Doc Brown's Chemistry Unofficial Support for

Zimbabwe O level chemistry syllabus 5071 specification

ZIMBABWE GENERAL CERTIFICATE OF EDUCATION (ZGCE)

ZIMBABWE SCHOOL EXAMINATIONS COUNCIL

(ZIMSEC O level chemistry examinations)

general [useful O Level chemistry revision notes] index

Note: Zimbabwe Advanced Level Chemistry help page

LET ME KNOW if this page is useful or not! via chem55555@hotmail.com

if this page isn't used very much and not proving useful, then there is no point in developing it further!

By following the specific links below you will find some useful information and use the sub-indexes of key words or headings at the top/bottom of each page to explore my site further for revision notes to help with Zimbabwe O level chemistry. To return to this Zimbabwe O level chemistry page click on the <== back on the browser link bar. All the syllabus-topic-unit titles are taken from the official Zimbabwe O level chemistry syllabus.  I do hope these O level chemistry revision notes pages will help you pass Zimbabwe's O level chemistry examination.

1 THE PARTICULATE NATURE OF MATTER  (physical states of matter Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) describe the states of matter and explain their inter-conversion in terms of the kinetic particle theory;

(b) describe evidence for the movements of particles in gases and liquids (the treatment of Brownian motion is not required);

(c) describe and explain diffusion;

(d) describe the dependence of rate of diffusion on molecular mass (treated qualitatively).

States of Matter - particle theory - gas, liquid & solid properties-behaviour, state changes

2 EXPERIMENTAL TECHNIQUES   (laboratory procedures Zimbabwe O Level Chemistry 5071)

2.1. Apparatus   (laboratory equipment Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) name appropriate apparatus for the measurement of time, temperature, mass and volume, including burettes, pipettes and measuring cylinders;

(b) design arrangement of apparatus, given information about the substances involved;

(c) describe the use of volumetric apparatus and indicators including methyl orange and screened methyl orange;

How to do titrations and calculations e.g. acid-alkali titrations (and diagrams of apparatus)

Dilution of solutions, apparatus

2.2. (a) Criteria of purity   (importance of testing for purity, chromatography Zimbabwe O Level Chemistry 5071)

You should be able to:

(i) describe paper chromatography and interpret chromatograms including comparison with ‘known’ samples and Rf values;

(ii) describe how chromatography techniques be applied to colourless substances (knowledge of the composition of particular locating agents is not required);

(iii) identify substances and test their purity by melting point and boiling point determination and by paper chromatography;

(iv) explain the importance of purity in substances in everyday life, e.g. in foodstuffs and drugs;

Definitions and criteria in chemistry eg atom, molecule, formula, element, compound, mixture, pure, impure etc.

Paper & thin layer chromatography (tlc)

2.2. (b) Methods of purification   (how can we purify materials? Zimbabwe O Level Chemistry 5071)

You should be able to:

(i) describe methods of purification by the use of a suitable solvent, filtration, crystallisation, distillation (including use of fractionating column) (refer to the fractional distillation of : crude oil, liquid air, fermented liquor);

(ii) suggest suitable purification techniques, given information about the substances involved.

Distillation - Simple and Fractional Distillation 

Filtration, evaporation, crystallisation, drying and decantation

3 ATOMS, ELEMENTS AND COMPOUNDS   (Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) state the relative charges and approximate relative masses o protons, neutrons and electrons;

(b) define proton (atomic) number and nucleon (mass) number;
(c) use and interpret such symbols as ;

(d) use proton number and the simple structure of atoms to explain the Periodic Table, with special references to the elements of proton number 1 to 20;

(e) define isotopes;

(f) state that some isotopes are radioactive;

(g) describe one medical, and one industrial, use of a radioactive isotope;

(h) describe the build-up of electrons in ‘shells’ and understand the significance of valency electrons and the noble gas electronic structures.

(The ideas of the distribution of electrons in s and p orbitals and in d block elements are not required)

(Note that a copy of the Periodic Table will be available in the examination in Paper 1 and Paper 2).
 

Atomic Structure - nucleus, electrons, isotopes etc.

Periodic Table Notes - section on electron structure

3.1. Bonding: the structure of matter  (Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) describe the differences between elements, compounds and mixtures and between metals and non-metals;

(b) describe alloys, such as brass, as mixture of a metal with other elements

Definitions and criteria in chemistry eg atom, molecule, formula, element, compound, mixture

Periodic Table Notes - an overview - section on comparing metals & non-metals

3.2. (a) Ions and ionic bonds   (Zimbabwe O Level Chemistry 5071)

You should be able to:

(i) describe the formation of ions by electrons loss or grain

(ii) describe the formations of ionic bonds between metallic and non-metallic elements, e.g. in NaCl, CaCl₂;

(iii) describe the lattice structure of sodium chloride

(iv) describe some ionic compounds as refractory materials, e.g. MgO as a lining in furnaces.

Introduction to Chemical Bonding

Ionic bonding and ionic compounds and their properties

3.2. (b) Molecule and covalent bonds   (Zimbabwe O Level Chemistry 5071)

(i) Be able to describe the formation of covalent bonds between non-metallic elements leading to the noble gas configuration, e.g. H₂, Cl₂, N₂, HCl, H₂O, CH₄, C₂H₄, CO₂ ??? it said C4H4CO2 on syllabus - printing error?

(ii) be able to deduce the electron arrangement in other covalent molecules;

(iii) be able to construct ‘dot and cross’ diagrams to show the valency electrons in covalent molecules

Introduction to Chemical Bonding

Covalent bonding and small molecules and their properties

3.2. (c) Macromolecules   (Zimbabwe O Level Chemistry 5071)

(i) Be able to describe the structure of macromolecules such as graphite, diamond, silica (SiO₂, silicon (IV) oxide, silicon dioxide) and poly(ethene)

(ii) Be able to describe the similarity in structure of diamond and silicon, diamond and silica (silicon (IV) oxide) and of their properties related to their structures.

Introduction to Chemical Bonding

Covalent bonding and giant structures and their properties and uses

Addition polymer structure - properties and uses including poly(ethene)

3.2. (d) Metallic bonding   (Zimbabwe O Level Chemistry 5071)

You should be able to describe metallic bonding as a lattice of positive ions in a ‘sea of electrons’ and explain the electrical conductivity and malleability of metals.

Introduction to Chemical Bonding

3.2. (e) Physical Properties   (Zimbabwe O Level Chemistry 5071)

You should be able to relate the volatility, solubility and electrical conductivity of a compound to its structure to its structure and bonding.

These ideas are covered in the individual sections above.

4 STOICHIOMETRY AND THE MOLE CONCEPT   (Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) state the symbols of the elements and formulae of the compounds mentioned in the syllabus.

Element symbol & name QUIZ - easier-pictorial  or  Element symbol & name QUIZ harder - no pictures!

Quiz on the naming and formula of chemical compounds

(b) deduce the formula of a simple compound from the relative numbers of atoms present and vice versa;

(c) determine the formula of a ionic compound from the charges on the ions present and vice versa;

(d) construct equations with state symbols, including ionic equations;

(e) deduce the balanced chemical equation for a chemical reaction, given relevant information;

Multiple Choice Quiz on balancing Symbol Chemical Equations with numbers

Number fill Quiz on completing symbol equations (Q1 Q2 Q3)

How to write word & balance symbol equations, work out formula and name compounds

(f) define relative atomic mass, Ar;

(g) define relative molecular mass, Mr, and calculate it as the sum of relative atomic masses;

What is relative atomic mass? (A_r) and calculating relative atomic mass

Relative atomic mass - type in answer QUIZ and Relative atomic mass - multiple choice QUIZ

Calculating relative formula/molecular mass (M_r) of a compound or element molecule

Type in answer quiz on relative formula mass and Multiple Choice quiz on relative formula mass

(h) use the mole concept to calculate empirical formulae and molecular formulae;

Introducing moles: The connection between moles, mass and formula mass

Introduction to moles type in answer QUIZ and Introduction to moles multiple choice QUIZ

Using moles to calculate empirical formula and deduce molecular formula of a compound/molecule (starting with reacting masses or % composition)

Empirical formula type in answer QUIZ using moles and Empirical formula multiple choice QUIZ using moles

(i) calculate stoichiometric reacting masses and volumes of gasses and solutions, solution concentration being expressed in g/dm³ and/or in mol/dm³; calculations involving the idea of limiting reactants may be set.

(Questions on the gas law and the conversion of gaseous volumes to different temperatures and pressures will not be set)

Reacting mass ratio calculations of reactants and products from equations

Type in answer QUIZ on reacting masses and Multiple choice QUIZ on reacting masses

Reacting gas volume ratios (ratio of gaseous reactants-products)

Reacting volumes type in answer QUIZ and  Reacting volumes multiple choice QUIZ

Molarity, volumes and solution concentrations (and diagrams of apparatus)

Molarity type in answer QUIZ and Molarity multiple choice QUIZ

(j) Calculate % yield and % purity

% purity of a product

% reaction yield and theoretical yield calculations, why never 100%

How much of a reactant is needed? calculation of quantities required, limiting quantities

5 ELECTRICITY AND CHEMISTRY   (Zimbabwe O Level Chemistry 5071)

Electrochemistry Notes  - an introduction to electrolysis,  theory, electrolysis cells

Introduction to electrolysis - electrolytes, non-electrolytes, electrode equations

You should be able to:-

(a) describe the electrode products in the electrolysis of:

(i) molten lead (II) bromide, concentrated hydrochloric acid, concentrated aqueous sodium chloride, dilute sulphuric acid (as essentially the electrolysis of water) between inert electrodes;

Electrolysis of acidified water (dilute sulfuric acid) and some sulfate salts and alkalis

Electrolysis of sodium chloride solution (brine)

Electrolysis of molten lead(II) bromide (and other molten ionic compounds)

Electrolysis of hydrochloric acid

and ...

(ii) aqueous copper (II) sulphate using carbon electrodes and using copper electrodes (as used in the refining of copper);

Electrolysis of copper(II) sulfate solution and electroplating

The purification of copper by electrolysis

(b) describe electrolysis in terms of the ions present and reactions at the electrodes in the examples given;

(c) state the general principles that metals or hydrogen are formed at the negative electrode (cathode) an that non-metals (other than hydrogen) are formed at the positive electrode (anode);

(d) predict the likely products of the electrolysis of a specified binary compound in the molten state or in concentrated aqueous solution;

(e) describe, in outline, the manufacture of: -

(i) aluminium from pure aluminium oxide in molten cryolite

The electrolysis of molten aluminium oxide - extraction of aluminium from bauxite ore

(ii) chlorine and sodium hydroxide from concentrated aqueous sodium chloride;

... Salt - sodium chloride - extraction - uses of halogens (including industrial electrolysis of brine)

(f) describe the electroplating of metals exemplified by copper plating;

Electroplating coating conducting surfaces with a metal layer

(g) state two uses of electroplating;

(h) describe the reasons for the use of copper and (steel-cored) aluminium in cables and why plastics and ceramics are used as insulators

6 ENERGY CHANGES   (Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) describe the meaning of enthalpy change in terms of exothermic (ΔH negative) and endothermic (ΔH positive) reactions;

(b) use the kilojoules, KJ, as a unit of energy;

(c) describe bond breaking as endothermic and bond forming as exothermic;

(d) state that the burning of fuels, e.g. wood, coal, oil, is exothermic;

(e) describe hydrogen as a fuel, e.g. in rockets;

(f) describe radioactive isotopes, such as 235U, as a source of nuclear energy;

(g) describe the production of electrical energy from simple cess, i.e. two electrodes in an electrolyte. This should be linked with the reactivity series;

(h) describe the use of batteries as a convenient, portable energy source;

(i) describe the use of solver salts in photography as an endothermic process involving reduction of silver ions to silver;

(j) describe photosynthesis as the reaction between carbon dioxide and water in the presence of chlorophyll and using sunlight (energy) to produce glucose

Heat changes in chemical/physical changes - exothermic and endothermic

Simple cells (batteries)

Fuel Cells e.g. the hydrogen - oxygen fuel cell

7 CHEMICAL REACTIONS   (Zimbabwe O Level Chemistry 5071)

7.1. Speed of Reaction   (how fast? how slow? why? Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) describe the effect of concentration, pressure, particle size and temperature on the speeds of reactions and explain these effects in terms of collision between reacting particles.;

(b) describe the effect of catalysts (including enzymes) on the speeds of reactions;

(c) describe how the above factors are used to explain the danger of explosive combustion with fine powders (e.g. in flour mills) and combustible gases (e.g. in mines);

(d) devise a suitable method for investigating the effect of a given variable on the speed of a reaction;

(e) interpret data obtained from experiments concerned with speed of reaction.

What do we mean by the rate/speed of reaction? how can we measure it?

Particle model of the collision theory of chemical reaction rate factors

Effect of changing reactant concentration in solution

Effect of changing pressure in reacting gases

Effect of changing particle size/surface area & stirring of a solid reactant

Effect of changing the temperature of reactants

Effect of using a catalyst in a chemical reaction

Examples of graphs of rate data, interpretation

Multiple choice Quiz on the Rates of Chemical Reactions

Crossword on Rates of Reactions * Answers

Wordfill worksheet on Rates of Chemical Reactions

(1) matching pair quizzes on Rates of Chemical Reactions and (2)

7.2. Reversible reactions   (what is a reversible reaction? Zimbabwe O Level Chemistry 5071)

You should be able to:

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

(b) state the idea that some reversible chemical reactions reach a state of dynamic equilibrium

(c) predict the effect of changing the conditions of a reversible reaction at equilibrium.

Reversible Reactions

Reversible reactions and equilibrium

7.3. Redox   (oxidation and reductions definitions, examples, Zimbabwe O Level Chemistry 5071)

Candidates should be able to:-

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

(b) define redox in terms of electron transfer and changes in oxidation state;

(c) identify redox reactions in terms of hydrogen/oxygen, and/or electron, gain/loss;

(d) describe the use of aqueous potassium iodine, acidified potassium dichromate(VI) and acidified potassium manganate(VII) in testing for oxidising and reducing agents from the colour changes produced

Introduction to oxidation and reduction and their application to REDOX reactions

8 ACIDS, BASES AND SALTS   (Zimbabwe O Level Chemistry 5071)

8.1. The characteristic properties of acids and bases   (acids, alkalis, salts, Zimbabwe O Level Chemistry 5071)

You should be able to:-

(a) describe the meaning of the terms acid and alkali in terms of the ions they contain or produce in aqueous solution and their effects on indicator paper;

(b) describe neutrality and relative acidity and alkalinity in terms of pH (whole numbers only) measured using Universal Indicator paper;

Everyday examples of acid-alkali chemistry

pH scale, indicator colours, ionic theory of acids, alkalis (bases) & neutralisation

Examples of acid, neutral or alkaline solutions

(c) describe the characteristics properties of acids as in reactions with metals, bases, alkalis, carbonates

Reactions of acids with metals/oxides/hydroxides/carbonates and neutralisation reactions

The Reactivity Series of Metals

(d) describe the characteristic properties of bases as in reactions with acids and with ammonium salts;

Reactions of bases-alkalis like sodium hydroxide

(e) describe and explain the importance of controlling the pH of soil;

Multiple choice quiz on pH, Indicators, Acids, Bases, Neutralisation and Salts

Structured question worksheet on Acid Reaction word equations and symbol equation question

Word equation answers and symbol equation answers

Word-fill worksheet on Acids, Bases, Neutralisation and Salts

Matching pair quiz on Acids, Bases, Salts and pH

8.2. Types of oxides   (link to metals and non-metals, Zimbabwe O Level Chemistry 5071)

Candidates should be able to:

Classify oxides as either acidic, basic or atmospheric relate to metallic/non-metallic character.

Periodic Table Notes - an overview, section on metals & non-metals

8.3. Preparation of salts   (methods of making salts, Zimbabwe O Level Chemistry 5071)

You should be able to:-

(a) describe the preparation, separation and purification of salts as examples of some of the techniques in Section 2.2.(b)

(Methods of preparing salts to illustrate the practical techniques should include the action of acids with metals, insoluble base and insoluble carbonates).

(b) describe the preparation of salts by titration method;

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

Making a soluble salt by neutralising a soluble acid with a soluble base (alkali)

Making a soluble salt by from an acid with a metal or insoluble base – oxide, hydroxide or carbonate

Preparing an insoluble salt by mixing solutions of two soluble compounds

8.4. Identification of ions and gases   (tests for gases and ions, Zimbabwe O Level Chemistry 5071)

Candidates should be able to:

describe and explain the use of the following tests to identify:

(i) aqueous cations; aluminium, ammonium, calcium, copper (ii), iron (ii), iron (iii) and zinc using aqueous sodium hydroxide and aqueous ammonia, as appropriate (formulae of complex ions are not required);

(ii) anions; carbonate (by reaction with dilute acid and then limewater); chloride (by reaction, under acidic conditions, with aqueous silver nitrate); iodide (by reaction, under acidic conditions, with aqueous lead (ii) nitrate); nitrate (by reduction with aluminium to ammonia) and sulphate (by reaction, under acidic conditions, with aqueous barium ions);

(iii) gases; ammonia (using damp red litmus paper); carbon dioxide (using limewater); chloride (using damp litmus paper); hydrogen (using lighted splint); oxygen (using glowing splint) and sulphur dioxide (using acidified potassium dichromate (IV)).

Quick summary of tests for gases and ions including equations

chemical tests for cations and chemical tests for anions (more detailed notes, use alphabetical index)

and TESTS for gases, water and non–metallic elements (more detailed notes, use alphabetical index)

9 THE PERIODIC TABLE   (survey of elements of the periodic table, Zimbabwe O Level Chemistry 5071)

You should be able to describe the Periodic Table as a method of classifying elements and its use to predict properties of elements.

Periodic Table Notes - an overview, groups, periods, metals & non-metals

Multiple choice quiz on the basics of the Periodic Table

Task sheet worksheet on Periodic Table history * (answers)

Basic Periodic Table Task sheet worksheet * (answers)

Gap-fill worksheet on the Periodic Table

Element Symbol-name QUIZ easier-pictorial  or  harder-no pictures!

Giant Periodic Table crossword puzzle

9.1. Periodic Trends  (trends in the periodic table, periods, groups, Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) describe the changes from metallic to non-metallic character across a period;

(b) describe the relationship between Group number, number of valency electrons and metallic/non-metallic character;

Periodic Table Notes - an overview, groups, periods, metals & non-metals

Matching pair quiz on Atomic and electronic structure and the Periodic Table

9.2. Group properties   (physical and chemical properties of alkali metals, halogens, Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) describe lithium, sodium and potassium in Group 1 (the alkali metals) as a collection of relative soft, low density metals showing a trend in melting points and in reaction with water

(b) predict the properties of elements in Group 1, given data, where appropriate;
 

Group 1 Alkali Metals - physical and chemical properties

Multiple choice quiz on the Group 1 Alkali Metals

Word-fill worksheet on the Group 1 Alkali Metals

(c) 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 other halide ions;

(d) predict the properties of elements in Group VII, given data, where appropriate;

(e) identify trends in other Groups given information about the elements concerned;

Group 7 Halogens - physical and chemical properties

Multiple choice quiz on the Group 7 Halogens

A Group 7 "Halogens" task sheet worksheet * (answers)

Word-fill work sheet on the Halogens

The Halogens (matching pair quiz on their appearance)

9.3. Noble gases   (properties of noble gases, Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) describe the noble gases as being uncreative;

(b) describe the uses of the noble gases in providing an inert atmosphere, e.g. argon in lamps; helium for filling balloons

Group 0 Noble Gases

Multiple choice quiz on Group 0 The Noble Gases

Wordfill worksheet on the Noble Gases (answers)

10 METALS   (Zimbabwe O Level Chemistry 5071)

10.1. Properties of metals   (characteristic metallic properties, Zimbabwe O Level Chemistry 5071)

Periodic Table Notes - section on typical properties of metals & non-metals

Metallic bonding, properties and uses of metals

10.2. Reactivity series   (reactivity of metals with water, acids, salt solutions, Zimbabwe O Level Chemistry 5071)

You should be able to:-

(a) place calcium, copper, (hydrogen), iron, magnesium, potassium, silver, sodium and zinc in order to reactivity by reference to:

(i) the reactions, if any, of the metals with water or steam, dilute hydrochloric acid;

(ii) the reduction, if any, of their oxides with carbon and with oxygen;

(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) describe the action of heat on the carbonates of the listed metals

(d) account of the apparent unreactivity of aluminium in terms of the presence of an oxide layer which adheres to the metal;

(e) deduce an order or reactivity from a given set of experimental results.

The Reactivity Series of Metals

Metal Reactivity Series Experiments-Observations

The corrosion of metals and the prevention of iron rusting

Limestone: Section on the thermal decompositions of carbonates

10.3. Extraction and uses of metals   (how do we extract metals from their ores?, Zimbabwe O Level Chemistry 5071)

You should be able to:

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

Introduction to Metal Extraction

(b) describe the essential reactions in the extraction of iron from haematite in the blast furnace;

(c) describe the ideas of changing the properties of iron by the controlled use of additives to form alloys called steels;

Extraction of Iron and Steel Making

(d) state the use of mild steel (car bodies and machinery) and stainless steel (chemical plant and cutlery)

(e) describe, in outline, the extraction of aluminium from pure aluminium oxide;

Extraction of Aluminium

(f) state the uses of aluminium: in the manufacture of aircraft because of it strength and low density;

How can metals be made more useful? (alloys of Al, Fe, steel etc.)

(g) state the uses of zinc for galvanising and for making brass (with copper);

(h) state the uses of copper related to its properties, e.g. electrical wiring.

Transition Metals eg uses of iron and copper plus mention of aluminium

11 NON-METALS   (Zimbabwe O Level Chemistry 5071)

11.1. Hydrogen   (chemistry and uses of hydrogen, Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) describe the formation of hydrogen as a product of the reaction between:-

(i) reactive metals and water

(ii) metals and acids

The Reactivity Series of Metals

Reactions of acids with metals

Metal Reactivity Series Experiments-Observations

(b) describe the formation of hydrogen as a product of electrolysis of certain aqueous solutions related to the ions present and their position in the reactivity series;

Electrolysis of acidified water (dilute sulfuric acid) and some sulfate salts and alkalis

(c) describe, in outline, the manufacture of hydrogen from the reaction between methane and steam;

The Haber Synthesis of ammonia - including manufacture and use of hydrogen

(d) state the uses of hydrogen in the manufacture of ammonia, and of margarine from unsaturated vegetable oils, and as a fuel in rockets;

(e) describe, in outline, he purification of the water supply in terms of filtration and chlorination;

Water cycle, potable water, water treatment, pollution, tests for ions in water

(f) state some of the uses of water in industry and in the home;

(g) describe a chemical test for water - turns white anhydrous copper sulfate blue

11.2. Oxygen   (air pollution, preventing rusting, Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) describe, in simple terms, the ideas of respiration, combustion and rusting;

Types of chemical reactions and QUIZ on types of chemical reaction

(b) describe the volume composition of clean air in terms of 79% nitrogen, 20% oxygen, with the remainder being noble gases (with argon as the main constituent), carbon dioxide and variable amounts of water vapour;

(c) name common pollutants of air (carbon monoxide, sulphur dioxide, oxides of nitrogen, e.g. NO₂, and led compounds);

Our atmosphere - composition, determining % oxygen, uses of gases in air

(d) state the source of each of these pollutants:

(i) carbon monoxide from the incomplete combustion of carbon – containing substances;

(ii) sulphur dioxide from the combustion of fossil fuels which contain sulphur compounds (leading to ‘acid rain’);

(iii) oxides of nitrogen and lead compounds from car exhausts

(e) state the adverse effect of acidic pollutants on buildings and plants, and of carbon monoxide;

Air pollution - sulfur oxides, nitrogen oxides, acid rain

Air pollution - incomplete combustion, carbon monoxide & soot

(f) describe the separation of oxygen and nitrogen from liquid air by fractional distillation;

(g) name the uses of oxygen in making steel, oxygen tents in hospitals, and with acetylene ( hydrocarbon) in welding;

(h) describe paint and other coatings, including galvanising, as methods of rust prevention;

(i) describe sacrificial protection in terms of the reactivity series of metals.

The corrosion of metals and the prevention of iron rusting

11.3. Nitrogen   (Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) state the use of nitrogen in the manufacture of ammonia;

(b) describe the essential conditions for the manufacture of ammonia by the Haber process;

(c) describe the displacement of ammonia from its salts;

(d) state the need for nitrogen, phosphorus and potassium compounds in plant life;

(e) name the uses of ammonia in the manufacture of fertilisers such as ammonium sulphate and nitrate;

The Haber Synthesis of ammonia - nitrogen fixation

Manufacture and uses of fertilisers, preparation of ammonium salts, NPK fertilisers-environmental problems

11.4. Sulphur   (reactions, uses and manufacture of sulfuric acid, Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) state the uses of sulphur dioxide as a bleach in the manufacture of wood pulp for papers; as a food preservative (by killing bacteria);

(b) describe the manufacture of sulphuric acid as a typical acid from sulphur by the Contact process;

(c) describe the properties of dilute sulphuric acid;

(d) state the uses of sulphuric acid as in the manufacture of detergents and fertilisers.

Reactions of acids with metals/oxides/hydroxides/carbonates and neutralisation reactions

Contact Process for manufacturing sulfuric acid, the importance of sulphuric acid

11.5. Chlorine   (uses of salt - sodium chloride, Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) name some sources of sodium chloride;

(b) describe the importance of sodium chloride as a source for chlorine and sodium hydroxide;

(c) state the main uses of chlorine in sterilising water; manufacturing plastics, e.g. pvc; making domestic bleaches

Salt - sodium chloride - extraction - uses of halogens (including industrial electrolysis of brine)

11.6. Silicon   (silica, Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) describe silicon as a common element in most rocks (being combined with oxygen);

(i) as silicon (IV) oxide (silicon dioxide), e.g. quartz

(ii) as complex silicates, e.g. mica

(b) describe sand as impure form of silicon (IV) oxide;

(c) state the use of sand in making glass (a mixture of silicates) and as a source of silicon (by reduction);

(d) state the uses of silicon in semiconductors (for electronics) and for making silicones

(e) state that different silicones are able to exist as oils, waxes or plastics

(f) explain the fire resistance o a silicone plastic to the nature of the combustion product and compare this to carbon-based polymers;

Covalent bonding and giant structures - silica

11.7. Carbon and carbonates   (structure and uses of diamond, graphite, Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) name the allotropes of carbon as graphite and diamond

(b) state use of relate their structures to the uses of graphite e.g. as a lubricant and diamond in cutting

(c) describe the manufacture of lime (calcium oxide) from calcium carbonate (limestone) in terms of the chemical reaction involved

(d) state some uses of lime and slaked lime as in treating acidic soil and neutralizing acidic industrial waste products

(e) state the uses of calcium carbonate in the manufacture of iron, glass and of cement

Covalent bonding and giant structures and their properties and uses - diamond and graphite

Notes on limestone, lime and uses, glass etc.

12 ORGANIC CHEMISTRY   (organic chemistry for Zimbabwe O Level Chemistry 5071)

12.1. Name of compounds   (naming and structure of organic compounds, Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) name, and draw the structure of, the unbranched alkanes, alkenes (not cis-trans), alcohols and acids containing up to four carbon atoms per molecule and the products of the reactions stated in Sections 12.4 to 12.6

(b) state the type of compound present, given a chemical name ending in –ane, -ene, -ol, -oic acid, or given a molecular structure

Introduction to Organic Chemistry - homologous series - functional groups

Alkanes - saturated hydrocarbons, structure and names

Alkenes - unsaturated hydrocarbons - structure and names

Alcohols - structures and names

Carboxylic acids - structure and names

12.2. Fuels   (fossil fuels from crude oil and natural gas, Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) name natural gas and petroleum as sources of fuels;

(b) name methane as the main constituent of natural gas;

(c) describe petroleum as a mixture of hydrocarbons and its separation into useful fraction b fractional distillation;

(d) name the uses of the fractions: petrol (gasoline) fraction for fuel in cars; paraffin (kerosene) fraction for oil stoves and aircraft fuel for fuel in diesel engines: lubricating fraction for lubricants and making waxes and polishes: bitumen for making roads.

Fossil Fuels

Fractional distillation of crude oil & molecular properties and uses of fractions

12.3. Homologous series   (organic chemistry - homologous series, Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) describe the general characteristics of a homologous series

(b) describe and identify (given molecular structures) isomerism

Introduction to Organic Chemistry - homologous series - functional groups

Isomerism in organic chemistry (advanced page, but see O level pages for alkanes, alkenes, alcohols and carboxylic acids)

12.4. Alkanes   (chemistry of alkanes, Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) describe the properties of alkanes (exemplified by methane) as being generally unreactive expect in terms of burning and substitution by chlorine;

(b) draw the structures of branched and unbranched alkanes containing four or five carbon atoms per molecule.

Alkanes - saturated hydrocarbons, structure and reactions including combustion

12.5. Alkenes   (chemistry of alkenes, Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) describe the manufacture of alkenes and of hydrogen by cracking;

(b) describe the properties of alkenes in terms of burning; polymerisation; addition reactions with bromine, steam and hydrogen (margarine manufacture, considered as the addition of hydrogen to unsaturated vegetable oils in order to give a solid product);

(c) distinguish between saturated and unsaturated hydrocarbons from molecular structures; by using aqueous bromine;

(d) describe the formation of poly(ethene) as an example of addition polymerisation of monomer units;

(e) name some uses of poly(ethene) as a typical plastic, e.g. plastic bags.

Alkenes - unsaturated hydrocarbons - structure and reactions

Addition polymers, plastics, uses and problems including poly(ethene)

12.6. Alcohol   (properties and chemistry of alcohols, Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) describe the formation of ethanol by fermentation and by the catalytic addition of steam to ethane;

(b) describe the properties of ethanol in terms of burning and of oxidation;

(c) name the uses of ethanol as a solvent; as a fuel.

Alcohols - structures including ethanol - manufacture, properties and reactions

BIOFUELS

12.7. Acids   (chemistry of carboxylic acids, Zimbabwe O Level Chemistry 5071)

You should be able to:

(a) describe the formation of ethanoic acid by the oxidation of ethanol by

(i) the action of atmospheric oxygen

(ii) acidified potassium dichromate (VI)

(b) describe ethanoic acid as an acid

(c) describe the reaction of ethanoic acid ethanol to give an ester (ethyl ethanoate)

Carboxylic acids and esters, structure and reactions

12.8. Macromolecules   (Zimbabwe O Level Chemistry 5071)

You should be able to describe macromolecules in terms of large molecules built up form small units, different macromolecules having different units and/or different linkages.

12.8. (a) Synthetic Polymers   (Zimbabwe O Level Chemistry 5071)

You should be able to:

(i) deduce the structure of the polymer product from a given alkene and vice versa

(ii) describe the formation of nylon (a polyamide) and Terylene (a polyester) by condensation polymerization, know the simplified representations of the structure of nylon and Terylene

(details of manufacture and mechanism of these polymerization are not required)

(iii) name some typical uses of man-made fibres such as nylon and Terylene, e.g. clothing

(iv) describe the pollution problems caused by non-biodegradable plastics

Addition polymers, plastics, uses and problems, environmental problems, including poly(ethene)

Comparing addition polymers and condensation polymers, thermosets, fibres, thermosoftening etc.

12.8. (b) Natural macromolecules   (carbohydrates, proteins, fats, Zimbabwe O Level Chemistry 5071)

You should be able to:

(i) name proteins, fats and carbohydrates as the main constituents of food

(ii) describe proteins as possessing the same (amide) linkages as nylon but with different units

(iii) describe the hydrolysis of protein to amino acids (structures and names not required)

(iv) describe fats (and vegetable oils) as esters possessing the same linkages as Terylene but with different structures

(v) describe soap as a product of hydrolysis of fat

(vi) describe the carbohydrate starch as a macromolecule represented as being formed by the condensation polymerization of smaller carbohydrate units called sugars - know the simplified representation of starch molecules

(vii) describe the acid hydrolysis of carbohydrates such as starch to given simple sugars

(viii) describe the fermentation of simple sugars to produce ethanol (and carbon dioxide) (Candidates will not be expected to give the molecular formulae of sugars)

(ix) describe, in outline, the uses of chromatography in separating and identifying the products of hydrolysis of carbohydrates and proteins

Natural Molecules - carbohydrates - sugars - starch

Amino acids, proteins, enzymes & chromatography

Oils, fats, margarine and soaps