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TABLE OF CONTENTS
3

CHAPTER 1

3

CHAPTER 2

5

CHAPTER 3

7

CHAPTER 4

9

CHAPTER 5

10

CHAPTER 6

11

CHAPTER 7

12

CHAPTER 8

13

CHAPTER 9

15

CHAPTER 10

Atoms, Molecules & Stoichiometry
Atomic Structure
Chemical Bonding
States of Matter
Chemical Energetics
Electrochemistry
Equilibria
Reaction Kinetics
Chemical Periodicity
Group II – Alkaline Earth Metals

CIE AS LEVEL- CHEMISTRY [9701]

16

CHAPTER 11

16

CHAPTER 12

17

CHAPTER 13

20

CHAPTER 14

22

CHAPTER 15

23

CHAPTER 16

25

CHAPTER 17

26

CHAPTER 18

26

CHAPTER 19

Group 17 – Halogens
Nitrogen & Sulphur
Introduction to Organic Chemistry
Hydrocarbons
Halogen Derivatives
Hydroxy Compounds
Carbonyl Compounds
Carboxylic Acids & Derivatives
Analytical Techniques

© Copyright 2016, 2015 by Z Notes
First edition © 2015, by Emir Demirhan, Saif Asmi & Zubair Junjunia for the 2015 syllabus
Second edition © 2016 updated by Saif Asmi & Zubair Junjunia for the 2016 syllabus
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No part of this document may be copied or re-uploaded to another website without the express, written permission of the copyright owner
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This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4
...


CIE AS LEVEL- CHEMISTRY [9701]
1
...
ATOMIC STRUCTURE

1
...
1 Subatomic Particle

Relative

Atomic
mass (Ar):

weighted average mass
of an atom

Molecular
mass (Mr):
Formula
mass:
Isotopic
mass:

mass of a molecule
mass of one formula
unit of a compound
mass of a particular
isotope of an element

compared
with 12C
where one
atom of 12C
has mass of
exactly 12
units

Subatomic
Particle
Protons (P)
Neutrons (n)
Electrons (e-)

Relative
Charge
+1
0
-1

Relative mass/
a
...
u
1
1
1/1840

2
...
2 The Mole
 Mole: amount of substance that has the same number
of particles (atoms, ions, molecules or electrons) as
there are atoms in exactly 12g of the carbon-12 isotope
...
02 × 1023

1
...
4 Empirical and Molecular Formulae

2
...
or proton no
...
of protons
 Atomic mass or nucleon no
...
of P + N

𝑀𝑜𝑙𝑒𝑐𝑢𝑙𝑎𝑟 𝐹𝑜𝑟𝑚𝑢𝑙𝑎 = (𝐸𝑚𝑝𝑖𝑟𝑖𝑐𝑎𝑙 𝐹𝑜𝑟𝑚𝑢𝑙𝑎) 𝑛
Where 𝑛 =
% 𝐶𝑜𝑚𝑝𝑜𝑠𝑖𝑡𝑖𝑜𝑛 =

𝑀𝑜𝑙𝑒𝑐𝑢𝑙𝑎𝑟 𝑀𝑎𝑠𝑠
𝑀𝑎𝑠𝑠 𝑜𝑓 𝐸𝑚𝑝𝑖𝑟𝑖𝑐𝑎𝑙 𝐹𝑜𝑟𝑚𝑢𝑙𝑎

𝐴𝑡𝑜𝑚𝑖𝑐 𝑀𝑎𝑠𝑠 × 𝑁𝑜
...
of e-s
 Isotopes: are atoms of the same element with the same
proton number but different number of neutrons

1
...
4 Electronic Configuration

𝑀𝑎𝑠𝑠
𝑀𝑜𝑙𝑎𝑟 𝑀𝑎𝑠𝑠
𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑎 𝐺𝑎𝑠 = 𝑀𝑜𝑙𝑒𝑠 × 24
 Formula applies to gases at r
...
p
...
(P
...
Q
...
6 Shapes of Subshells
𝑠-Subshell

 Spherical shape
 Increases in size as P
...
increases

𝑝-Subshell

Nuclear
Charge
Shielding
Effect
Atomic
Radius

2
...
8 Factors affecting Ionization Energy

Stable
Config
...
In opposite
direction they create a spin to reduce repulsion
 Completely filled or half filled (i
...
one e- in each orbital)
are more stable (reduced repulsion)
-

 +ve charge due to protons in nucleus
 Greater nuclear charge  greater ionization
energy
 Inner shells of e-s repel outermost e-s, thus
shielding them from +ve nucleus
...
E because lesser
attractive force between nucleus & outer e-s
 Distance from the center of the nucleus to
the outermost orbit
 Greater radius  lower I
...
E needed to remove e-s from
completely or half-filled orbitals

2
...
E Trends
First Ionization Energy Trends
Down a Group
Across a Period
DECREASES
INCREASES
 New shells added
 Shell no
...
increases
valence e s decreases
 Effective nuclear charge
 Shielding effect
increases
increases
 Atomic radius decreases

2
...
E Across 3rd Period

 Dumbbell shape

2
...
E)
 1st I
...
E is
higher than previous one
because as e-s are
removed, protons > e-s ∴
attraction between
protons and remaining
Big jump occurs
electrons increases
between I
...
Es have
∴ part of 1st gp
large jump in their value
when e-s removed from
lower energy shell
 Deduce group no
...
E of Al lower than Mg: e- removed in Al is from higher
energy 3p orbital which is further away from nucleus
than 3s e- being removed from Mg
...
E of Al is lower than Mg
 I
...
11 Ionic Radius

3
...
decreases, screening
effect decreases but the
attraction of nucleus increases
...
of shells
𝒏− 𝟏
𝒏

 Coordinate bond is a covalent bond where both
electrons in the bond come from the same atom
 Conditions:
o An atom should have a lone pair of electrons
o An atom should be in need of a pair of electrons
 Donor: the atom that supplies the pair of electrons
 Acceptor: the atom that accepts the pair of electrons
 Coordinate bond is represented by an “” drawn from
the atom donating to towards the atom accepting
 Formation of Ammonium ion (𝑵𝑯+ ):
𝟒

 Proton no
...
CHEMICAL BONDING
3
...

 Structure: giant ionic lattice,
crystalline solids
 Have high melting and boiling points

o Above 750oC, exists as vapor & covalent molecule AlCl3
o As vapor cools, exists as dimer Al2Cl6
o Bond angle as AlCl3 = 120o
o Bond angle as Al2Cl6 = 109
...
4 Orbital Overlap

S–S
 Covalent bond is the bond formed by the sharing of
pairs of electrons between two atoms
...
2 Covalent Bonding

Sigma
σ

P–P

 Coordination number: number of oppositely charged
ions that surround a particular ion in an ionic solid

Sigma
σ

Sigma
σ

P–P

 For a covalent bond to form, atomic orbitals containing
unpaired valence electrons must overlap each other

Pi
𝝅

 Sigma bond has greater overlap ∴ 𝜎 > 𝜋
 Pi bond cannot exist without a Sigma bond
...
5 Shapes of Covalent Molecules

3
...
8 Bonds

120O
BF3
-

4 Pairs of e s
4 bonded

109
...
5O
H2O

5 Pairs of e-s
5 bonded

Trigonal
Bipyramid

PF5

90O

Octahedral

SF6

3
...


...


Longer bond

Weaker bond

More reactive

3
...
STATES OF MATTER

3
...
of
electron

↓ nuclear
attraction

Faster edistortion

Stronger
force

Permanent Dipole-Dipole Forces
 Weak forces present between polar molecules
 Molecules always attracted to charged rod, whether +ve
or –ve because molecules have +ve and –ve charges

3
...
12 Summary

4
...

 Noble gases such as helium and neon approach ideal
behavior because of their low intermolecular forces
...
and high pressure
 Molecules are close to each other
 Volume of molecules not negligible relative to container
 VDW forces present, pulling molecules to each other
 Pressure is lower than expected from ideal gas
 Effective volume is less than expected from ideal gas

4
...
3 Liquid State
 Particles touching but may have gaps
 Have 𝐸 𝐾 to slide past each other in random motion
 Enthalpy of fusion: heat energy required to change 1
mole of solid into a liquid at its melting point
Page 7 of 27

CIE AS LEVEL- CHEMISTRY [9701]
 Heating a solid (melting):
o Energy transferred makes solid particles vibrate faster
o Forces of attraction weaken & solid changes to liquid
 Enthalpy of vaporization: heat energy required to
change 1 mole of liquid into a gas at its boiling point
 Heating a liquid (vaporization):
o Energy transferred makes liquid particles move faster
o Forces of attraction weaken
o Highest energy particles escape first
o Liquid starts to evaporate – temp
...
p
...
at b
...

 The evaporation of a liquid in a closed container
o Constant evaporation from surface
o Particles continue to break away
from surface but are trapped in
space above the liquid
o As gaseous particles collide,
some of them hit the surface
of the liquid again, and become trapped there
o An equilibrium is set up in which number of particles
leaving surface is balanced by number rejoining it
...

 Vapor pressure: pressure exerted by a vapor in
equilibrium with a liquid
...
↑

Ek ↑

Forces weaken

More vapor

4
...
p
...
p
...
p
...
p
...
p
...
p
...
p
...
p
...
2 Enthalpy Change Definitions
Standard molar enthalpy change of
Combustion

Formation

Solution

Hydration

Atomisation

Neutralization

∆𝑯 𝑪

∆𝑯 𝒇

∆𝑯 𝒔𝒐𝒍

∆𝑯 𝒉𝒚𝒅

∆𝑯 𝒂𝒕

∆𝑯 𝒏

1 mole of 𝐻 + and
𝑂𝐻 − combine to form 1
mole of 𝐻2 𝑂

C atoms in pentagonal and
C atoms in hexagonal
hexagonal rings
rings only
Spherical
Cylindrical
C60 molecules held
Structure is rod like due
together by VDWs
to continuing rings
Conducts heat and electricity
Very strong and tough
Insoluble in water
High m
...
/b
...


 Metal + Acid or Water
 Thermal decomposition
 Neutralization
 Dissolving salts
 Combustion
 Photosynthesis
 Condensation & Freezing  Boiling & Evaporation
 Standard Enthalpy Conditions:
o Temperature: 298𝐾 or 25 𝑜 𝐶
o Pressure: 101𝐾𝑃𝑎 or 1𝑎𝑡𝑚
o Solution Conc
...
5 Ceramics

 Finite resource: resource which doesn't get replaced at
the same rate that it is used up
...
6 Recycling

1 mole of element or
compound is completely
combusted

Enthalpy change when

 Ceramic: an inorganic non-metallic solid prepared by
heating one or a mixture of substance(s) to a high temp
...
p
...
p
...
3 Bond Energy
 Energy needed to break a specific covalent bond
 Also how much energy is released when a bond forms

5
...
: add –ve or +ve to show rise/fall

5
...
1 Energy Change in Reactions
Exothermic Reactions
 Energy given out
 Surrounding warmer
 Bond making
 ∆𝐻 negative
𝐸 𝑅𝑒𝑎𝑐𝑡𝑎𝑛𝑡𝑠 > 𝐸 𝑃𝑟𝑜𝑑𝑢𝑐𝑡𝑠

Endothermic Reactions

Endothermic Reactions
 Energy taken in
 Surrounding cooler
 Bond breaking
 ∆𝐻 positive
𝐸 𝑅𝑒𝑎𝑐𝑡𝑎𝑛𝑡𝑠 < 𝐸 𝑃𝑟𝑜𝑑𝑢𝑐𝑡𝑠

5
...


Page 9 of 27

CIE AS LEVEL- CHEMISTRY [9701]
 Reason to use Hess’s Law:
o Std
...
g
...
6 Calculating Enthalpy Change of…
…Reaction from Formation

Covalent molecules:
 Rules:
o Atoms in a diatomic molecule; oxidation number = 0
o Oxygen in a compound; oxidation number = -2
o Oxygen as peroxide; oxidation number = -1
o 1st group elements & hydrogen; oxidation number = +1
o H with highly reactive metal; oxidation number = -1
 Following these rules, all other atoms in a covalent bond
must balance out the charge

6
...
g
...
3 Balancing Equations
…Hydration from Anhydrous Salt

 Equation:
𝐻𝐼 + 𝐻𝑁𝑂3 → 𝐼2 + 𝑁2 𝑂3 + 𝐻2 𝑂
 Half ionic:
2𝐼 − − 2𝑒 − → 𝐼2
𝑁 +5 + 2𝑒 − → 𝑁 +3
 For every 2 iodines, there will be 1 nitrogen
 Thus first put in correct ratio for iodine and nitrogen
then balance hydrogens and oxygens
 Balanced:
4𝐻𝐼 + 2𝐻𝑁𝑂3 → 2𝐼2 + 𝑁2 𝑂3 + 3𝐻2 𝑂

6
...
ELECTROCHEMISTRY

 Electrolysis: decomposition of an electrolyte by an
electric current
...
g
...
Steel/titanium used in industry
...
5 Products of Electrolysis

6
...
3 Manufacture of Ammonia

Higher in
reactivity
then H+

H2 formed

Lower in
reactivity
then H+

Metal
formed

Aqueous
Electrolyte
Halide
present
At the
anode

Concentrated

Halogen
fomed

Dilute

HABER PROCESS FLOWCHART
Methane and steam
Fractional distillation of
liquid air
𝐶𝐻4 + 𝐻2 𝑂 ⇌ 𝐶𝑂 + 3𝐻2

Oxygen
formed

Halide not
present

Hydrogen

Compressed and Heated
 Catalyst: Iron beds
 Temp: 500oC
𝑁2 + 3𝐻2 ⇌ 2𝑁𝐻3
 Pressure: 200atm

Oxygen
Formed

7
...
4 Manufacture of Sulphuric Acid
CONTACT PROCESS FLOWCHART
Burning fossil fuels
Fractional distillation of
air

7
...
2 Equilibrium Constants
Equilibrium Constant

2𝑆𝑂2 + 3𝑂2 ⇌ 2𝑆𝑂3

Expressed in terms of
Expressed in terms of
concentration
partial pressure
𝑚𝑜𝑙𝑠
[𝑃𝑟𝑜𝑑𝑢𝑐𝑡]
𝑝(𝑃𝑟𝑜𝑑𝑢𝑐𝑡) 𝑚𝑜𝑙𝑠
𝐾𝐶 =
𝐾𝑃 =
[𝑅𝑒𝑎𝑐𝑡𝑎𝑛𝑡] 𝑚𝑜𝑙𝑠
𝑝(𝑅𝑒𝑎𝑐𝑡𝑎𝑛𝑡) 𝑚𝑜𝑙𝑠
Only liquids and gases
Only gases
 Large value of 𝐾 𝐶 /𝐾 𝑃 ⇒ equi
...
towards reactants side
 𝐾 𝐶 /𝐾 𝑃 changes only with changes in temperature
 The amount of reactants that disappear will always
appear in the products in the same ratio as present in a
balanced equation

 Catalyst: V2O5
 Temp: 500oC
 Pressure: 1atm (slight)

𝑆𝑂3 + 𝐻2 𝑆𝑂4 ⟶ 𝐻2 𝑆2 𝑂7 (𝒍) [Oleum]
𝐻2 𝑆2 𝑂7 + 𝐻2 𝑂 ⟶ 2𝐻2 𝑆𝑂4
Sulphuric Acid
 SO3 not dissolved directly into water because reaction
explosive and causes H2SO4 to vaporize
 Forward reaction exothermic ∴ temp
...
5 Acid-Base Equilbria
 Brønsted-Lowry Theory:
o An acid is a proton (H+) donor
o A bases is a proton (H+) acceptor
 Amphoteric: substances that can act like bases or acids

7
...
3 Effect of Temperature

 𝐻𝐶𝑙 is a conjugate acid of base 𝐶𝑙 − & vice versa
+
 𝑁𝐻4 is a conjugate acid of base 𝑁𝐻3 & vice versa

7
...
4 Effect of Catalyst
 Catalyst: a substance that increases rate of reaction but
remains chemically unchanged itself at the end
 Does not alter the chemical composition of substances
and only lowers the activation energy
 It provides a new route or mechanism to follow for
reactants that requires less energy

8
...
1 Effect of Concentration Changes
 Increasing conc
...


8
...
& catalyst on rate of reaction
 Based on distribution of energy among reacting
molecules under different conditions

 Curve unchanged, only activation energy changes
 Homogeneous catalysts: reactant and catalyst are in
the same physical state
 Heterogeneous catalysts: reactant and catalyst are in
different physical states
 Enzymes: a protein molecule that is a biological catalyst
...
CHEMICAL PERIODICITY
Group
Element
Character
Structure
Bonding

1
Sodium

2
Magnesium
Metal
Giant metallic lattice

3
Aluminium

4
Silicon
Metalloid
Macromolecular
Covalent bonds
between atoms

Metallic bond between cations and delocalized e-

5
Phosphorous

6
7
Sulphur
Chlorine
Non-metals
Simple molecular covalent
Intra = covalent
Inter = weak VDWs

0
Argon
Simple atoms
Atoms held by
VDWs

Diagram

9
...
2 Reaction of Oxides with Water
Oxid
...
acidic
S
...
acidic

9
...

Nature
+1
S
...
Alkaline

NO REACTION
P2O3(s) + 3H2O(l) 2H3PO3(aq)
P2O5(s) + 3H2O(l)  2H3PO4(aq)
SO2(g) + H2O(l)  H2SO3(aq)
SO3(g) + H2O(l)  H2SO4(aq)

9
...
Acidic
S
...
)  Na2SiO3
 Sulphur dioxide and trioxide are strongly acidic
With
Produces
SO2(g) NaOH
NaHSO3(aq)
SO2(g) Excess NaOH Na2SO3(aq) + H2O
SO3(g) NaOH
NaHSO4(aq)
SO3(g) Excess NaOH Na2SO4(aq) + H2O

Page 13 of 27

CIE AS LEVEL- CHEMISTRY [9701]
9
...

+1
+2
+3
+4
+3
+5

9
...
Acidic
S
...
6 Reactions of Chloride with Water
Reaction
Nature
NaCl(s)
NaCl(s) + H2O(l)  NaCl(aq)
Neutral
MgCl2(s) MgCl2(s) + H2O(l) MgCl2(aq)
W
...
Acidic
PCl3(l)
PCl3(l) + H2O(l) H3PO3(aq) + HCl(g)
S
...
Water is polar
∴ positive Na+ attracted to OH- while Cl- attracted to H+
 MgCl2 slightly acidic because Mg ion has smaller radius &
higher charge ∴ attraction to water is so strong that H2O
loses a proton and solution becomes slightly acidic

AlCl3

 Ionic radius decreases across a period however, since
non-metals gain electrons, they have one more shell
than metals therefore they always have a larger radius
than metal ions

9
...
7 Atomic Radius

 Na  Al m
...
increases because delocalized e- per atom
increases making metallic bond stronger
 Si has highest m
...
due to giant covalent structure
 The larger the molecule size, the stronger the VDW
forces ∴ S8 > P4 > Cl2 > Ar

9
...

 so atomic radius decreases
...
of delocalized electrons which
can carry charge increases
 Silicon is a semi-conductor
 Non-metals – covalent ∴ no charge

Page 14 of 27

CIE AS LEVEL- CHEMISTRY [9701]
9
...
2 Reaction of Gp
...
2 metals tarnish in air forming oxide coatings
 Burn vigorously in oxygen forming white solids

10
...
of protons increases

 Solubility of M, MO and M(OH)2 increases down group
 Alkalinity of solution increases down the group
 Solubility of M and MO increases down the group
 Solubility of M(OH)2 and MSO4 decreases down group

9
...
4 Reaction with Acid
M(s) +Acid(aq) → Salt + Hydrogen
MO(s) +Acid(aq) → Salt + Water
M(OH)x(s) +Acid(aq) → Salt + Water
MCO3(s) +Acid(aq) → Salt + Water + Carbon Dioxide

10
...
2 Metals
∆H

MCO3(s) → MO(s) +CO2(g)
 Generally increases as no
...


10
...
GROUP II – ALKALINE EARTH METALS
 m
...
/b
...
decreases down group: atoms/ions get larger,
distance between nuclei & e-s increases ∴ bonds weaker
 m
...
/b
...
higher in gp
...
increases

 Calcium compounds:

10
...
E) decreases down the group
 The lower the I
...
2 less reactive than gp
...
E = 1st I
...
and 2nd I
...

 Gp
...
, for extraction of iron,
glass industry, neutralize soil or chemical waste
Page 15 of 27

CIE AS LEVEL- CHEMISTRY [9701]
11
...
5 Halide ions and aq
...
1 Trends in Colour and Volatility
m
...
& b
...

increases

Volatility
decreases


Fluorine
Yellow
Gas
Chlorine Yellow-Green
Bromine Orange-Brown Liquid
Iodine
Grey-Blue
Solid
Astatine
Black
 As atomic number increases, the number of electrons
increases, this increases VDW forces so stronger bonds
thus m
...
/b
...
increases and volatility decreases

Metal Halide + Conc
...
H2SO4(aq) is an oxidising agent
 This reaction is used for preparation of hydrogen halides
Chlorine NaCl(s) + H2SO4(aq)  HCl(g) + NaHSO4(aq)
NaBr(s) + H2SO4(aq)  HBr(g) + NaHSO4(aq)
Bromine
HBr(g) + H2SO4(aq)  Br2(g) + SO2(g) + H2O(l)
NaI(s) + H2SO4(aq)  HI(g) + NaHSO4(aq)
Iodine
HI(g) + H2SO4(aq)  I2(g) + SO2(g) + H2O(l)
HI(g) + H2SO4(aq)  I2(g) + H2S(g) + H2O(l)

11
...
2 Oxidising Ability
 Halogens have high electron affinity (they gain electrons
easily) hence they are good oxidising agents
 Oxidising ability decreases down the group because
electron affinity decreases as atomic size increases
...
3 Reaction of Elements with Hydrogen
X2(g) + H2(g)  2HX(g)
Product
Reaction Description
HF
Reacts explosively in all conditions
HCl
Reacts explosively in sunlight
HBr
Reacts slowly on heating
HI
Forms an equilibrium mixture on heating
 Thermal stability of halogen hydrides decreases down
the group because:
o Size of halogen atom increases
o ∴ nuclear attraction decreases
o The H – X bond becomes longer and weaker
o Thus less energy needed to break the bond
 Bond energies decrease down the group

 Fluorine:
o To make chlorofluorocarbon (CFCs)
o As fluoride in toothpaste
o To make polytetrafluoroethylene (PTFE) – non sticking
coating in pots and pans
 Bromine and Iodine: manufacture of photographic films
 Chlorine:
o In bleaches
o To make PVC and chlorofluorocarbon (CFCs)
o As solvents
 Use of chlorine in water purification:
o The oxidising power of chlorine is used in treatment of
water to kill bacteria
Cl2(aq) + H2O(l)  HCl(aq) + HClO(aq)
HClO(aq)  HCl(aq) + O
o This disproportionation reaction produces reactive
oxygen atoms which kill bacteria

12
...
1 Lack of Reactivity of Nitrogen

11
...
Silver Ions
Ag+(aq) + X-(aq)  AgX(s)
Halide
With Silver
With dilute
With conc
...
ammonia aq
...

ppt
...

ppt
...

 The solubility of these ppts
...
aq
...

 If ppt
...

 It reacts only under extreme temperature or pressure or
in presence of catalyst
...
2 Ammonium
 Lone pair of e-s of nitrogen forms a coordinate bond
with the H+ ion
 Formation: NH3(g) + H+  NH4+
 Shape: tetrahedral
 Bond angle: 109
...
INTRODUCTION TO ORGANIC CHEMISTRY

Displacement of ammonia from its salts:
Any
Ammonium
Salt

+

Any
Base

warm
→

Ammonia
Gas

+ Salt + Water

12
...
4 Eutrophication
 Nitrate fertilisers leach into rivers and lakes after rain
 Water plants grow more than usual
 They block sunlight and kill plants underneath
 Bacteria/fungi decompose remains using the O2
 Fish and other creatures die from oxygen starvation

12
...
and pressure
 Catalytic convertors: exhaust gases passed through
catalytic convertors containing a catalyst (platinum/
palladium/nickel) helping to reduce oxides to nitrogen
...
6 Pollution
Acid Rain:
SO3 + H2O  H2SO4
2NO2 + H2O  HNO3 + HNO2 or NO2 + H2O + ½O2  HNO3
 Damages trees & plants, kills fish and other river life,
buildings, statues and metal structures
Combustion Pollutants:
 Nitrogen oxide (NO): formed by reaction of N2 and O2 in
the engine, forms acid rain and respiratory problems
 Carbon monoxide (CO): source: incomplete combustion
of hydrocarbon fuel, toxic effect on haemoglobin

 Organic chemistry: study of hydrocarbons and their
derivatives
 Carbon can form a variety of compounds because:
o Carbon is tetravalent
o Carbon-carbon bonds can be single, double or triple
o Atoms can be arranged in chains, branches and rings
 Homologous series: a series of compounds of similar
structures in which:
o contain the same functional group
o all share same general formula
o formula of homologue differs from neighbour by CH2
o similar chemical properties
o gradual change in physical properties as Mr increases
 Functional group: an atom or group of atoms in an
organic molecule that determine the characteristic
reactions of a homologous series
...
1 Hybridization
 Hybridisation: mixing up of different atomic orbitals
resulting in new orbitals of equal energy
...
7 Food Preservation
 SO2 is used by itself or as a sulphite to preserve food
SO2 + H2O  H2SO3(aq)
 SO2 & suphites inhibit growth of bacteria, yeasts, etc
...

 Used to prevent spoilage of dried fruit, dehydrated
vegetables and fruit juices
...
2 Classes of Compound
Organic Family

Suffix

Example

-ane

Methane

-ene

Ethene

Alkanes

Alkenes
halo- … -ane

Chloroethane

Halogenoalkanes
-ol

Methanol

-al

Methanal

-one

Propanone

-oic

Methanoic acid

Alcohols

Aldehydes

Ketones

Carboxylic Acid

-oate

Methyl ethanoate

Esters
-amine

Methylamine

-nitrile

Ethyl nitrile

Amines

Nitriles
Page 18 of 27

CIE AS LEVEL- CHEMISTRY [9701]
13
...
7 Types of Reaction

Molecular Formula
C6H14

13
...
g
...
5 Breaking of Covalent Bonds
Homolytic Fission:
 Two atoms sharing e- pair of similar electro-tivity
 When bond breaks, each atom takes one e- from pair of
electrons forming free radicals
 Free radicals: electrically neutral atoms or group of
atoms with unpaired electrons  very reactive
 Free radical reaction catalysed by heat or light
Heterolytic Fission:
 Two atoms sharing e- pair are of different electro-tivity
 When bond breaks, one of the bonded atoms takes both
bonding e-s
 Results in formation of +ve and –ve ions
 If +ve charge on C, its called carbocation or carbonium
 If –ve charge on C, its called carbanion
Note: homolytic fission require less energy than heterolytic

 Addition reaction: single product formed
o Electrophilic addition (alkenes)
o Nucleophilic addition (carbonyl compounds)
 Substitution reaction: two products formed
o Nucleophilic substitution (halogenoalkanes)
o Free radical substitution (alkanes)
 Elimination reaction: more than one product formed,
small molecule removed from reactant (alcohols and
halogenoalkanes)
 Hydrolysis reaction: breaking down of molecule by
water, sped up by acid or alkali (esters and alkenes)

13
...
9 Shapes of Ethane and Ethene
Ethane

sp3 bonds
all sigma bonds

Ethene

Planar Shape
H – C – H bond = 120o
Benzene

13
...
6 Types of Reagents

ISOMERS
-

Nucleophilic reagent (nucleophile): donator of pair of e
 Must have lone pair of e-s
 Attack centre of +ve charge (positive pole)
 Reaction with nucleophile called nucleophilic reactions
 Examples: CH-, Cl-, NH3, H2O, CN-

Structural: molecules that have the
same molecular formula, but have a
different arrangement of the atoms

Page 19 of 27

Chain

Position

Functional

Stereo: molecules that have same
structure, but different spatial
arrangement of atoms in 3D space
Geometric

Optical

CIE AS LEVEL- CHEMISTRY [9701]
Note:
 Straight chain alkanes have higher b
...
than branched
 Branching makes molecule more spherical  reduces
contact points  VDW forces decreases

13
...
12 Position Isomers
 Isomers differ in position of substituent atoms or group
or the functional group
 Same chemical properties but slightly different physical
 Example:

But-1-ene

But-2-ene

13
...

Alcohol & Ether
Aldehyde & Ketone
Carboxylic acid &
Ester

13
...
of optical isomers in a molecule containing 𝑛 chiral
carbons = 2 𝑛

14
...
1 Properties
Generally unreactive:
 All C–C bonds single; alkanes = saturated hydrocarbons
 Non-polar ∴ no center of charge to act as either
nucleophile or electrophile ∴ cannot attract polar
reagents like acids, bases, metals or oxidizing agents
Physical properties:
 The volatility of the alkanes decreases and m
...
p
increases as number of carbon atoms increases
 Reason: increasing Van der Waals forces

14
...
14 Geometric (cis/trans) Isomers
 Shown only by alkenes
 Arises due to restriction of double bond
 Only possible when each carbon has 2 different groups
 cis-trans isomers have different b
...

 cis isomers have higher dipole
 trans isomer of symmetrical alkene has zero dipole

 Used as fuel because they burn in oxygen to given out
large amounts of energy
 Alkanes kinetically stable in presence of O2; combustion
occurs when necessary amount of Ea supplied
 Reaction occurs only in gas phase
 Complete: carbon dioxide + water
 Incomplete: carbon monoxide + carbon (soot) + water
 General Equation of Hydrocarbon Combustion:
𝑦
𝑦
𝐶 𝑥 𝐻 𝑦 + (𝑥 + ) 𝑂2 → 𝑥𝐶𝑂2 + 𝐻2 𝑂
4
2

14
...
7 Electrophilic Addition Mechanism

𝐶𝐻3 ⋅ +𝐶𝑙2 → 𝐶𝐻3 𝐶𝑙 + 𝐶𝑙 ⋅

o This can then react with another 𝐶𝑙2 and process
repeats if sufficient 𝐶𝑙2 present until all 𝐻 are replaced
 Termination:
o Reaction ends when 2 free radicals collide & combine
𝐶𝐻3 ⋅ +𝐶𝑙 ⋅→ 𝐶𝐻3 𝐶𝑙
𝐶𝐻3 ⋅ +𝐶𝐻3 ⋅→ 𝐶2 𝐻6
 Products: forms large amounts of CH3Cl and HCl and
small amount C2H6; separated by fractional distillation
 Products and free radicals differ due to:
o Halogen used: bromine requires more light
o Alkane used: ↑ no
...
8 Carbocations

14
...
p
...
6 Alkenes
 Unsaturated hydrocarbons
 Contain at least one C=C double bond
 General formula: CnH2n (like cycloalkanes)
 Source of alkenes:
o Cracking alkanes
o Dehydration of alcohols
 More reactive than alkanes due to presence of double
bond; pi electrons loosely and more susceptible to
attacks by e- deficient groups like electrophiles
 Alkenes combust completely  carbon dioxide + water
 Give energy but not used as fuels; have other uses

14
...
5 Hydrocarbons as Fuels

 Markovnikov’s principle: an electrophile adds to an
unsymmetrical alkene so that the most stable
carbocation is formed as an intermediate
 Hydrogen binds to carbon with more hydrogens
 Inductive effect of alkyl groups:
o Alkyl groups donate e- to the ring
o Producing a positive inductive effect
o A larger alkyl group has a weaker inductive effect

HydroHalogenation
halogenation

 Breaking of large less useful alkanes into useful, more
energy value smaller products using heat & catalyst
 Products:
smaller alkanes and alkenes or
smaller alkenes and hydrogen gas
 Thermal cracking: high temp
...
& catalyst

Page 21 of 27

Alkene + H2  Alkane
 Reagent: H2(g)
 Condition:
o Catalyst: Nickel
o Temp
...
: 2 atm
...
t
...
/dark
Alkene + Hydrohalogen  Halogenoalkane
 Reagent: Hydrohalogen(g)
 Condition: r
...
p
...
: 300oC
o Press
...
10 Oxidation of Alkenes
 Both oxidation and addition to double bond involved
 KMnO4 changes from pink to colourless
With Cold Dil
...
g
...
HALOGEN DERIVATIVES
15
...
Acidified KMnO4/H+
 Leads to the rupture of the double bond
 Two compounds are formed
 Products formed depend on alkene

Secondary 2o

SN2

Tertiary 3o

SN1

Decrease


Polar Nature
Fluoro
Chloro
Bromo
Iodo

Electro-tivity
decreases
down group

Bond Energy

Reactivity

Increases


15
...
3 Nucleophilic Substitution Mechanism

14
...

 The 𝛿 + carbocation is easily susceptible to attack by a
nucleophile
SN1 Mechanism:

 Unimolecular – only one molecule involved in 1st step
 Tertiary halogenoalkanes

Page 22 of 27

CIE AS LEVEL- CHEMISTRY [9701]

 Bimolecular – two molecules involved in 1st step
 Primary and secondary halogenoalkanes

 Reagent: ethanolic NaOH or KOH
 Conditions: temp
...


15
...
7 Uses of Halogenoalkanes

SN2 Mechanism:

R – X + OH  R – OH + X
 Reagent: strong alkali; NaOH(aq) or KOH(aq)
 Condition: heat/reflux
 Fluoroalkanes are not hydrolysed because the
C – F bond is too strong
 Ease of hydrolysis increases:
Primary < Secondary < Tertiary
 Tertiary halogenoalkanes can be hydrolysed
without alkali
 Note: if any Cl- or Br- ions present in NaOH(aq),
these ions will interfere with reaction
R – X + CN-  RCN + X Reagent: KCN or NaCN in ethanol
 Condition:
o Solvent: Ethanol
o Heat/Reflux
 Reaction forms a C – C bond therefore no
...
ammonia used, HX
reacts with it forming NH4X

Primary Amines

Nitrile (cyanide)

Hydrolysis

-

-

15
...

 Uses:
o As propellants  in aerosol cans
o As solvents  in dry-cleaning
o As refrigerant  for freezers and fridges
o Fire extinguishers, insecticides and pesticides

15
...

 In stratosphere, high energy U
...
HYDROXY COMPOUNDS
16
...
6 Elimination Reaction
R – X + OH-  Alkene + X- + H2O
Mechanism:
 Source of Alcohols:
o Hydration of alkenes
o Fermentation
Page 23 of 27

Tertiary 3o

CIE AS LEVEL- CHEMISTRY [9701]
16
...
t
...
p
...
p
...
p
...
p
...
e
...
g
...
3 Reaction with Sodium

16
...
6 Dehydration of Alcohols

R – OH + Na(l)  RO Na + ½ H2(g)
 Type of reaction: acid-base
 Reagent used: liquid sodium metal
 Reactivity of alcohols decreases with increasing chain
lengths of hydrocarbon
 Reaction less vigorous than that of Na and water which
shows water is a stronger acid than alcohol
-

Properties of Esters:
 Esters are volatile compounds – no H-bonds so low m
...

 Polar molecules – soluble in organic solvents
 Sweet, fruity smelling liquids
 Many occur naturally e
...
as fats, oils & flavours in fruits
 Used in food flavourings and perfumes and as solvents

+

Alcohol(l)  Alkene + H2O(l)
Condition
Type of Reaction
or
Conc
...
4 Reaction with Carboxylic Acids
 Adjacent carbon to carbon with OH must have at least
one hydrogen (tertiary cannot undergo dehydration)

Reagent
R-COOH

Condition
Heat-reflux
Conc
...
7 Halogenation
 Type of Reaction: Nucleophilic Substitution
R – OH  R – X
Producing:
Alkyl Chlorides
NaBr + H2SO4(aq)  HBr
P + Br2 –warm PBr3
P + I2 –warm PI3

Alkyl Bromides
Alkyl Iodide

R – OH +

Forming Reagent

Reactions
Conc
...
8 Oxidation of Alcohols
 Reagent: Oxidising agents
Reagent
Type of Reaction
Acidified K2Cr2O4 Acidified KMnO4
Oxidation
Orange to Green Pink to Colourless
Primary Alcohol
R-CH2-OH

Secondary Alcohol
R-CH(OH)-R

Condition
Zn + Heat/Reflux
r
...
p
Heat/Reflux
r
...
p
r
...
p

17
...
1 Nucleophilic Addition with HCN
Reagent

 If aldehyde needed, must distil
as soon as it forms
 Tertiary alcohols not oxidised because no hydrogens
attached to carbon with OH group so oxidising agent
colour does not change

16
...
To increase CN- conc
...
2 Reduction of Carbonyl Compounds
 Type of Reaction: nucleophilic addition (H- ions)
 Reducing agents:
o NaBH4 – sodium tetrahydrioborate
o LiAlH4 – lithium aluminium hydride
o H2/Pt or Ni
Aldehydes ⟹ 1o Alcohols
Ketones ⟹ 2o Alcohols
R-CHO + 2[H]  RCH2OH R-CO-R + 2[H]  R-CH(OH)-R

18
...
p
...
p
...
1 Formation of Carboxylic Acids
 From alcohols: complete oxidation of primary alcohols
 From aldehydes: oxidation of aldehydes
 From nitriles: acid/base hydrolysis of a nitrile

17
...
2 Formation of Salts
 Heterolytic fission of the hydroxyl bond (-OH)
 Salts called carboxylates
 It is a nucleophilic addition & condensation/elimination
 Forms: red/orange ppt
...
p
...
can be used to identify individual
aldehydes and ketones
Tests Given only by Aldehydes:
Tollen’s Reagent
Solution of AgNO3 + aq
...

2+
Cu reduced to Cu(I) oxide and –CHO oxidised to acid
2Cu2+ + RCHO  2Cu+ + RCOOH- + H+

19
...
1 Infra-red Spectroscopy
 This is when a sample being analysed is irradiated with
electromagnetic waves in the infra-red region of the
electromagnetic spectrum
...
2 Monitoring Air Pollution
 IR spectroscopy identifies particular bonds in a
molecule, and so each pollutant will show a different
pattern of absorptions – this allows the identification of
the pollution
 It is also possible to measure the concentration of each
pollutant with the different amounts of absorption

Page 27 of 27



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