concentrations, bydrawing tangents.

Ent

halp

y

Progress of reaction

reactants

product

activation enthalpyfor Step 1

intermediates

Step 1 Step 2

activation enthalpyfor Step 2

Figure 17 For a reaction involving two steps,there are two activation enthalpies.

Second bond forms, and product diffuses away from catalyst surface, leaving it free to adsorb fresh reactants.

4

H HHC

HC

H

H

H

H

New bond forms.

HC

HC

H

3

HH HH

H

CH

CH

H

HHH HH

Bonds break.2

Reactants get adsorbed onto catalyst surface.Bonds are weakened.

1

HH CH

CH

H

HHH

catalyst surface

HH

C

HC

HH

HC HC

H

H

H

HH

Figure 18 An example of heterogeneouscatalysis. The diagrams show a possiblemechanism for nickel catalysing the reactionbetween ethene and hydrogen to form ethane.

activation enthalpyuncatalysed reaction

activation enthalpycatalysed reaction

uncatalysedreaction

catalysedreaction

reactants

products

∆H

Ent

halp

y

Progress of reaction

Figure 19 The effect of a catalyst on the enthalpyprofile for a reaction.

Ent

halp

y

Progress of reaction

Figure 19 The effect of a catalyst on the enthalpyprofile for a reaction.

Den

sity

/ g

cm–3 2

1

3

0Li Be B C N O F Ne Na Mg Al Si P S Cl Ar

Figure 3 Densities of elements in Periods 2 and 3.

Figure 4 Melting and boiling points of elementsin Period 3.

Mel

ting

and

boili

ngpo

ints

/ K

Na Mg Al Si P S Cl Ar

m.p.

Key

b.p.

1000

0

2000

3000

Figure 5 Variation in atomic size across Period 3.

Ato

mic

radi

us /

nm

Na Mg Al Si P S Cl Ar

0.2

0.1

0

Firs

t ion

isat

ion

enth

alpy

/ kJ

moI

–1

1000

0H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca

2000

Figure 6 First ionisation enthalpies of elements1–20.

Element Atomic number Electronic arrangement3d

Sc

Ti

V

Cr

Mn

Fe

Co

Ni

Cu

Zn

21

22

23

24

25

26

27

28

29

30

[Ar]

[Ar]

[Ar]

[Ar]

[Ar]

[Ar]

[Ar]

[Ar]

[Ar]

[Ar]

building up of inner 3d sub-shell

outer shell

4s

Figure 20 Arrangement of electrons in theground state of elements of the first row of the dblock. [Ar] represents the electronicconfiguration of argon.

force

(a) (b)

force The open circles representatoms of iron. The blackcircles are the larger atomsof a metal added to make analloy.

Figure 22 The arrangement of metalatoms in a crystal (a) before and (b) afterslip has taken place. The shaded circlesrepresent the end row of atoms.

Figure 23 The arrangement of metal atoms in an alloy.

Sc Ti V Cr Mn Fe Co Ni Cu Zn+1

+5

+7

+4 +4 +4

+2 only+2+2 +2 +2 +2 +2 +2

+6 +6 +6

+3 only +3 +3 +3 +3 +3 +3 +3 +3

Figure 24 Oxidation states shown by elements inthe first row of the d block. The most importantoxidation states are in boxes.

Figure 27 An octahedral complex of Fe(III). Coordination number 6.

Figure 28 A tetrahedral complex of Ni(II). Coordination number 4.

Figure 29 A square planar complex of Ni(II). Coordination number 4.

Figure 30 A linear complex of Ag(I).Coordination number 2.

Figure 32(a) Edta4–, a hexadentate ligand.(b) The nickel–edta complex ion [Ni(edta)]2 –.

octahedral complex of FE(III)

coordination number 6

CN

CN

CN

CN

NC

NC

Fe

3–

shape

CN

NC

Fe

NC

NC

NC

Fe

CN

CN

CN

CN

CN

CN

CN

ClCl

ClCl

Cl Cl

ClCl

Cl Cl Cl

Cl

NiNiNi

tetrahedral complex of Ni(II)

coordination number 5shape

2–

Ni Ni Ni

NC

NC

NC

NC NC

NC

CN

CN

CN

CN

CN

CN

2–

square planar complex of Ni(II)

coordination number 4shape

H3N Ag NH3

+

O

CO

O O

O

OO

O

O

O

O

O

O

O

O

C

C

CH2

C

C

C

C

C

CH2 CH2

CH2

CH2

CH2

CH2 CH2

CH2

CH2

H2C

H2C

2–

Ni

(a)

(b)

Figure 33 Relative energy levels for the five 3dorbitals of the hydrated Ti3+ ion.

Figure 36 The cis and trans isomers of[Co(NH3)4Cl2]+ have different colours.

energy

Average energy

of 3d orbitals in

[Ti(H2O)6]3+

if there was no

splitting [Ti(H2O)6]3+

ground state

3d level split

[Ti(H2O)6]3+

excited state

light

hv ∆E

cis isomer: violet trans isomer: green

NH3

NH3

NH3

H3N

NH3 NH3

NH3

NH3

Cl

Cl

Cl

Cl

Co Co

++

Name Molecular Full structural Shortened Furtherformula formula structural shortened

formula to

methane

ethane

propane

Table 2 Structural formulae of alkanes.

CH4CH4 H C H

H

H

C2H6 H C C

H

H

H

H

H

CH3CH3CH3 CH3

C3H8 H C C C

H

H H H

H H

H CH3CH2CH3CH3 CH2 CH3

109°

represents a bond in the plane of the paper

represents a bond in a direction behindthe plane of the paper

represents a bond ina direction in front ofthe plane of the paper

H

C

H HH

Figure 5 The three-dimensional shape ofmethane.

a simpler way of drawingethane which shows theshape less accurately

C C

H

H

H

H

H

H

Figure 6 The three-dimensional shape of ethane.

C C

H

HH

HH

H

Figure 7 The three-dimensional shape of butane.

CC

CC

H

HH

HH

H

H

H

H

H

skeletal formulaof butane

ALK

AN

ESIs

omer

isat

ion

Ref

orm

ing

Cra

ckin

gSt

eam

cra

ckin

g C

atal

ytic

cra

ckin

gFe

edst

ock

C4

– C

6al

kane

sna

phth

ana

phth

a/ke

rose

nega

s oi

l

Pro

duct

sam

e m

olec

ular

form

ula

assa

me

num

ber o

f C a

tom

s as

reac

tant

s;m

ore

mol

ecul

es;

mor

e m

olec

ules

;m

olec

ules

reac

tant

s;cy

clic

few

er C

ato

ms

than

reac

tant

s;

few

er C

ato

ms

than

reac

tant

s;

bran

ched

smal

l mol

ecul

es, s

uch

asso

me

unsa

tura

ted;

C

2H4,

C2H

6, C

3H6,

C3H

8,so

me

bran

ched

; C

4an

d C

5al

kene

s an

d so

me

cycl

ical

kane

s

Con

ditio

nsP

t/Al 2

O3;

P

t/Al 2

O3;

no

cat

alys

t; ze

olite

; 15

0 °C

500

°C;

900

°C;

500

°Chy

drog

en is

recy

cled

thro

ugh

mix

ture

to

shor

t res

iden

ce ti

me;

redu

ce ‘c

okin

g’st

eam

is a

dilu

tent

to p

reve

nt‘c

okin

g’

Exa

mpl

e

Use

s of

to im

prov

e oc

tane

ratin

g of

pet

rol

to im

prov

e oc

tane

ratin

g of

pet

rol

to m

anuf

actu

re p

olym

ers

to im

prov

e oc

tane

ratin

g of

pet

rol

prod

ucts

Furth

er

Dev

elop

ing

Fuel

ls s

tory

line,

Dev

elop

ing

Fuel

s st

oryl

ine,

Th

e Po

lym

er R

evol

utio

n D

evel

opin

g Fu

ells

sto

rylin

e,de

tails

S

ectio

n D

F4

Sec

tion

DF4

st

oryl

ine,

Sec

tions

PR

3 S

ectio

n D

F4C

hem

ical

Idea

s 15

.2 an

d PR

4 C

hem

ical

Idea

s 15

.2C

hem

ical

Idea

s 15

.2

Tabl

e 5

The

actio

n of

hea

t on

alka

nes.

Skel

etal

form

ulae

are

use

d in

the

exam

ples

.

is th

e sk

elet

al fo

rmul

a fo

r a b

enze

ne ri

ng.

++

+

H2

+

3H

2

C–C bond length0.139 nm

120°

C

CC

C

CCH

H

H

H

H

H

Figure 11 The structure of the benzene ring.

Scale 0.1nm0

Figure 14 An electron density map for benzeneat –3 °C. The lines are like contour lines on amap: they show parts of the molecule with equalelectron density.

Figure 15 Enthalpy changes for thehydrogenation of benzene and the hypotheticalKekulé structure.

regions of higher electrondensity above and belowthe benzene ring

Figure 16 The regions of higher electron densityabove and below the benzene ring.

Enth

alp

y

Progress of reaction

∆H = –360 kJ mol–1

(estimated enthalpy change

for Kekulé’s benzane)

C6H12 cyclohexane

+ 3H2

+ 3H2

∆H = –208 kJ mol–1

measured enthalpy

change for benzane)

Full structural Skeletal Nameformula formula

1-chloropropane

1,2-dichloropropane

3-bromo-1-chlorobutane

Table 1 Naming halogenoalkanes.

Cl

H

C

H

H C C

H

H

Cl

H

H

Cl

ClH

C

H

H C C

Cl

H

Cl

H

H

Cl

BrH

C

H

H C C

Br

H

C

H

H

Cl

H

H

Table 3 Some common nucleophiles.

Full structural Skeletal Nameformula formula

propan-1-ol

propan-2-ol

pentan-3-ol

Table 4 Naming alcohols.

H

C

H

H C C OH

H

H

H

H

OH

H

C

H

H C C H

OH

H

H

H

OH

H

C

H

H C C C

H

H

OH

H

C H

H

H H

H

OH

Name and Structure, showingformula lone pairs

hydroxide ion, OH–

cyanide ion, CN–

ethanoate ion, CH3COO–

ethoxide ion, C2H5O–

water molecule, H2O

ammoniamolecule, NH3

H

H H

H HH

O

O

O

O

O

N

CH3

CH3CH2

N C

C

Table 6 Some examples of acid derivatives.

Acid derivative Dealt with in Section(s) Example

13.5 and 14.2

13.5 and 14.2

13.8

13.5 and 14.2

ester

acyl chloride

amide

acid anhydride

C

O

OR

C

O

Cl

C

O

NH2

C

O

O

C

O

ethyl ethanoate

ethanoyl chloride

ethanamide

ethanoic anhydride

CH3 C

O

O

CH3 C

O

Cl

CH3 C

O

NH2

CH3 C

O

O

CCH3

O

CH2CH3

Type of alcohol Position of —OH Examplegroup

primary at end of chain: propan-1-ol

secondary in middle of chain: propan-2-ol

tertiary attached to a carbonatom which carriesno H atoms: 2-methylpropan-2-ol

CH3CH2 C OH

H

H

CH3 C CH3

H

OH

CH3 C CH3

CH3

OH

Table 7 Primary, secondary and tertiary alcohols.

H

C

H

R OH

H

C

OH

R R'

R'

C

OH

R R''

Figure 6 How to name an ester.

ethyl ethanoate

This part comes fromthe alcohol and is

named after it

This part comesfrom the acid andis named after it

O

OCH3

CH3

CH2

C

H

CH O C

C

O

H

C

O

H

H

O

C

C

O

O

R1 (long carbon chain)

R2

R3

glycerol part −always the same

fatty acid parts − R1, R2 and R3

may be different or the same

Figure 7 The general structure of the triestersfound in fats and oils.

O

O

O

O

O

Unsaturated triglyceride

O

O

O

O

O

O

O

Saturated triglyceride

Figure 9 Representations of triglycerides.

carboxylic acid amine amide group

CO

N C

O

H

+ H2ONO

H

H

H

Figure 18 Making a secondary amide.

acid groupamino group

α-carbon: the first carbon atomattached to the –COOH group

H

R

H2N C COOH

Figure 20 The generalised structure of an α-amino acid.

Figure 21 How an amino acid forms a zwitterion.

C

R

H

C

O

OH

N

H

H

C

R

H

C

O

O−

N

H

H

H

receives H+ froma COOH group

H+ donated toan NH2 group

a zwitterion

+

+

azo compound

N + H+N

diazonium ion

NN+

coupling agent

H

Figure 22 A generalised coupling reaction.

+ HCl(g)sunlight

Cl2(g)

room temp alkene

n

addition polymer

trace O2(g)

200 oC and1500 atm.

H2O(g)phosphoric

acid catalyst 300 oC and

60 atm.

HBr

conc H2SO4followedby H2O

or

organic solvent

Br2

organic solvent

H2(g)

finely divided Niat 150 oC and 5 atm.(or Pt at room tempand 1 atm.)

HC CH

CH2 CH2

HC CH

H Br

HC CHHC CH

H OH

HC CH

Br Br

CH2 CH

Cl

Figure 2 Reactions of alkenes.

Figure 3 Reactions of halogenoalkanes.

alcohol

heat in asealed tube

halogenoalkane

c. NH3(aq)

H2O(l)

NaOH(aq)amine

alcohol

slow

reflux

R OH

R HalR NH2

R OH

R CH2 O C R'

O

R CH2 OH

R CHO R COOH

R CH2 Br

R CH2 Cl

R CH CH2

ester

bromoalkane

chloroalkane

carboxylic acidaldehyde

alkeneprimary alcohol

R'−COClor (R'CO)2O

anhydrousconditions

R'−COOHc. H2SO4 catalystreflux

c. HCl

HBr(aq)(NaBr(s) + c. H2SO4)

reflux

Cr2O72−/H+(aq)

reflux

Cr2O72−/H+(aq)

refluxNaBH4

Al2O3(s), 300 °C

or c. H2SO4

reflux

Figure 4 Reactions of primary alcohols.

room temp

R

O

C

H

carboxylate ion

carboxylic acid

NaOH(aq) HCl(aq)

R'

O–

O

R

O

C

OHc. H2SO4 catalyst

reflux with

aqueous acid or alkali*

R

O

C

O

R C

O

acid anhydride

R' OH

anhydrous

conditions

reflux

R

O

C

O R'

ester

R' OHroom

temperature

acyl chloride

R

O

C

Cl

R' NH2

room

temperature

room

temperature

primary amide

R

O

C

NH2

c. NH3(aq)

R

O

C

NH R'

secondary amide

R C

O

H

aldehyde

C

OH

H

CN

RC

OH

H

H

R

primary alcohol a cyanohydrin

R C

O

OH

carboxylic acid

HCN

(+ alkali)

NaBH4

Cr2O72−/H+(aq)

refluxor heat withFehling'ssolution

R C

O

R'

ketone

C

OH

R'

CN

RC

OH

R'

H

R

secondary alcohol a cyanohydrin

HCN

(+ alkali)

NaBH4

Figure 6 Reactions of ketones.

Figure 5 Reactions of aldehydes.

Figure 7 The reactions of carboxylic acids and some related compounds.

Note Esters and amides are both hydrolysed by heating with aqueous acid or aqueousalkali. Alkaline hydrolysis gives the salt of the corresponding carboxylic acid. The freecarboxylic acid is formed on acidification of the solution.

Figure 8 Reactions of arenes.

Cl

Cl2(g)AlCl3 room

temperature

NO2 c. HNO3c. H2SO4< 55 °C

alkylation

R

R Cl AICI3

reflux

Friedel-Craftsreactions

R COCl or(RCO)2O

acylation

O

CR

finely divided NiH2(g)

300 °C, 30 atm.

Br2(l) FeBr3 (or FE)room

temperature

Br

SO2OH

c. H2SO4reflux

AICI3reflux

Feedstock(reactants)

Feedstockpreparation

Energy in or out

REACTION

Temperature, pressure, catalystSeparation

Products

Co-products

Recycle loop Unused feedstockInput or removal of energy may be required at any stage

(and by-products)

Figure 1 Sequence of unit operations in achemical plant.

Starting mixture

Batch reactorAt start Reactants in Some time later

Product mixture

Continuous (stirred tank) reactor

Stirrer

Product mixture continuously removed

Reactants added continuously(a) (b)

Figure 2 Comparison of (a) batch and (b) continuous tank reactors.

LiverpoolManchester

Castner/KellnerWorks

Lancaster

Durham

Newcastle

SunderlandCarlisle

Annan

Dumfries

Selkirk

Jedburgh

PeeblesLanark

Stirling

Kelso

Hawick

GlasgowEdinburgh

STRATHCLYDE

DUMFRIES &GALLOWAY

Kendal

Chester

Hillhouse Works

CLWYD CHESHIRE

LANCASHIRE

CUMBRIA

NORTH WESTERNETHENE PIPELINE

SOLWAY FIRTH

WILTONGRANGEMOUTH

TRANS PENNINEETHENE PIPELINE

NORTHYORKSHIRE

NORTHUMBERLAND

FIRTH OF FORTH

ETHENEPIPELINE

Wilton Works

MOSSMORRANGRANGEMOUTH

Figure 3 Pipelines from BP, Grangemouth, andExxon, Mossmorran, for the distribution ofethene.

OIL

Fractionaldistillation

LPG Naphtha

Steamcracking

Ethene,propene

Steamcracking

Ethene,propene

Reforming

Branched alkanes, cycloalkanesand aromatic hydrocarbons

for high-grade petrol

Catalyticcracking

Gas Oil

Ethene, propene,high-grade petrol

ResidueKerosene

Figure 5 Feedstocks from oil.

Figure 4 Feedstocks from natural gas.

NATURAL GAS

Fractionaldistillation

Steamcracking

Methane Ethane

Ethene,propene

Steamcracking

Propane

Ethene,propene

Steamcracking

Butane

Ethene,propene

Figure 6 (a) An example of how energy can be used in a chemical process. (b) A diagram to illustrate a heat exchanger.

(a)

Reactants

at 20°C

(a)

Heat exchanger

Reactants

at 20°C

Reactants

at 180°C

Reactor

at 200°C

Products at 200°C

Products at about 60°C

(b) Steam

in

Steam

out

Hot

feed out

Cold

feed in

Cross section:Condensed

steamSteam pipe

A single-pass tubular heat exchanger