IGCSE Chemistry 0620 Syllabus PDF

Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. 3 Subject content This syllabus gives you the flexibility to design a course that will interest, challenge and engage your learners. Where appropriate you are responsible for selecting resources and exam...

Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. 3 Subject content This syllabus gives you the flexibility to design a course that will interest, challenge and engage your learners. Where appropriate you are responsible for selecting resources and examples to support your learners’ study. These should be appropriate for the learners’ age, cultural background and learning context as well as complying with your school policies and local legal requirements. All candidates should be taught the Core subject content. Candidates who are only taught the Core subject content can achieve a maximum of grade C. Candidates aiming for grades A* to C should be taught the Extended subject content. The Extended subject content includes both the Core and the Supplement. Scientific subjects are, by their nature, experimental. Learners should pursue a fully integrated course which allows them to develop their experimental skills by doing practical work and investigations. Practical work helps students to: use equipment and materials accurately and safely develop observational and problem-solving skills develop a deeper understanding of the syllabus topics and the scientific approach appreciate how scientific theories are developed and tested transfer the experimental skills acquired to unfamiliar contexts develop positive scientific attitudes such as objectivity, integrity, cooperation, enquiry and inventiveness develop an interest and enjoyment in science. 1 States of matter 1.1 Solids, liquids and gases Core Supplement 1 State the distinguishing properties of solids, liquids and gases 2 Describe the structures of solids, liquids and gases in terms of particle separation, arrangement and motion 3 Describe changes of state in terms of melting, 5 Explain changes of state in terms of kinetic boiling, evaporating, freezing and condensing particle theory, including the interpretation of heating and cooling curves 4 Describe the effects of temperature and pressure 6 Explain, in terms of kinetic particle theory, the on the volume of a gas effects of temperature and pressure on the volume of a gas 1.2 Diffusion Core Supplement 1 Describe and explain diffusion in terms of kinetic 2 Describe and explain the effect of relative particle theory molecular mass on the rate of diffusion of gases 10 www.cambridgeinternational.org/igcse Back to contents page  Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 2 Atoms, elements and compounds 2.1 Elements, compounds and mixtures Core Supplement 1 Describe the differences between elements, compounds and mixtures 2.2 Atomic structure and the Periodic Table Core Supplement 1 Describe the structure of the atom as a central nucleus containing neutrons and protons surrounded by electrons in shells 2 State the relative charges and relative masses of a proton, a neutron and an electron 3 Define proton number / atomic number as the number of protons in the nucleus of an atom 4 Define mass number / nucleon number as the total number of protons and neutrons in the nucleus of an atom 5 Determine the electronic configuration of elements and their ions with proton number 1 to 20, e.g. 2,8,3 6 State that: (a) Group VIII noble gases have a full outer shell (b) the number of outer shell electrons is equal to the group number in Groups I to VII (c) the number of occupied electron shells is equal to the period number 2.3 Isotopes Core Supplement 1 Define isotopes as different atoms of the same 3 State that isotopes of the same element have element that have the same number of protons the same chemical properties because they have but different numbers of neutrons the same number of electrons and therefore the 2 Interpret and use symbols for atoms, e.g. 126C, and same electronic configuration ions, e.g. 35 17 Cl – 4 Calculate the relative atomic mass of an element from the relative masses and abundances of its isotopes Back to contents page www.cambridgeinternational.org/igcse 11 Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 2.4 Ions and ionic bonds Core Supplement 1 Describe the formation of positive ions, known as 5 Describe the giant lattice structure of ionic cations, and negative ions, known as anions compounds as a regular arrangement of 2 State that an ionic bond is a strong electrostatic alternating positive and negative ions attraction between oppositely charged ions 3 Describe the formation of ionic bonds between 6 Describe the formation of ionic bonds between elements from Group I and Group VII, including ions of metallic and non-metallic elements, the use of dot-and-cross diagrams including the use of dot-and-cross diagrams 4 Describe the properties of ionic compounds: 7 Explain in terms of structure and bonding the (a) high melting points and boiling points properties of ionic compounds: (b) good electrical conductivity when aqueous or (a) high melting points and boiling points molten and poor when solid (b) good electrical conductivity when aqueous or molten and poor when solid 2.5 Simple molecules and covalent bonds Core Supplement 1 State that a covalent bond is formed when a pair of electrons is shared between two atoms leading to noble gas electronic configurations 2 Describe the formation of covalent bonds in 4 Describe the formation of covalent bonds in simple molecules, including H2, Cl 2, H2O, CH4, simple molecules, including CH3OH, C2H4, O2, NH3 and HCl. Use dot-and-cross diagrams to CO2 and N2. Use dot-and-cross diagrams to show show the electronic configurations in these and the electronic configurations in these and similar similar molecules molecules 3 Describe in terms of structure and bonding the 5 Explain in terms of structure and bonding the properties of simple molecular compounds: properties of simple molecular compounds: (a) low melting points and boiling points (a) low melting points and boiling points in (b) poor electrical conductivity terms of weak intermolecular forces (specific types of intermolecular forces are not required) (b) poor electrical conductivity 2.6 Giant covalent structures Core Supplement 1 Describe the giant covalent structures of graphite 3 Describe the giant covalent structure of and diamond silicon(IV) oxide, SiO2 2 Relate the structures and bonding of graphite and 4 Describe the similarity in properties between diamond to their uses, limited to: diamond and silicon(IV) oxide, related to their (a) graphite as a lubricant and as an electrode structures (b) diamond in cutting tools 12 www.cambridgeinternational.org/igcse Back to contents page  Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 2.7 Metallic bonding Core Supplement 1 Describe metallic bonding as the electrostatic attraction between the positive ions in a giant metallic lattice and a ‘sea’ of delocalised electrons 2 Explain in terms of structure and bonding the properties of metals: (a) good electrical conductivity (b) malleability and ductility 3 Stoichiometry 3.1 Formulae Core Supplement 1 State the formulae of the elements and compounds named in the subject content 2 Define the molecular formula of a compound as 5 Define the empirical formula of a compound as the number and type of different atoms in one the simplest whole number ratio of the different molecule atoms or ions in a compound 3 Deduce the formula of a simple compound from 6 Deduce the formula of an ionic compound from the relative numbers of atoms present in a model the relative numbers of the ions present in a or a diagrammatic representation model or a diagrammatic representation or from the charges on the ions 4 Construct word equations and symbol equations 7 Construct symbol equations with state symbols, to show how reactants form products, including including ionic equations state symbols 8 Deduce the symbol equation with state symbols for a chemical reaction, given relevant information 3.2 Relative masses of atoms and molecules Core Supplement 1 Describe relative atomic mass, Ar, as the average mass of the isotopes of an element compared to 1/12th of the mass of an atom of 12C 2 Define relative molecular mass, Mr, as the sum of the relative atomic masses. Relative formula mass, Mr, will be used for ionic compounds 3 Calculate reacting masses in simple proportions. Calculations will not involve the mole concept Back to contents page www.cambridgeinternational.org/igcse 13 Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 3.3 The mole and the Avogadro constant Core Supplement 2 State that the mole, mol, is the unit of amount of substance and that one mole contains 6.02 × 1023 particles, e.g. atoms, ions, molecules; this number is the Avogadro constant 3 Use the relationship mass (g) amount of substance (mol) = molar mass (g / mol) to calculate: (a) amount of substance (b) mass (c) molar mass (d) relative atomic mass or relative molecular / formula mass (e) number of particles, using the value of the Avogadro constant 4 Use the molar gas volume, taken as 24 dm3 at room temperature and pressure, r.t.p., in calculations involving gases 1 State that concentration can be measured in 5 Calculate stoichiometric reacting masses, limiting g / dm3 or mol / dm3 reactants, volumes of gases at r.t.p., volumes of solutions and concentrations of solutions expressed in g / dm3 and mol / dm3, including conversion between cm3 and dm3 6 Use experimental data from a titration to calculate the moles of solute, or the concentration or volume of a solution 7 Calculate empirical formulae and molecular formulae, given appropriate data 8 Calculate percentage yield, percentage composition by mass and percentage purity, given appropriate data 4 Electrochemistry 4.1 Electrolysis Core Supplement 1 Define electrolysis as the decomposition of an 8 Describe the transfer of charge during electrolysis ionic compound, when molten or in aqueous to include: solution, by the passage of an electric current (a) the movement of electrons in the external 2 Identify in simple electrolytic cells: circuit (a) the anode as the positive electrode (b) the loss or gain of electrons at the electrodes (b) the cathode as the negative electrode (c) the movement of ions in the electrolyte (c) the electrolyte as the molten or aqueous substance that undergoes electrolysis 14 www.cambridgeinternational.org/igcse Back to contents page  Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 4.1 Electrolysis continued Core Supplement 3 Identify the products formed at the electrodes 9 Identify the products formed at the electrodes and describe the observations made during the and describe the observations made during the electrolysis of: electrolysis of aqueous copper(II) sulfate using (a) molten lead(II) bromide inert carbon / graphite electrodes and when using copper electrodes (b) concentrated aqueous sodium chloride (c) dilute sulfuric acid using inert electrodes made of platinum or carbon / graphite 4 State that metals or hydrogen are formed at the cathode and that non-metals (other than hydrogen) are formed at the anode 5 Predict the identity of the products at each 10 Predict the identity of the products at each electrode for the electrolysis of a binary electrode for the electrolysis of a halide compound in the molten state compound in dilute or concentrated aqueous solution 11 Construct ionic half-equations for reactions at the anode (to show oxidation) and at the cathode (to show reduction) 6 State that metal objects are electroplated to improve their appearance and resistance to corrosion 7 Describe how metals are electroplated 4.2 Hydrogen–oxygen fuel cells Core Supplement 1 State that a hydrogen–oxygen fuel cell uses 2 Describe the advantages and disadvantages of hydrogen and oxygen to produce electricity with using hydrogen–oxygen fuel cells in comparison water as the only chemical product with gasoline / petrol engines in vehicles Back to contents page www.cambridgeinternational.org/igcse 15 Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 5 Chemical energetics 5.1 Exothermic and endothermic reactions Core Supplement 1 State that an exothermic reaction transfers 4 State that the transfer of thermal energy during a thermal energy to the surroundings leading to an reaction is called the enthalpy change, ∆H, of the increase in the temperature of the surroundings reaction. ∆H is negative for exothermic reactions 2 State that an endothermic reaction takes in and positive for endothermic reactions thermal energy from the surroundings leading to a decrease in the temperature of the surroundings 5 Define activation energy, Ea, as the minimum energy that colliding particles must have to react 3 Interpret reaction pathway diagrams showing 6 Draw and label reaction pathway diagrams for exothermic and endothermic reactions exothermic and endothermic reactions using information provided, to include: (a) reactants (b) products (c) enthalpy change of the reaction, ∆H (d) activation energy, Ea 7 State that bond breaking is an endothermic process and bond making is an exothermic process and explain the enthalpy change of a reaction in terms of bond breaking and bond making 8 Calculate the enthalpy change of a reaction using bond energies 16 www.cambridgeinternational.org/igcse Back to contents page  Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 6 Chemical reactions 6.1 Physical and chemical changes Core Supplement 1 Identify physical and chemical changes, and describe the differences between them 6.2 Rate of reaction Core Supplement 5 Describe collision theory in terms of: (a) number of particles per unit volume (b) frequency of collisions between particles (c) kinetic energy of particles (d) activation energy, Ea 1 Describe the effect on the rate of reaction of: 6 Describe and explain the effect on the rate of (a) changing the concentration of solutions reaction of: (b) changing the pressure of gases (a) changing the concentration of solutions (c) changing the surface area of solids (b) changing the pressure of gases (d) changing the temperature (c) changing the surface area of solids (e) adding or removing a catalyst, including (d) changing the temperature enzymes (e) adding or removing a catalyst, including enzymes using collision theory 2 State that a catalyst increases the rate of a 7 State that a catalyst decreases the activation reaction and is unchanged at the end of a energy, Ea, of a reaction reaction 3 Describe practical methods for investigating the 8 Evaluate practical methods for investigating the rate of a reaction including change in mass of a rate of a reaction including change in mass of a reactant or a product and the formation of a gas reactant or a product and the formation of a gas 4 Interpret data, including graphs, from rate of reaction experiments Back to contents page www.cambridgeinternational.org/igcse 17 Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 6.3 Reversible reactions and equilibrium Core Supplement 1 State that some chemical reactions are reversible 3 State that a reversible reaction in a closed system as shown by the symbol ⇌ is at equilibrium when: (a) the rate of the forward reaction is equal to the rate of the reverse reaction (b) the concentrations of reactants and products are no longer changing 2 Describe how changing the conditions can 4 Predict and explain, for a reversible reaction, how change the direction of a reversible reaction for: the position of equilibrium is affected by: (a) the effect of heat on hydrated compounds (a) changing temperature (b) the addition of water to anhydrous (b) changing pressure compounds (c) changing concentration limited to copper(II) sulfate and (d) using a catalyst cobalt(II) chloride using information provided 5 State the symbol equation for the production of ammonia in the Haber process, N2(g) + 3H2(g) ⇌ 2NH3(g) 6 State the sources of the hydrogen (methane) and nitrogen (air) in the Haber process 7 State the typical conditions in the Haber process as 450 °C, 20 000 kPa / 200 atm and an iron catalyst 8 State the symbol equation for the conversion of sulfur dioxide to sulfur trioxide in the Contact process, 2SO2(g) + O2(g) ⇌ 2SO3(g) 9 State the sources of the sulfur dioxide (burning sulfur or roasting sulfide ores) and oxygen (air) in the Contact process 10 State the typical conditions for the conversion of sulfur dioxide to sulfur trioxide in the Contact process as 450 °C, 200 kPa / 2 atm and a vanadium(V) oxide catalyst 11 Explain, in terms of rate of reaction and position of equilibrium, why the typical conditions stated are used in the Haber process and in the Contact process, including safety considerations and economics 18 www.cambridgeinternational.org/igcse Back to contents page  Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 6.4 Redox Core Supplement 1 Use a Roman numeral to indicate the oxidation number of an element in a compound 2 Define redox reactions as involving simultaneous oxidation and reduction 3 Define oxidation as gain of oxygen and reduction 6 Define oxidation in terms of: as loss of oxygen (a) loss of electrons (b) an increase in oxidation number 7 Define reduction in terms of: (a) gain of electrons (b) a decrease in oxidation number 4 Identify redox reactions as reactions involving 8 Identify redox reactions as reactions involving gain and loss of oxygen gain and loss of electrons 5 Identify oxidation and reduction in redox 9 Identify redox reactions by changes in oxidation reactions number using: (a) the oxidation number of elements in their uncombined state is zero (b) the oxidation number of a monatomic ion is the same as the charge on the ion (c) the sum of the oxidation numbers in a compound is zero (d) the sum of the oxidation numbers in an ion is equal to the charge on the ion 10 Identify redox reactions by the colour changes involved when using acidified aqueous potassium manganate(VII) or aqueous potassium iodide 11 Define an oxidising agent as a substance that oxidises another substance and is itself reduced 12 Define a reducing agent as a substance that reduces another substance and is itself oxidised 13 Identify oxidising agents and reducing agents in redox reactions Back to contents page www.cambridgeinternational.org/igcse 19 Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 7 Acids, bases and salts 7.1 The characteristic properties of acids and bases Core Supplement 1 Describe the characteristic properties of acids in terms of their reactions with: (a) metals (b) bases (c) carbonates 2 Describe acids in terms of their effect on: (a) litmus (b) thymolphthalein (c) methyl orange 3 State that bases are oxides or hydroxides of metals and that alkalis are soluble bases 4 Describe the characteristic properties of bases in terms of their reactions with: (a) acids (b) ammonium salts 5 Describe alkalis in terms of their effect on: (a) litmus (b) thymolphthalein (c) methyl orange 6 State that aqueous solutions of acids contain H+ 9 Define acids as proton donors and bases as ions and aqueous solutions of alkalis contain OH– proton acceptors ions 10 Define a strong acid as an acid that is completely dissociated in aqueous solution and a weak acid as an acid that is partially dissociated in aqueous solution 11 State that hydrochloric acid is a strong acid, as shown by the symbol equation, HCl (aq) → H+(aq) + Cl –(aq) 12 State that ethanoic acid is a weak acid, as shown by the symbol equation, CH3COOH(aq) ⇌ H+(aq) + CH3COO–(aq) 7 Describe how to compare hydrogen ion concentration, neutrality, relative acidity and relative alkalinity in terms of colour and pH using universal indicator paper 8 Describe the neutralisation reaction between an acid and an alkali to produce water, H+ (aq) + OH– (aq) → H2O (l ) 20 www.cambridgeinternational.org/igcse Back to contents page  Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 7.2 Oxides Core Supplement 1 Classify oxides as acidic, including SO2 and CO2, 2 Describe amphoteric oxides as oxides that react or basic, including CuO and CaO, related to with acids and with bases to produce a salt and metallic and non-metallic character water 3 Classify Al 2O3 and ZnO as amphoteric oxides 7.3 Preparation of salts Core Supplement 1 Describe the preparation, separation and 4 Describe the preparation of insoluble salts by purification of soluble salts by reaction of an acid precipitation with: (a) an alkali by titration (b) excess metal (c) excess insoluble base (d) excess insoluble carbonate 2 Describe the general solubility rules for salts: (a) sodium, potassium and ammonium salts are soluble (b) nitrates are soluble (c) chlorides are soluble, except lead and silver (d) sulfates are soluble, except barium, calcium and lead (e) carbonates are insoluble, except sodium, potassium and ammonium (f) hydroxides are insoluble, except sodium, potassium, ammonium and calcium (partially) 3 Define a hydrated substance as a substance 5 Define the term water of crystallisation as the that is chemically combined with water and an water molecules present in hydrated crystals, anhydrous substance as a substance containing including CuSO4 5H2O and CoCl 2 6H2O no water Back to contents page www.cambridgeinternational.org/igcse 21 Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 8 The Periodic Table 8.1 Arrangement of elements Core Supplement 1 Describe the Periodic Table as an arrangement of elements in periods and groups and in order of increasing proton number / atomic number 2 Describe the change from metallic to non-metallic character across a period 3 Describe the relationship between group number and the charge of the ions formed from elements in that group 4 Explain similarities in the chemical properties of elements in the same group of the Periodic Table in terms of their electronic configuration 5 Explain how the position of an element in 6 Identify trends in groups, given information the Periodic Table can be used to predict its about the elements properties 8.2 Group I properties Core Supplement 1 Describe the Group I alkali metals, lithium, sodium and potassium, as relatively soft metals with general trends down the group, limited to: (a) decreasing melting point (b) increasing density (c) increasing reactivity 2 Predict the properties of other elements in Group I, given information about the elements 8.3 Group VII properties Core Supplement 1 Describe the Group VII halogens, chlorine, bromine and iodine, as diatomic non-metals with general trends down the group, limited to: (a) increasing density (b) decreasing reactivity 2 State the appearance of the halogens at r.t.p. as: (a) chlorine, a pale yellow-green gas (b) bromine, a red-brown liquid (c) iodine, a grey-black solid 3 Describe and explain the displacement reactions of halogens with other halide ions 4 Predict the properties of other elements in Group VII, given information about the elements 22 www.cambridgeinternational.org/igcse Back to contents page  Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 8.4 Transition elements Core Supplement 1 Describe the transition elements as metals that: 2 Describe transition elements as having ions with (a) have high densities variable oxidation numbers, including iron(II) and iron(III) (b) have high melting points (c) form coloured compounds (d) often act as catalysts as elements and in compounds 8.5 Noble gases Core Supplement 1 Describe the Group VIII noble gases as unreactive, monatomic gases and explain this in terms of electronic configuration 9 Metals 9.1 Properties of metals Core Supplement 1 Compare the general physical properties of metals and non-metals, including: (a) thermal conductivity (b) electrical conductivity (c) malleability and ductility (d) melting points and boiling points 2 Describe the general chemical properties of metals, limited to their reactions with: (a) dilute acids (b) cold water and steam (c) oxygen Back to contents page www.cambridgeinternational.org/igcse 23 Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 9.2 Uses of metals Core Supplement 1 Describe the uses of metals in terms of their physical properties, including: (a) aluminium in the manufacture of aircraft because of its low density (b) aluminium in the manufacture of overhead electrical cables because of its low density and good electrical conductivity (c) aluminium in food containers because of its resistance to corrosion (d) copper in electrical wiring because of its good electrical conductivity and ductility 9.3 Alloys and their properties Core Supplement 1 Describe an alloy as a mixture of a metal with other elements, including: (a) brass as a mixture of copper and zinc (b) stainless steel as a mixture of iron and other elements such as chromium, nickel and carbon 2 State that alloys can be harder and stronger than 5 Explain in terms of structure how alloys can the pure metals and are more useful be harder and stronger than the pure metals because the different sized atoms in alloys mean the layers can no longer slide over each other 3 Describe the uses of alloys in terms of their physical properties, including stainless steel in cutlery because of its hardness and resistance to rusting 4 Identify representations of alloys from diagrams of structure 24 www.cambridgeinternational.org/igcse Back to contents page  Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 9.4 Reactivity series Core Supplement 1 State the order of the reactivity series as: 4 Describe the relative reactivities of metals in potassium, sodium, calcium, magnesium, terms of their tendency to form positive ions, by aluminium, carbon, zinc, iron, hydrogen, copper, displacement reactions, if any, with the aqueous silver, gold ions of magnesium, zinc, iron, copper and silver 2 Describe the reactions, if any, of: (a) potassium, sodium and calcium with cold water (b) magnesium with steam (c) magnesium, zinc, iron, copper, silver and gold with dilute hydrochloric acid and explain these reactions in terms of the position of the metals in the reactivity series 5 Explain the apparent unreactivity of aluminium in terms of its oxide layer 3 Deduce an order of reactivity from a given set of experimental results 9.5 Corrosion of metals Core Supplement 1 State the conditions required for the rusting of iron and steel to form hydrated iron(III) oxide 2 State some common barrier methods, including 4 Describe the use of zinc in galvanising as an painting, greasing and coating with plastic example of a barrier method and sacrificial 3 Describe how barrier methods prevent rusting by protection excluding oxygen or water 5 Explain sacrificial protection in terms of the reactivity series and in terms of electron loss Back to contents page www.cambridgeinternational.org/igcse 25 Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 9.6 Extraction of metals Core Supplement 1 Describe the ease in obtaining metals from their ores, related to the position of the metal in the reactivity series 2 Describe the extraction of iron from hematite in 4 State the symbol equations for the extraction of the blast furnace, limited to: iron from hematite (a) the burning of carbon (coke) to provide heat (a) C + O2 → CO2 and produce carbon dioxide (b) C + CO2 → 2CO (b) the reduction of carbon dioxide to carbon (c) Fe2O3 + 3CO → 2Fe + 3CO2 monoxide (d) CaCO3 → CaO + CO2 (c) the reduction of iron(III) oxide by carbon (e) CaO + SiO2 → CaSiO3 monoxide (d) the thermal decomposition of calcium carbonate / limestone to produce calcium oxide (e) the formation of slag Symbol equations are not required 3 State that the main ore of aluminium is bauxite 5 Describe the extraction of aluminium from and that aluminium is extracted by electrolysis purified bauxite / aluminium oxide, including: (a) the role of cryolite (b) why the carbon anodes need to be regularly replaced (c) the reactions at the electrodes, including ionic half-equations Details of the purification of bauxite are not required 26 www.cambridgeinternational.org/igcse Back to contents page  Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 10 Chemistry of the environment 10.1 Water Core Supplement 1 Describe chemical tests for the presence of water using anhydrous cobalt(II) chloride and anhydrous copper(II) sulfate 2 Describe how to test for the purity of water using melting point and boiling point 3 Explain that distilled water is used in practical chemistry rather than tap water because it contains fewer chemical impurities 4 State that water from natural sources may contain substances, including: (a) dissolved oxygen (b) metal compounds (c) plastics (d) sewage (e) harmful microbes (f) nitrates from fertilisers (g) phosphates from fertilisers and detergents 5 State that some of these substances are beneficial, including: (a) dissolved oxygen for aquatic life (b) some metal compounds provide essential minerals for life 6 State that some of these substances are potentially harmful, including: (a) some metal compounds are toxic (b) some plastics harm aquatic life (c) sewage contains harmful microbes which cause disease (d) nitrates and phosphates lead to deoxygenation of water and damage to aquatic life Details of the eutrophication process are not required 7 Describe the treatment of the domestic water supply in terms of: (a) sedimentation and filtration to remove solids (b) use of carbon to remove tastes and odours (c) chlorination to kill microbes Back to contents page www.cambridgeinternational.org/igcse 27 Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 10.2 Fertilisers Core Supplement 1 State that ammonium salts and nitrates are used as fertilisers 2 Describe the use of NPK fertilisers to provide the elements nitrogen, phosphorus and potassium for improved plant growth 10.3 Air quality and climate Core Supplement 1 State the composition of clean, dry air as approximately 78% nitrogen, N2, 21% oxygen, O2 and the remainder as a mixture of noble gases and carbon dioxide, CO2 2 State the source of each of these air pollutants, limited to: (a) carbon dioxide from the complete combustion of carbon-containing fuels (b) carbon monoxide and particulates from the incomplete combustion of carbon-containing fuels (c) methane from the decomposition of vegetation and waste gases from digestion in animals (d) oxides of nitrogen from car engines (e) sulfur dioxide from the combustion of fossil fuels which contain sulfur compounds 3 State the adverse effect of these air pollutants, 7 Describe how the greenhouse gases carbon limited to: dioxide and methane cause global warming, (a) carbon dioxide: higher levels of carbon limited to: dioxide leading to increased global warming, (a) the absorption, reflection and emission of which leads to climate change thermal energy (b) carbon monoxide: toxic gas (b) reducing thermal energy loss to space (c) particulates: increased risk of respiratory problems and cancer (d) methane: higher levels of methane leading to increased global warming, which leads to climate change (e) oxides of nitrogen: acid rain, photochemical smog and respiratory problems (f) sulfur dioxide: acid rain 28 www.cambridgeinternational.org/igcse Back to contents page  Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 10.3 Air quality and climate continued Core Supplement 4 State and explain strategies to reduce the effects of these environmental issues, limited to: (a) climate change: planting trees, reduction in livestock farming, decreasing use of fossil fuels, increasing use of hydrogen and renewable energy, e.g. wind, solar (b) acid rain: use of catalytic converters in 8 Explain how oxides of nitrogen form in car vehicles, reducing emissions of sulfur dioxide engines and describe their removal by catalytic by using low-sulfur fuels and flue gas converters, e.g. 2CO + 2NO → 2CO2 + N2 desulfurisation with calcium oxide 5 Describe photosynthesis as the reaction between carbon dioxide and water to produce glucose and oxygen in the presence of chlorophyll and using energy from light 6 State the word equation for photosynthesis, 9 State the symbol equation for photosynthesis, carbon dioxide + water → glucose + oxygen 6CO2 + 6H2O → C6H12O6 + 6O2 11 Organic chemistry 11.1 Formulae, functional groups and terminology Core Supplement 1 Draw and interpret the displayed formula of a molecule to show all the atoms and all the bonds 2 Write and interpret general formulae of compounds in the same homologous series, limited to: (a) alkanes, CnH2n+2 (b) alkenes, CnH2n (c) alcohols, CnH2n+1OH (d) carboxylic acids, CnH2n+1COOH 3 Identify a functional group as an atom or group of atoms that determine the chemical properties of a homologous series 7 State that a structural formula is an unambiguous description of the way the atoms in a molecule are arranged, including CH2=CH2, CH3CH2OH, CH3COOCH3 8 Define structural isomers as compounds with the same molecular formula, but different structural formulae, including C4H10 as CH3CH2CH2CH3 and CH3CH(CH3)CH3 and C4H8 as CH3CH2CH=CH2 and CH3CH=CHCH3 Back to contents page www.cambridgeinternational.org/igcse 29 Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 11.1 Formulae, functional groups and terminology continued Core Supplement 4 State that a homologous series is a family 9 Describe the general characteristics of a of similar compounds with similar chemical homologous series as: properties due to the presence of the same (a) having the same functional group functional group (b) having the same general formula (c) differing from one member to the next by a –CH2– unit (d) displaying a trend in physical properties (e) sharing similar chemical properties 5 State that a saturated compound has molecules in which all carbon–carbon bonds are single bonds 6 State that an unsaturated compound has molecules in which one or more carbon–carbon bonds are not single bonds 11.2 Naming organic compounds Core Supplement 1 Name and draw the displayed formulae of: 3 Name and draw the structural and displayed (a) methane and ethane formulae of unbranched: (b) ethene (a) alkanes (c) ethanol (b) alkenes, including but-1-ene and but-2-ene (d) ethanoic acid (c) alcohols, including (e) the products of the reactions stated in propan-1-ol, propan-2-ol, butan-1-ol and sections 11.4–11.7 butan-2-ol (d) carboxylic acids containing up to four carbon atoms per molecule 2 State the type of compound present, given a 4 Name and draw the displayed formulae of the chemical name ending in -ane, -ene, -ol, or unbranched esters which can be made from -oic acid or from a molecular formula or unbranched alcohols and carboxylic acids, each displayed formula containing up to four carbon atoms 30 www.cambridgeinternational.org/igcse Back to contents page  Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 11.3 Fuels Core Supplement 1 Name the fossil fuels: coal, natural gas and petroleum 2 Name methane as the main constituent of natural gas 3 State that hydrocarbons are compounds that contain hydrogen and carbon only 4 State that petroleum is a mixture of hydrocarbons 5 Describe the separation of petroleum into useful fractions by fractional distillation 6 Describe how the properties of fractions obtained from petroleum change from the bottom to the top of the fractionating column, limited to: (a) decreasing chain length (b) higher volatility (c) lower boiling points (d) lower viscosity 7 Name the uses of the fractions as: (a) refinery gas fraction for gas used in heating and cooking (b) gasoline / petrol fraction for fuel used in cars (c) naphtha fraction as a chemical feedstock (d) kerosene / paraffin fraction for jet fuel (e) diesel oil / gas oil fraction for fuel used in diesel engines (f) fuel oil fraction for fuel used in ships and home heating systems (g) lubricating oil fraction for lubricants, waxes and polishes (h) bitumen fraction for making roads Back to contents page www.cambridgeinternational.org/igcse 31 Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 11.4 Alkanes Core Supplement 1 State that the bonding in alkanes is single covalent and that alkanes are saturated hydrocarbons 2 Describe the properties of alkanes as being 3 State that in a substitution reaction one atom or generally unreactive, except in terms of group of atoms is replaced by another atom or combustion and substitution by chlorine group of atoms 4 Describe the substitution reaction of alkanes with chlorine as a photochemical reaction, with ultraviolet light providing the activation energy, Ea, and draw the structural or displayed formulae of the products, limited to monosubstitution 11.5 Alkenes Core Supplement 1 State that the bonding in alkenes includes a double carbon–carbon covalent bond and that alkenes are unsaturated hydrocarbons 2 Describe the manufacture of alkenes and hydrogen by the cracking of larger alkane molecules using a high temperature and a catalyst 3 Describe the reasons for the cracking of larger alkane molecules 5 State that in an addition reaction only one product is formed 4 Describe the test to distinguish between 6 Describe the properties of alkenes in terms of saturated and unsaturated hydrocarbons by their addition reactions with: reaction with aqueous bromine (a) bromine or aqueous bromine (b) hydrogen in the presence of a nickel catalyst (c) steam in the presence of an acid catalyst and draw the structural or displayed formulae of the products 32 www.cambridgeinternational.org/igcse Back to contents page  Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 11.6 Alcohols Core Supplement 1 Describe the manufacture of ethanol by: 4 Describe the advantages and disadvantages of (a) fermentation of aqueous glucose at 25–35 °C the manufacture of ethanol by: in the presence of yeast and in the absence of (a) fermentation oxygen (b) catalytic addition of steam to ethene (b) catalytic addition of steam to ethene at 300 °C and 6000 kPa / 60 atm in the presence of an acid catalyst 2 Describe the combustion of ethanol 3 State the uses of ethanol as: (a) a solvent (b) a fuel 11.7 Carboxylic acids Core Supplement 1 Describe the reaction of ethanoic acid with: 2 Describe the formation of ethanoic acid by the (a) metals oxidation of ethanol: (b) bases (a) with acidified aqueous potassium manganate(VII) (c) carbonates (b) by bacterial oxidation during vinegar including names and formulae of the salts production produced 3 Describe the reaction of a carboxylic acid with an alcohol using an acid catalyst to form an ester Back to contents page www.cambridgeinternational.org/igcse 33 Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 11.8 Polymers Core Supplement 1 Define polymers as large molecules built up from 6 Identify the repeat units and / or linkages in many smaller molecules called monomers addition polymers and in condensation polymers 2 Describe the formation of poly(ethene) as an 7 Deduce the structure or repeat unit of an example of addition polymerisation using ethene addition polymer from a given alkene and vice monomers versa 8 Deduce the structure or repeat unit of a condensation polymer from given monomers and vice versa, limited to: (a) polyamides from a dicarboxylic acid and a diamine (b) polyesters from a dicarboxylic acid and a diol 9 Describe the differences between addition and condensation polymerisation 10 Describe and draw the structure of: (a) nylon, a polyamide O O O O O C C N N C C N N C H H H H (b) PET, a polyester O O O O C C O O C C O O The full name for PET, polyethylene terephthalate, is not required 3 State that plastics are made from polymers 4 Describe how the properties of plastics have 11 State that PET can be converted back into implications for their disposal monomers and re-polymerised 5 Describe the environmental challenges caused by plastics, limited to: (a) disposal in land fill sites (b) accumulation in oceans (c) formation of toxic gases from burning 12 Describe proteins as natural polyamides and that they are formed from amino acid monomers with the general structure: R H O N C C H O H H where R represents different types of side chain 13 Describe and draw the structure of proteins as: H O H O N C N C N C H O 34 www.cambridgeinternational.org/igcse Back to contents page  Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 12 Experimental techniques and chemical analysis 12.1 Experimental design Core Supplement 1 Name appropriate apparatus for the measurement of time, temperature, mass and volume, including: (a) stopwatches (b) thermometers (c) balances (d) burettes (e) volumetric pipettes (f) measuring cylinders (g) gas syringes 2 Suggest advantages and disadvantages of experimental methods and apparatus 3 Describe a: (a) solvent as a substance that dissolves a solute (b) solute as a substance that is dissolved in a solvent (c) solution as a mixture of one or more solutes dissolved in a solvent (d) saturated solution as a solution containing the maximum concentration of a solute dissolved in the solvent at a specified temperature (e) residue as a substance that remains after evaporation, distillation, filtration or any similar process (f) filtrate as a liquid or solution that has passed through a filter 12.2 Acid–base titrations Core Supplement 1 Describe an acid–base titration to include the use of a: (a) burette (b) volumetric pipette (c) suitable indicator 2 Describe how to identify the end-point of a titration using an indicator Back to contents page www.cambridgeinternational.org/igcse 35 Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 12.3 Chromatography Core Supplement 1 Describe how paper chromatography is used to 3 Describe how paper chromatography is used separate mixtures of soluble coloured substances, to separate mixtures of soluble colourless using a suitable solvent substances, using a suitable solvent and a locating agent Knowledge of specific locating agents is not required 2 Interpret simple chromatograms to identify: 4 State and use the equation for Rf: (a) unknown substances by comparison with distance travelled by substance Rf = known substances distance travelled by solvent (b) pure and impure substances 12.4 Separation and purification Core Supplement 1 Describe and explain methods of separation and purification using: (a) a suitable solvent (b) filtration (c) crystallisation (d) simple distillation (e) fractional distillation 2 Suggest suitable separation and purification techniques, given information about the substances involved 3 Identify substances and assess their purity using melting point and boiling point information 12.5 Identification of ions and gases Core Supplement 1 Describe tests to identify the anions: (a) carbonate, CO32–, by reaction with dilute acid and then testing for carbon dioxide gas (b) chloride, Cl –, bromide, Br –, and iodide, I –, by acidifying with dilute nitric acid then adding aqueous silver nitrate (c) nitrate, NO3–, reduction with aluminium foil and aqueous sodium hydroxide and then testing for ammonia gas (d) sulfate, SO42–, by acidifying with dilute nitric acid and then adding aqueous barium nitrate (e) sulfite, SO32–, by reaction with acidified aqueous potassium manganate(VII) 36 www.cambridgeinternational.org/igcse Back to contents page  Cambridge IGCSE Chemistry 0620 syllabus for 2023, 2024 and 2025. Subject content 12.5 Identification of ions and gases continued Core Supplement 2 Describe tests using aqueous sodium hydroxide and aqueous ammonia to identify the aqueous cations: (a) aluminium, Al 3+ (b) ammonium, NH4+ (c) calcium, Ca2+ (d) chromium(III), Cr3+ (e) copper(II), Cu2+ (f) iron(II), Fe2+ (g) iron(III), Fe3+ (h) zinc, Zn2+ 3 Describe tests to identify the gases: (a) ammonia, NH3, using damp red litmus paper (b) carbon dioxide, CO2, using limewater (c) chlorine, Cl 2, using damp litmus paper (d) hydrogen, H2, using a lighted splint (e) oxygen, O2, using a glowing splint (f) sulfur dioxide, SO2, using acidified aqueous potassium manganate(VII) 4 Describe the use of a flame test to identify the cations: (a) lithium, Li+ (b) sodium, Na+ (c) potassium, K+ (d) calcium, Ca2+ (e) barium, Ba2+ (f) copper(II), Cu2+ Back to contents page www.cambridgeinternational.org/igcse 37