Topic 9 - Metals

9.1 Properties of metals
9.2 Reactivity series
9.3 Extraction of metals
9.4 Iron
9.5 Aluminium

9.1 Properties of metals
(a) describe the general physical properties of metals (as solids having high melting and boiling points; malleable; good conductors of heat and electricity) in terms of their structure

(b) describe an alloy as a mixture of a metal with another element, e.g. brass; stainless steel
(c) identify representations of metals and alloys from diagrams of structures
(d) explain why alloys have different physical properties from their constituent elements

9.2 Reactivity series
(a) place in order of reactivity: aluminium (see also 9.5(b)), calcium, copper, (hydrogen), iron, lead, magnesium, potassium, silver, sodium and zinc by reference to
(i) the reactions, if any, of the metals with water, oxygen, steam and dilute hydrochloric acid,

(ii) the reduction, if any, of their oxides by carbon and/or by hydrogen
(b) describe the reactivity series as related to the tendency of a metal to form its positive ion, illustrated by its reaction with
(i) the aqueous ions of the other listed metals
(ii) the oxides of the other listed metals

(c) deduce the order of reactivity from a given set of experimental results

(d) describe the action of heat on the carbonates of the listed metals and relate thermal stability to the reactivity series

9.3 Extraction of metals

(a) describe the ease of obtaining metals from their ores by relating the elements to their positions in the reactivity series

(b) describe metal ores as a finite resource and hence the need to recycle metals

(c) discuss the social, economic and environmental advantages and disadvantages of recycling metals, e.g. aluminium and copper

9.4 Iron

(a) describe and explain the essential reactions in the extraction of iron using haematite, limestone and coke in the blast furnace

(b) describe steels as alloys which are a mixture of iron with carbon and often other metals and how controlled use of these additives changes the properties of the iron, e.g. high carbon steels are strong but brittle whereas low carbon steels are softer and more easily shaped

(c) state the uses of mild steel (e.g. car bodies; machinery) and stainless steel (e.g. chemical plant; cutlery; surgical instruments)

(d) describe the essential conditions for the corrosion (rusting) of iron as the presence of oxygen and water; prevention of rusting can be achieved by placing a barrier around the metal (e.g. painting; greasing; plastic coating; galvanising)

(e) describe the sacrificial protection of iron by a more reactive metal in terms of the reactivity series where the more reactive metal corrodes preferentially (e.g. underwater pipes have a piece of magnesium attached to them)

9.5 Aluminium

(a) outline the manufacture of aluminium from pure aluminium oxide dissolved in cryolite (starting materials and essential conditions, including identity of electrodes should be given together with equations for the electrode reactions but no technical details or diagrams are required)

(b) explain the apparent lack of reactivity of aluminium

(c) state the uses of aluminium and relate the uses to the properties of this metal and its alloys, e.g. the manufacture of aircraft; food containers; electrical cables

Topic 6 - Chemical Reactions

6.1 Rate of reaction
6.2 Redox
6.3 Reversible reactions

6.1 Rate of reaction
(a) describe the effect of concentration, pressure, particle size and temperature on the rates of reactions and explain these effects in terms of collisions between reacting particles

(b) define the term catalyst and describe the effect of catalysts (including enzymes) on the rates of reactions

(c) explain how pathways with lower activation energies account for the increase in rates of reactions

(d) state that transition elements and their compounds act as catalysts (see 8.3) in a range of industrial processes and that enzymes are biological catalysts

(e) suggest a suitable method for investigating the effect of a given variable on the rate of a reaction

(f) interpret data obtained from experiments concerned with rate of reaction

6.2 Redox

(a) define oxidation and reduction (redox) in terms of oxygen/hydrogen gain/loss

(b) define redox in terms of electron transfer

(c) identify redox reactions in terms of oxygen/hydrogen, and/or electron, gain/loss (calculation of oxidation numbers is not required)

(d) describe the use of aqueous potassium iodide in testing for oxidising agents and acidified potassium manganate(VII) in testing for reducing agents from the resulting colour changes

6.3 Reversible reactions

(a) describe the idea that some chemical reactions can be reversed by changing the reaction conditions

(b) describe the idea that some reversible reactions can reach dynamic equilibrium and predict and explain the effect of changing the conditions (see 7.3(b) and 7.3(c))

Topic 10 - Atmosphere and environment

10.1 Air

(a) describe the volume composition of gases present in dry air as 78% nitrogen, 21% oxygen and the remainder being noble gases (with argon as the main constituent) and carbon dioxide

(b) describe the separation of oxygen, nitrogen and the noble gases from liquid air by fractional distillation

(c) state the uses of oxygen (e.g. in making steel; oxygen tents in hospitals; in welding)

(d) name some common atmospheric pollutants (e.g. carbon monoxide; methane; nitrogen oxides (NO and NO₂); ozone; sulfur dioxide; unburned hydrocarbons)

(e) state the sources of these pollutants as

• (i) carbon monoxide from incomplete combustion of carbon-containing substances
• (ii) methane from bacterial decay of vegetable matter
• (iii) nitrogen oxides from lightning activity and internal combustion engines
• (iv) ozone from photochemical reactions responsible for the formation of photochemical smog
• (v) sulfur dioxide from volcanoes and combustion of fossil fuels
• (vi) unburned hydrocarbons from internal combustion engines

A presentation done by students of grade 11.

(f) describe the reactions used in possible solutions to the problems arising from some of the pollutants named in (d)

• (i) the redox reactions in catalytic converters to remove combustion pollutants

• (ii) the use of calcium carbonate to reduce the effect of ‘acid rain’ and in flue gas desulfurisation

Another presentation done by students of grade 11

(g) discuss some of the effects of these pollutants on health and on the environment

• (i) the poisonous nature of carbon monoxide
• (ii) the role of nitrogen dioxide and sulfur dioxide in the formation of ‘acid rain’ and its effects on respiration and buildings

(h) discuss the importance of the ozone layer and the problems involved with the depletion of ozone by reaction with chlorine-containing compounds, chlorofluorocarbons (CFCs)

(i) *describe the carbon cycle in simple terms, to include

• (i) the processes of combustion, respiration and photosynthesis
• (ii) how the carbon cycle regulates the amount of carbon dioxide in the atmosphere

Here is a presentation done by students of grade 11.

(j) state that carbon dioxide and methane are greenhouse gases and may contribute to global warming, give the sources of these gases and discuss the possible consequences of an increase in global warming

10.2 Water

(a) state that water from natural sources contains a variety of dissolved substances

• (i) naturally occurring (mineral salts; oxygen; organic matter)
• (ii) pollutant (metal compounds; sewage; nitrates from fertilisers; phosphates from fertilisers and detergents; harmful microbes)

(b) discuss the environmental effects of the dissolved substances named in (a)

• (i) beneficial, e.g. oxygen and mineral salts for aquatic life
• (ii) pollutant, e.g. hazards to health; eutrophication

Here is another presentation by grade 11 students.

(c) outline the purification of the water supply in terms of

• (i) filtration to remove solids
• (ii) use of carbon to remove tastes and odours
• (iii) chlorination to disinfect the water

(d) state that seawater can be converted into drinkable water by desalination

Topic 5 - Energy From Chemicals

(a) describe the meaning of enthalpy change in terms of exothermic (ΔH negative) and endothermic (ΔH positive) reactions
Please read p302-303

(b) *represent energy changes by energy profile diagrams, including reaction enthalpy changes and activation energies (see 6.1(c))

Please read p309-311

(c) describe bond breaking as an endothermic process and bond making as an exothermic process

Please read p306-307

(d) *explain overall enthalpy changes in terms of the energy changes associated with the breaking and making of covalent bonds

Please read p307-309

(e) describe combustion of fuels as exothermic, e.g. wood, coal, oil, natural gas and hydrogen

Please read p311

(f) describe hydrogen, derived from water or hydrocarbons, as a potential fuel for use in future, reacting with oxygen to generate electricity directly in a fuel cell (details of the construction and operation of a fuel cell are not required) and discuss the advantages and disadvantages of this

Please read p313

(g) name natural gas, mainly methane, and petroleum as sources of energy

Please read p311

(h) describe petroleum as a mixture of hydrocarbons and its separation into useful fractions by fractional distillation

Please read p381-382

(i) name the following fractions and state their uses

• (i) petrol (gasoline) as a fuel in cars
• (ii) naphtha as feedstock for the chemical industry
• (iii) paraffin (kerosene) as a fuel for heating and cooking and for aircraft engines
• (iv) diesel as a fuel for diesel engines
• (v) lubricating oils as lubricants and as a source of polishes and waxes
• (vi) bitumen for making road surfaces

Please read p382

(j) describe photosynthesis as the reaction between carbon dioxide and water in the presence of chlorophyll, using sunlight (energy) to produce glucose and explain how this can provide a renewable energy source.

Please read p371-372

Topic 8 The Periodic Table

8.1 Periodic trends
(a) describe the Periodic Table as an arrangement of the elements in the order of increasing proton (atomic) number
Please read p284
(b) *describe how the position of an element in the Periodic Table is related to proton number and electronic structure
(c) *describe the relationship between Group number and the ionic charge of an element 
(d) explain the similarities between the elements in the same Group of the Periodic Table in terms of their electronic structure

(e) describe the change from metallic to non-metallic character from left to right across a period of the Periodic Table Please read p285

(f) *describe the relationship between Group number, number of valency electrons and metallic/non-metallic character
Please read p286-287

(g) *predict the properties of elements in Group I, VII and the transition elements using the Periodic Table
Please read p289-293

8.2 Group properties

(a) describe lithium, sodium and potassium in Group I (the alkali metals) as a collection of relatively soft, low-density metals showing a trend in melting point and in their reaction with water
Please read p289-291

(b) describe chlorine, bromine and iodine in Group VII (the halogens) as a collection of diatomic non-metals showing a trend in colour, state and their displacement reactions with solutions of other halide ions

Please read p292-294

(c) describe the elements in Group 0 (the noble gases) as a collection of monatomic elements that are chemically unreactive and hence important in providing an inert atmosphere, e.g. argon and neon in light bulbs; helium in balloons; argon in the manufacture of steel

Please read p295-296

(d) describe the lack of reactivity of the noble gases in terms of their electronic structures

8.3 Transition elements

(a) describe the central block of elements (transition metals) as metals having high melting points, high density, variable oxidation state and forming coloured compounds

(b) state the use of these elements and/or their compounds as catalysts, e.g. iron in the Haber process; vanadium(V) oxide in the Contact process; nickel in the hydrogenation of alkenes, and how catalysts are used in industry to lower energy demands and hence are economically advantageous and help conserve energy sources

Topic 4 - Electrolysis

(a) *describe electrolysis as the conduction of electricity by an ionic compound (an electrolyte), when molten or dissolved in water, leading to the decomposition of the electrolyte
(b) *describe electrolysis as evidence for the existence of ions which are held in a lattice when solid but which are free to move when molten or in solution
(c) describe, in terms of the mobility of ions present and the electrode products, the electrolysis of molten lead bromide, using inert electrodes
(d) predict the likely products of the electrolysis of a molten compound
(e) apply the idea of selective discharge (linked to the reactivity series for cations, see 9.2) to deduce the electrolysis of concentrated aqueous sodium chloride,

aqueous copper(II) sulfate

and dilute sulfuric acid using inert electrodes

(f) predict the likely products of the electrolysis of an aqueous electrolyte, given relevant information

(g) construct equations for the reactions occurring at each electrode during electrolysis

(h) *describe the electrolysis of purified aluminium oxide dissolved in molten cryolite as the method of extraction of aluminium (see 9.5(a))

(i) *describe the electrolysis of aqueous copper(II) sulfate with copper electrodes as a means of purifying copper

(j) *describe the electroplating of metals, e.g. copper plating, and recall one use of electroplating

(k) describe the production of electrical energy from simple cells (i.e. two electrodes in an electrolyte) linked to the reactivity series (see 9.2)

Topic 7 - The Chemistry and Uses of Acids, Bases and Salts

7.1 The characteristic properties of acids and bases
(a) describe the meanings of the terms acid and alkali in terms of the ions they contain or produce in aqueous solution and their effects on Universal Indicator paper

(b) describe how to test hydrogen ion concentration and hence relative acidity using Universal Indicator paper and the pH scale

(c) describe the characteristic properties of acids as in reactions with metals, bases and carbonates
(d) describe qualitatively the difference between strong and weak acids in terms of the extent of ionisation

(e) describe neutralisation as a reaction between hydrogen ions and hydroxide ions to produce water, H⁺ + OH^– → H₂O

(f) describe the importance of controlling the pH in soils and how excess acidity can be treated using calcium hydroxide
(g) describe the characteristic properties of bases in reactions with acids and with ammonium salts
(h) classify oxides as acidic, basic or amphoteric, based on metallic/non-metallic character
7.2 Preparation of salts

(a) *describe the techniques used in the preparation, separation and purification of salts as examples of some of the techniques specified in Section 1.2(a)
(methods for preparation should include precipitation and titration together with reactions of acids with metals, insoluble bases and insoluble carbonates)

(b) describe the general rules of solubility for common salts to include nitrates, chlorides (including silver and lead), sulfates (including barium, calcium and lead), carbonates, hydroxides, Group I cations and ammonium salts

(c) suggest a method of preparing a given salt from suitable starting materials, given appropriate information

7.3 Properties and uses of ammonia

(a) describe the use of nitrogen, from air, and hydrogen, from cracking oil, in the manufacture of ammonia

(b) state that some chemical reactions are reversible (e.g. manufacture of ammonia)

(c) *describe and explain the essential conditions for the manufacture of ammonia by the Haber process

(d) describe the use of nitrogenous fertilisers in promoting plant growth and crop yield

(e) compare nitrogen content of salts used for fertilisers by calculating percentage masses

(f) describe eutrophication and water pollution problems caused by nitrates leaching from farm land and explain why the high solubility of nitrates increases these problems

(g) describe the displacement of ammonia from its salts and explain why adding calcium hydroxide to soil can cause the loss of nitrogen from added nitrogenous fertiliser

7.4 Sulfuric acid

(a) describe the manufacture of sulfuric acid from the raw materials sulfur, air and water in the Contact process

(b) state the use of sulfur dioxide as a bleach, in the manufacture of wood pulp for paper and as a food preservative (by killing bacteria)

(c) state the uses of sulfuric acid in the manufacture of detergents and fertilisers, and as a battery acid

Bonding

2.4 Ionic bonding
(a) *describe the formation of ions by electron loss/gain in order to obtain the electronic configuration of an inert gas
Read p87-92
(b) *describe the formation of ionic bonds between metals and non-metals, e.g. NaCl; MgCl₂
Read p93-94

(c) *state that ionic materials contain a giant lattice in which the ions are held by electrostatic attraction, e.g. NaCl (candidates will not be required to draw diagrams of ionic lattices)
Read p96
(d) deduce the formulae of other ionic compounds from diagrams of their lattice structures, limited to binary compounds
Read p94-95
(e) relate the physical properties (including electrical property) of ionic compounds to their lattice structure
Read p97-99

2.5 Covalent bonding
(a) *describe the formation of a covalent bond by the sharing of a pair of electrons in order to gain the electronic configuration of an inert gas
Read p102

(b) describe, using ‘dot-and-cross’ diagrams, the formation of covalent bonds between non-metallic elements, e.g. H₂; Cl₂; O₂; HCl; N₂; H₂O; CH₄; C₂H₄; CO₂
Read p102-105
(c) deduce the arrangement of electrons in other covalent molecules
Read p106
(d) relate the physical properties (including electrical properties) of covalent compounds to their structure and bonding
Read p106-112

2.6 Metallic bonding
(a) *describe metals as a lattice of positive ions in a ‘sea of electrons’
Read p113

(b) *relate the malleability of metals to their structure and the electrical conductivity of metals to the mobility of the electrons in the structure
Read p113

Topic 2 - The Particulate Nature Of Matter

2.1 Kinetic particle theory
(a) *describe the solid, liquid and gaseous states of matter and explain their interconversion in terms of the kinetic particle theory and of the energy changes involved
Read p1-15
(b) *describe and explain evidence for the movement of particles in liquids and gases (the treatment of Brownian motion is not required)
Read p16-20
(c) explain everyday effects of diffusion in terms of particles, e.g. the spread of perfumes and cooking aromas; tea and coffee grains in water
Read p16-20
(d) *state qualitatively the effect of molecular mass on the rate of diffusion and explain the dependence of rate of diffusion on temperature
Read p16-20
(e) state qualitatively and explain the effects of temperature and pressure on the volumes of gases
Read p16-20
2.2 Atomic structure
(a) state the relative charges and approximate relative masses of a proton, a neutron and an electron
Read p74-77
(b) *describe, with the aid of diagrams, the structure of an atom as containing protons and neutrons (nucleons) in the nucleus and electrons arranged in shells (energy levels) (no knowledge of s, p, d and f classification will be expected; a copy of the Periodic Table will be available in Papers 1 and 2)
Read p76-77,79 
(c) define proton number and nucleon number Read p76
(d) interpret and use symbols such as ¹²₆C  Read p77
(e) define the term isotopes Read p78
(f) deduce the numbers of protons, neutrons and electrons in atoms and ions from proton and nucleon numbers Read p76-77
(g) state that some isotopes are radioactive Read p78

2.3 Structure and properties of materials
(a) describe the differences between elements, compounds and mixtures
Read p59-71
(b) *compare the structure of simple molecular substances, e.g. methane, iodine, with those of giant molecular substances, e.g. sand, diamond, graphite in order to deduce their properties
Read p106-110
(c) *compare the bonding and structures of diamond and graphite in order to deduce properties such as electrical conductivity, lubricating or cutting action (candidates will not be required to draw the structures)
Read p109-110
(d) deduce the physical and chemical properties of substances from their structures and bonding and vice versa

Topic 1 - Experimental Chemistry

It is expected that any course in chemistry will be based on experimental work. Teachers are encouraged to develop appropriate practical work for candidates to facilitate a greater understanding of the subject.

Candidates should be aware of the hazards and appropriate safety precautions to follow when handling the reagents mentioned in this section.

1.1 Experimental design
(a) name appropriate apparatus for the measurement of time, temperature, mass and volume, including burettes, pipettes, measuring cylinders and gas syringes
CM - Chapter 2 p23-29
Read the textbook and underline important points using the objective.
Watch the video clips which follow.

(b) suggest suitable apparatus, given relevant information, for a variety of simple experiments, including collection of gases and measurement of rates of reaction
CM - Chapter 2 p26-27
Read the textbook and underline important points using the objective
1.2 Methods of purification and analysis
(a) describe methods of purification by the use of a suitable solvent, filtration and crystallisation, distillation and fractional distillation, with particular references to the fractional distillation of crude oil, liquid air and fermented liquor
CM - Chapter 3 p40-54,
Crystallisation

Distillation - Watch the video clip

Fractional distillation

A little history of petroleum - in French

Fractional distillation - p381(crude oil),

p51(liquid air), p418 (fermented liquor).
Read the textbook and underline important points using the objective
You are explicitly asked not to imitate the character in the following video clip

(b) suggest suitable methods of purification, given information about the substances involved
CM - Chapter 3 p52 - Key ideas
(c) describe paper chromatography and interpret chromatograms including 
comparison with ‘known’samples and the use of Rf values
CM - Chapter 3 p36-39
Watch the video clip

(d) explain the need to use locating agents in the chromatography of colourless compounds
CM - Chapter 3 p39
Watch the video clip.

(e) deduce from the given melting point and boiling point the identities of substances and their purity
CM - Chapter 3 p32-35
Watch the following video clip

(f) explain that the measurement of purity in substances used in everyday life, e.g. foodstuffs and drugs, is important

CM - Chapter 3 p33

1.3 Identification of ions and gases
(a) describe the use of aqueous sodium hydroxide to identify the following aqueous cations: aluminium, ammonium, calcium,  chromium(III),  copper(II), iron(II), iron(III) and zinc (formulae of complex ions are not required)

CM - Chapter 12 p205 - 206
Watch the video clips

Analysis of calcium ions

and aqueous ammonia to identify the following  aqueous cations: aluminium, ammonium, calcium, chromium (III), copper(II), iron(II), iron(III) and zinc (formulae of complex ions are not required)

CM - Chapter 12 p205 -206

Watch the video clip

(b) describe tests to identify the following anions: carbonate (by the addition of dilute acid and subsequent use of limewater); chloride (by reaction of an aqueous solution with nitric acid and aqueous silver nitrate); iodide (by reaction of an aqueous solution with 
nitric acid and aqueous silver nitrate); nitrate (by reduction with aluminium and aqueous sodium hydroxide to ammonia and subsequent use of litmus paper) and sulfate (by reaction of an aqueous solution with nitric acid and aqueous barium nitrate)
CM - p 207
Watch the following video clips

Analysis of iodide ions

(c) describe tests to identify the following gases: 

ammonia (using damp red litmus paper); 
carbon dioxide (using limewater); 
chlorine (using damp litmus paper); 
hydrogen (using a burning splint); 
oxygen (using a glowing splint) and 
sulfur dioxide (using acidified potassium dichromate(VI))

(d) describe a chemical test for water

Welcome To The Chemistry Blog

First things first.
You will have to become familiar with your syllabus - code number 5070 for 2014. You will need it for study and revision purposes
Click here to view and download it.
I hope you will enjoy the time you spend here to learn the subject, but also become familiar with learning online.

Assessment at a glance
For the Cambridge O Level in chemistry, candidates take three components: Paper 1 and Paper 2 and  Paper 4.
Paper 1: Multiple Choice 1 hour
40 compulsory multiple-choice questions. A copy of the Periodic Table is provided as part of this paper. 40 marks

Paper 2: Theory 1 hour 30 minutes
This paper has two sections.
Section A has a small number of compulsory, structured questions of variable 
mark value. 45 marks in total are available for this section.
Section B has four questions to choose from and candidates must answer three. Each question is worth 10 marks.
A copy of the Periodic Table is provided as part of this paper. 75 marks

Paper 4: Alternative to Practical 1 hour
A written paper of compulsory short-answer and structured questions designed to test familiarity with laboratory practical procedures.
Qualitative Analysis Notes are not provided. 
60 marks scaled to a mark out of 30
Textbook used: GCE 'O' Level Chemistry Matters - Tan Yin Toon, Chen Ling Kwong, John Sadler, Emily Clare (Marshall Cavendish)
In this blog the textbook will be referred to as CM standing for Chemistry Matters.
Watch the following video clip