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Switching to AQA from Edexcel: Chemistry A If you’re thinking of switching to AQA from Edexcel Chemistry A (2CH01) for teaching from September 2016, this resource will provide a helpful comparison of the subject content and assessment for each awarding body. It directly compares the current Edexcel specification, with our new specification (8462) for 2016 onwards. Comparison overview Most of the content is common to both specifications, although the emphasis and style is different. AQA specification has a greater emphasis on the effects of chemistry in our world. There is flexibility to co-teach the Chemistry and Combined Science: Trilogy (8464) courses. Assessment New AQA specification Current Edexcel specification Two externally assessed written papers (1 hour 45 minutes). Paper 1 assesses sections 1 to 5 of the subject content. Paper 2 assesses sections 6 to 10, but may also include the fundamental principles in sections 1 to 3. Eight required practicals should be carried out by students and may be examined in the written papers to assess practical skills. Three externally assessed written papers (1 hour). Paper 1 examines unit C1 Paper 2 examines unit C2 Paper 3 examines unit C3 Controlled assessment is an internal assessment of practical skills. Content Practicals New AQA specification Current Edexcel specification

GCSE Chemistry from Edexcel Chemistry A Switching to AQA

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  • Switching to AQA from Edexcel: Chemistry A If youre thinking of switching to AQA from Edexcel Chemistry A (2CH01) for teaching from September 2016, this resource will provide a helpful comparison of the subject content and assessment for each awarding body. It directly compares the current Edexcel specification, with our new specification (8462) for 2016 onwards.

    Comparison overview Most of the content is common to both specifications, although the emphasis and style is different. AQA specification has a greater emphasis on the effects of chemistry in our world.

    There is flexibility to co-teach the Chemistry and Combined Science: Trilogy (8464) courses.

    Assessment New AQA specification Current Edexcel specification

    Two externally assessed written papers (1 hour 45 minutes).

    Paper 1 assesses sections 1 to 5 of the subject content.

    Paper 2 assesses sections 6 to 10, but may also include the fundamental principles in sections 1 to 3.

    Eight required practicals should be carried out by students and may be examined in the written papers to assess practical skills.

    Three externally assessed written papers (1 hour).

    Paper 1 examines unit C1

    Paper 2 examines unit C2

    Paper 3 examines unit C3

    Controlled assessment is an internal assessment of practical skills.

    Content

    Practicals

    New AQA specification Current Edexcel specification

  • The required practicals are clearly listed, as are opportunities for development of skills identified in the right-hand column of the specification. These should encourage more practical work which will motivate students and encourage the transfer of skills across the subject.

    Each of the three units includes practical investigations which may be externally examined, as well as further suggestions for practical work. Internally assessed controlled assessment tasks are taken from these investigations.

    Working scientifically

    New AQA specification Current Edexcel specification

    Specification reference: WS 1.1 to WS 4.6

    Specification reference: How Science Works

    'Working scientifically' encompasses all the activities that scientists do. It is woven throughout the specification and written papers. There are cross-references to the relevant skills development opportunities in the subject content.

    There is no cross-referencing to Working scientifically skills in the subject content.

    Atomic structure and the periodic table

    4.1.1 A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes

    New AQA specification Current Edexcel specification

    Specification reference:

    4.1.1.1 Atoms, elements and compounds

    Specification reference:

    C1 0.1 to 0.3

    C2.13a

    C2 2.5

    C3 0.4

    C3.5

    This is a summary of the skills which students will need throughout all topics: using names, symbols and various types of equation. Much of this is spread throughout the current Edexcel specification.

  • New AQA specification Current Edexcel specification

    A definition of a compound. Risk assessments for practical work and hazard symbols.

    Specification reference:

    4.1.1.2 Mixtures

    Specification reference:

    C2 3.8 to 3.10

    Both specifications include the separation of mixtures by fractional distillation and chromatography.

    A definition of a mixture, filtration, distillation and simple distillation.

    The separation of two immiscible liquids.

    Specification reference:

    4.1.1.3 Scientific models of the atom

    Specification reference:

    C2 1.3

    Both specifications describe the nuclear model of the atom.

    Description of the historical development of different models of the atom.

    N/A

    Specification reference:

    4.1.1.4 Relative electrical charges of subatomic particles

    Specification reference:

    C2 1.5 to 1.8a

    The content is identical in both specifications.

    Specification reference:

    4.1.1.5 Size and mass of atoms

    Specification reference:

    C2 1.4

    C1.6

    C1.8b

    C1.10

    Both specifications describe the relative sizes of the atom and nucleus and the relative masses of the proton, neutron and electron.

    The actual sizes of the nucleus and atom.

    Isotopes are included for students of all abilities, along with calculation of the number of protons, neutrons and electrons in an atom or ion.

    Higher Tier: the treatment of isotopes. The treatment goes further than AQA, looking at the effect of the existence of isotopes on relative atomic mass.

  • New AQA specification Current Edexcel specification

    Specification reference:

    4.1.1.6 Electronic structure

    Specification reference:

    C2 1.12

    The content is identical in both specifications.

    4.1.2 The periodic table

    New AQA specification Current Edexcel specification

    Specification reference:

    4.1.2.1 The periodic table

    Specification reference:

    C2 1.9

    C1.13

    C4.1

    The content is almost identical in both specifications.

    Prediction of possible reactions and reactivity from position in the periodic table.

    N/A

    Specification reference:

    4.1.2.2. The development of the periodic table

    Specification reference:

    C2 1.1

    Both specifications describe how Mendeleev developed the periodic table.

    Early periodic tables before Mendeleev.

    N/A

    Specification reference:

    4.1.2.3 Metals and non-metals

    Specification reference:

    C2 1.2

    Both specifications describe the position of metals and non-metals in the periodic table.

    The differences between metals and non-metals: ions they form and their characteristic physical and chemical properties.

    N/A

    Specification reference:

    4.1.2.4 Group 0

    Specification reference:

    C2 4.14 to 4.17

  • New AQA specification Current Edexcel specification

    Both specifications cover the lack of reactivity of the noble gases and the trends in physical properties.

    N/A The discovery and uses of the noble gases.

    Specification reference:

    4.1.2.5 Group 1

    Specification reference:

    C2 4.6 to 4.8

    The typical physical properties of the alkali metals and their reaction with water.

    Low density of the metals, colour and solubility of compounds.

    Higher Tier: explanation of the pattern of reactivity.

    Specification reference:

    4.1.2.6 Group 7

    Specification reference:

    C2 4.9 to 4.13

    Both specifications cover:

    the reaction of the halogens with metals and non-metals

    displacement reactions of halogens with metal halides leading to the trend in reactivity.

    The trend in relative molecular mass, melting point and boiling point and the existence as diatomic molecules.

    The reaction of metals includes the formation of ions with a -1 charge. The reaction with non-metals is more general.

    Recall of colours and physical states of the halogens at room temperature.

    The reaction with non-metals is restricted to the reaction with hydrogen to produce hydrogen halides which form acids in water.

    Displacement reactions of halogens is a required practical.

    4.1.3 Properties of transition elements

    New AQA specification Current Edexcel specification

    Specification reference:

    4.1.3.1 Comparison with Group 1 elements

    Specification reference:

    C2 4.4a

  • New AQA specification Current Edexcel specification

    Both specifications include a comparison of melting points of transition metals and Group 1 elements.

    A comparison of strength and relative reactivity with Group 1 elements. The properties are exemplified by reference to six specified transition metals.

    N/A

    Specification reference:

    4.1.3.2 Typical properties

    Specification reference:

    C2 4.4b

    Both specifications include the formation of coloured compounds by transition metals.

    The formation of ions with different charges and catalytic activity exemplified by reference to six specified transition metals.

    N/A

    Bonding, structure and the properties of matter

    4.2.1 Chemical bonds, ionic, covalent and metallic

    New AQA specification Current Edexcel specification

    Specification reference:

    4.2.1.1 Chemical bonds

    Specification reference:

    C2 2.1

    Introduction to the types of bonding. The detailed content is spread throughout the Edexcel specification, but its not summarised in the same way as in the AQA specification.

    Specification reference:

    4.2.1.2 Ionic bonding

    Specification reference:

    C2 2.2 to 2.5

    Both specifications deal with ionic bonding as electron transfer, using sodium chloride as an example.

    The relation of charge on the ions to the group number.

    the terms cation and anion

    ions as charged groups of atoms

    the endings -ide and -ate in names of compounds.

  • New AQA specification Current Edexcel specification

    Specification reference:

    4.2.1.3 Ionic compounds

    Specification reference:

    C2 2.7 (Higher Tier only)

    The description of an ionic compound as a lattice, with strong electrostatic forces, is included in both specifications, but is only for Higher Tier in the Edexcel specification, unlike AQA.

    Dot-and-cross, ball-and-stick, and space-filling diagrams, with a consideration of their limitations. Students are expected to deduce that a compound is ionic and to deduce the empirical formula from a diagram.

    N/A

    Specification reference:

    4.2.1.4 Covalent bonding

    Specification reference:

    C2 3.1 to 3.3

    The description of covalent bonding, as sharing of pairs of electrons, is very similar in both specifications. However, the examples are different, and two of the Edexcel examples are for Higher Tier only.

    Both specifications include dot-and-cross diagrams.

    Large molecules, such as polymers and giant structures, including silicon dioxide.

    The limitations of different types of diagram, including ball-and-stick, 2D and 3D representations. Students are expected to deduce the molecular formula of a substance from a given model or diagram.

    N/A

    Specification reference:

    4.2.1.5 Metallic bonding

    Specification reference:

    C2 4.2

    The content is almost the same. AQA specification emphasises 2D and 3D representations.

    4.2.2 How bonding and structure are related to the properties of substances

    New AQA specification Current Edexcel specification

  • New AQA specification Current Edexcel specification

    Specification reference:

    4.2.2.1 The three states of matter

    N/A

    Description of the particle model of the three states of matter and changes of state. It includes the prediction of the state of a substance at different temperatures (given appropriate data).

    This topic is not covered, however understanding of most of the ideas is assumed in other areas, such as covalent compounds C2 3.4, 3.5, 3.9 and gases, equilibria and ammonia, C3 4.

    Specification reference:

    4.2.2.2 State symbols

    Specification reference:

    C1

    C2

    C3 0.3

    The content is identical in both specifications.

    Specification reference:

    4.2.2.3 Properties of ionic compounds

    Specification reference:

    C2 2.7 to 2.8

    C4.5

    Both specifications describe and explain the high melting and boiling point and electrical conductivity of ionic substances.

    Edexcel Higher Tier: the explanation of the properties.

    AQA has the description and the explanation for students of all abilities.

    Specification reference:

    4.2.2.4 Properties of small molecules

    Specification reference:

    C2 3.5

    C4.5

    Both specifications describe and explain the low melting and boiling point and lack of electrical conductivity of substances consisting of small molecules.

    Intermolecular forces increase with size of molecules.

    N/A

    Specification reference:

    4.2.2.5 Polymers

    N/A

  • New AQA specification Current Edexcel specification

    The size of the molecules, the strength of bonding and intermolecular forces of polymers linked to their properties as solids at room temperature.

    N/A

    Specification reference:

    4.2.2.6 Giant covalent structures

    Specification reference:

    C2 3.6

    C4.5

    Both specifications deal with the difference between simple molecular and giant covalent substances. Both refer to diamond and graphite. AQA specification also includes silicon dioxide.

    Specification reference:

    4.2.2.7 Properties of metals and alloys

    Specification reference:

    C1 4.10 to 4.11

    C2 4.3

    C4.5

    Both specifications use models to explain the difference in properties between pure metals and alloys.

    The strength of metallic bonding is linked to most metals having high melting and boiling points.

    Edexcel covers here uses of metals in relation to their properties (AQA has this topic in section 4.10.3.2).

    Specification reference:

    4.2.2.8 Metals as conductors

    Specification reference:

    C2 4.3

    Both specifications describe and explain electrical conductivity.

    AQA describes and explains conduction of thermal energy.

    N/A

    N/A Section 4.5 classifies elements and compounds as four main structure types, with their properties.

    Edexcel also includes relative solubility in water.

    There is a required practical investigation of structure type.

  • 4.2.3 Structure and bonding of carbon

    New AQA specification Current Edexcel specification

    Specification reference:

    4.2.3.1 Diamond

    Specification reference:

    C2 3.7

    C4.5

    The content is almost identical. Edexcel specification includes use of diamond in cutting tools (Higher Tier).

    Specification reference:

    4.2.3.2 Graphite

    Specification reference:

    C2 3.7

    C4.5

    The content is almost identical in both specifications.

    The conduction of thermal energy. Higher Tier: the use of graphite as electrodes and a lubricant.

    Specification reference:

    4.2.3.3 Graphene and fullerenes

    N/A

    4.2.4 Bulk and surface properties of matter including nanoparticles

    New AQA specification Current Edexcel specification

    Specification reference:

    4.2.4.1 Sizes of particles and their properties

    N/A

    Specification reference:

    4.2.4.2 Uses of nanoparticles

    N/A

    Quantitative chemistry

    4.3.1 Conservation of mass and the quantitative interpretation of chemical equations

    New AQA specification Current Edexcel specification

    Specification reference:

    4.3.1.1 Conservation of mass and balanced chemical equations

    Specification reference:

    C1 2.13 b

    C1.2.13c

  • New AQA specification Current Edexcel specification

    C2.16

    There is no clear link between conservation of mass and balanced chemical equations in the Edexcel specification.

    Specification reference:

    4.3.1.2 Relative formula mass

    Specification reference:

    C2 6.1

    There is no clear link between the sum of the relative formula masses and balanced chemical equations in the Edexcel specification.

    Specification reference:

    4.3.1.3 Mass changes when a reactant or product is a gas

    N/A

    4.3.2 Uses of amount of substance in relation to masses of pure substances

    New AQA specification Current Edexcel specification

    Specification reference:

    4.3.2.1 Moles

    Specification reference:

    C3 2.7 to 2.8

    Higher Tier content in both specifications.

    Avogadro constant and the mole applied to formulae, equations and particles.

    N/A

    Specification reference:

    4.3.2.2 Amounts of substances in equations

    Specification reference:C2 6.5

    Higher Tier content in both specifications.

    Specification reference:

    4.3.2.3 Using moles to balance equations (Higher Tier only)

    N/A

    Specification reference:

    4.3.2.4 Limiting reactants (Higher Tier only)

    N/A

  • New AQA specification Current Edexcel specification

    Specification reference:

    4.3.2.5 Concentration of solutions

    Specification reference:

    C3 2.1

    Higher Tier: AQA

    Students of all abilities: Edexcel.

    4.3.3 Yield and atom economy of chemical reactions

    New AQA specification Current Edexcel specification

    Specification reference:

    4.3.3.1 Percentage yield

    Specification reference:

    C2 6.6 to 6.9

    Both specifications require a calculation of percentage yield. They give reasons for a yield being less than 100% (AQA reason is reversible reactions not going to completion).

    Specification reference:

    4.3.3.2 Atom economy

    This topic is not covered in the Edexcel specification.

    However, in sections C2 6.10 to C6.11 the specification includes an understanding of waste products and their problems and chemists in industry working to find the economically most favourable reactions.

    4.3.4 Using concentrations of solutions in mol/dm3

    New AQA specification Current Edexcel specification

    Specification reference:

    4.3.4 Using concentrations of solutions in mol/dm3

    Specification reference:

    C3 2.9

    C2.13 to 2.15

    Both specifications describe a titration and carry out calculations.

    AQA: whole topic is Higher Tier only.

    Edexcel: only calculations are Higher Tier; a description of a titration is for students of all abilities.

  • 4.3.5 Use of amount of substance in relation to volumes of gases

    New AQA specification Current Edexcel specification

    Specification reference:

    4.3.5 Use of amount of substance in relation to volumes of gases

    Specification reference:

    C3 4.1 to 4.3

    Higher Tier content in both specifications.

    Calculation of the volume of a gas from its mass and relative formula mass.

    Calculations involving balanced equations, masses of solids and volumes of gases.

    Chemical changes

    4.4.1 Reactivity of metals

    New AQA specification Current Edexcel specification

    Specification reference:

    4.4.1.1 Metal oxides

    Specification reference:

    C1 4.5

    Both specifications define oxidation and reduction as gain and loss of oxygen. Only the AQA specification refers to the reaction of metals with oxygen.

    Specification reference:

    4.4.1.2 The reactivity series

    This topic is not covered in the Edexcel specification, although reference is made to the reactivity series in the context of metal extraction in C1 4.3

    Specification reference:

    4.4.1.3 Extraction of metals and reduction

    Specification reference:

    C1 4.1 to 4.6

    The emphasis is on carbon reduction and position in the reactivity series. Extraction by electrolysis (aluminium) is included here in the Edexcel specification, but covered in the Electrolysis topic in the AQA specification.

    N/A A practical investigation of methods for extracting a metal from its ore.

    Specification reference:

    4.4.1.4 Oxidation and reduction in

    Specification reference:

    C3 3.3

  • New AQA specification Current Edexcel specification

    terms of electrons

    AQA: Higher Tier only.

    Edexcel specification includes this topic only in the context of electrolysis, while AQA includes displacement reactions.

    Ionic equations for displacement reactions.

    N/A

    4.4.2 Reactions of acids

    New AQA specification Current Edexcel specification

    Specification reference:

    4.4.2.1 Reactions of acids with metals

    N/A

    Specification reference:

    4.4.2.2 Neutralisation of acids and salt production

    Specification reference:

    C1 3.4 to 3.5

    C2 2.6

    The content is the same in both specifications.

    Specification reference:

    4.4.2.3 Soluble salts

    Specification reference:

    C3 2.10 to 11

    C2.14

    Both specifications cover the preparation of a soluble salt from an acid and an insoluble starting material.

    Crystallisation of solutions to produce solid salts.

    There is a required practical to prepare a soluble salt from an insoluble oxide or carbonate.

    Preparation of a soluble salt by titration, including a required practical.

    Specification reference:

    4.4.2 4 The pH scale and neutralisation

    Specification reference:

    C3 2.12

  • New AQA specification Current Edexcel specification

    Both specifications describe neutralisation as reaction between hydrogen ions and hydroxide ions.

    pH scale from 0 to 14, the use of universal indicator and pH probes.

    Titration is the required practical.

    Sections C1 3.1 to C3.3, cover the production of hydrochloric acid in the stomach and indigestion remedies, including a required practical investigation.

    Specification reference:

    4.4.2.5 Strong and weak acids

    N/A

    4.4.3 Electrolysis

    New AQA specification Current Edexcel specification

    Specification reference:

    4.4.3.1 The process of electrolysis

    Specification reference:

    C3 3.1 to 3.2

    C3.5

    Higher Tier in both specifications: Writing half equations.

    Specification reference:

    4.4.3.2 Electrolysis of molten ionic compounds

    Specification reference:

    C3 3.11d

    The content is based on lead bromide as an example.

    Prediction of the products of electrolysis of molten binary ionic compounds.

    N/A

    Specification reference:

    4.4.3.3 Using electrolysis to extract metals

    Specification reference:

    C1 4.2b

    C3 3.6 to 3.7

    The AQA specification includes details of the extraction of aluminium. The Edexcel specification requires only the knowledge of electrolysis use.

    N/A The manufacture of sodium and uses of sodium.

  • New AQA specification Current Edexcel specification

    Specification reference:

    4.4.3.4 Electrolysis of aqueous solutions

    Specification reference:

    C1 3.6 to 3.7

    C3.13

    C3 3.8 to 3.11

    The topic is treated differently in the two specifications: AQA focuses on principles and Edexcel on examples.

    Rules for which product is produced at each electrode, leading to prediction of the products of electrolysis of aqueous solutions containing a single ionic compound.

    There is a required practical investigating the electrolysis of solutions with inert electrodes.

    Electrolysis of hydrochloric acid (without explanation of the electrode products), including a required practical.

    It also includes:

    the electrolysis of sea water and uses of the products

    the decomposition of water by electrolysis

    the electrolysis of sodium chloride, copper chloride, copper sulfate, sodium sulfate

    a required practical including mass changes of copper electrodes in electrolysis of copper sulfate solution

    the purification of copper using copper electrodes

    electroplating.

    Specification reference:

    4.4.3.5 Representation of reactions at electrodes as half-equations

    Specification reference:

    C3 3.3 to 3.5

    AQA: Higher Tier only.

    Edexcel: only writing half-equations is at Higher Tier. Description of redox in terms of electron transfer is for students of all abilities.

  • Energy changes

    4.5.1 Exothermic and endothermic reactions

    New AQA specification Current Edexcel specification

    Specification reference:

    4.5.1.1 Energy transfer during exothermic and endothermic reactions

    Specification reference:

    C 5.1 to 5.3

    Both specifications include a required practical, although these have different aims and use different examples.

    Conservation of energy during reactions. Uses and applications of exothermic and endothermic reactions.

    N/A

    Specification reference:

    4.5.1.2 Reaction profiles

    Specification reference:

    C2 5.6

    Edexcel: Higher Tier only; the content does not include knowledge of activation energy.

    Specification reference:

    4.5.1.3 The energy change of reactions

    Specification reference:

    C3 5.4

    C5.5

    Both specifications include a description of bond breaking as being endothermic and bond making as exothermic, with the consequent effect on the overall energy change.

    AQA: Higher Tier only.

    Edexcel: students of all abilities.

    Calculation of energy transfer from bond energies.

    A required practical comparing the temperature rise when the same volume of water is heated by different fuels (C1 5.24).

    4.5.2 Chemical cells and fuel cells

    New AQA specification Current Edexcel specification

    Specification reference:

    4.5.2.1 Cells and batteries

    N/A

  • New AQA specification Current Edexcel specification

    Specification reference:

    4.5.2.2 Fuel cells

    Specification reference:

    C1 5.21

    The majority of this topic is not covered in the Edexcel specification. It requires knowledge that energy can be provided by a simple hydrogen-oxygen fuel cell.

    The rate and extent of chemical change

    4.6.1 Rate of reaction

    New AQA specification Current Edexcel specification

    Specification reference:

    4.6.6.1 Calculating rates of reactions

    N/A

    Specification reference:

    4.6.1.2 Factors which affect the rates of chemical reactions

    Specification reference:

    C2 5.8 to 5.9

    C5.12

    The content is very similar in the two specifications. Both include a required practical, although this is restricted to the effect of concentration changes in the AQA specification.

    The effect of gas pressure, the idea of surface area to volume ratio for solids and three specific methods for investigating rates.

    Knowledge that reaction rates can vary from very fast to very slow.

    Specification reference:

    4.6.1.3 Collision theory and activation energy

    Specification reference:

    C2 5.10 to 5.11

    Both specifications deal with the effect of changing the frequency and energy of particle collisions.

    AQA: the whole topic is for students of all abilities.

    Edexcel: all content is Higher Tier, except the idea that reactions occur when particles collide.

  • New AQA specification Current Edexcel specification

    An explanation of the effect of changing temperature, concentration and pressure in terms of collision theory, including the idea of activation energy.

    An explanation of the effect on rate of changing size of pieces of solid, in terms of surface area to volume ratio.

    The Edexcel specification is less specific.

    Specification reference:

    4.6.1.4 Factors that increase the rate of reaction

    Specification reference:

    C2 5.10 to 5.11

    The content is very similar, although the Edexcel specification is less detailed. The AQA specification is for students of all abilities, whereas it is Higher Tier only in the Edexcel specification.

    Use of simple ideas about proportionality when using collision theory.

    N/A

    Specification reference:

    4.6.1.5 Catalysts

    Specification reference:

    C2 5.12 to 5.13

    The AQA specification is much more detailed. Only the recall of the effect of a catalyst on a reaction rate is common to both specifications.

    The definition of a catalyst, specificity of catalysts, enzymes as catalysts, an explanation of catalytic action in terms of lowering activation energy and the effect of a catalyst on a reaction profile.

    The use of catalytic converters in cars.

    4.6.2 Reversible reactions and dynamic equilibrium

    New AQA specification Current Edexcel specification

    Specification reference:

    4.6.2.1 Reversible reactions

    Specification reference:

    C3 4.6

    This brief introduction is common to both specifications. Reference to

  • New AQA specification Current Edexcel specification

    the fact that changing conditions alters the position of equilibrium (without any detail) is for students of all abilities in the AQA specification. Edexcel covers this topic in detail at Higher Tier only.

    Specification reference:

    4.6.2.2 Energy changes and reversible reactions

    Specification reference:

    C3 4.8

    This topic, using hydrated and anhydrous copper sulfate as an example, is included in the AQA specification for students of all abilities. It is implicit in section 4.8a of the Edexcel specification, but only at Higher Tier.

    Specification reference:

    4.6.2.3 Equilibrium

    Specification reference:

    C3 4.7

    This topic is very similar (Higher Tier only in both specifications).

    Emphasis of the need for a closed system.

    N/A

    Specification reference:

    4.6.2.4 The effect of changing conditions on equilibrium

    Specification reference:

    C3 4.8

    Both specifications require knowledge of how conditions affect equilibrium position at Higher Tier. However, only the AQA specification does this in terms of Le Chatelier's principle.

    Specification reference:

    4.6.2.5 The effect of changing concentration (Higher Tier only)

    N/A

    Specification reference:

    4.6.2.6 The effect of temperature changes on equilibrium

    Specification reference:

    C3 4.8a

    The content is the same in both specifications.

    Specification reference:

    4.6.2.7 The effect of pressure changes on equilibrium

    Specification reference:

    C3 4.8b

    The content is the same in both specifications.

  • Organic chemistry

    4.7.1 Carbon compounds as fuels and feedstock

    New AQA specification Current Edexcel specification

    Specification reference:

    4.7.1.1 Crude oil, hydrocarbons and alkanes

    Specification reference:

    C1 5.1 to 5.2

    C5.25 to 5.26

    C3 5.9 to 5.10a

    The content is very similar, although the general formula for alkanes is only implicit in the Edexcel specification.

    The formation of crude oil and recognition of other substances as alkanes from their formula.

    The Edexcel specification includes, in section C3 5.9, a definition of a homologous series, which is not explicit in the AQA specification.

    Specification reference:

    4.7.1.2 Fractional distillation and petrochemicals

    Specification reference:

    C1 5.3 to 5.4

    The content is very similar in both specifications.

    AQA requires explaining fractional distillation, along with an awareness of the vast array of natural and synthetic carbon compounds. There is reference to solvents, lubricants, polymers and detergents as derivatives of crude oil.

    Edexcel doesnt require details of fractional distillation, but asks for uses of different fractions, including bitumen (not mentioned in the AQA specification).

    Specification reference:

    4.7.1.3 Properties of hydrocarbons

    Specification reference:

    C1 5.5 to 5.6

    The content is almost identical. Writing balanced equations for combustion reactions is for Higher Tier only in the Edexcel specification. AQA has the whole topic for students of all abilities.

    Specification reference:

    4.7.1.4 Cracking and alkenes

    Specification reference:

    C1 5.29 to 32

    The content is very similar. However, the Edexcel specification requires a description of cracking in the laboratory while AQA requires knowledge of the industrial conditions. Writing balanced equations for cracking

  • New AQA specification Current Edexcel specification

    reactions is Higher Tier only in the Edexcel specification, unlike AQA where it is for students of all abilities.

    Alkenes as starting materials for many other chemicals.

    Modern life depending on the uses of hydrocarbons (the Edexcel specification only refers to polymers).

    The use of data on the composition of different crude oils and demand for the fractions is required for Higher Tier only.

    4.7.2 Reactions of alkenes and alcohols

    New AQA specification Current Edexcel specification

    Specification reference:

    4.7.2.1 Structure and formulae of alkenes

    Specification reference:

    C1 5.27 to 5.28

    C3 5.9

    C5.10b

    The content is very similar in both specifications. However, the AQA specification covers more alkenes; the general formula for alkenes is only implicit in the Edexcel specification.

    Recognition of substances as alkenes from their names or given formulae.

    N/A

    Specification reference:

    4.7.2.2 Reactions of alkenes

    Specification reference: C3 5.6

    The AQA specification requires many more reactions; only the reaction of ethene with steam is common to both. That reaction is Higher Tier at Edexcel, unlike at AQA.

    Reactions of alkenes with oxygen (including incomplete combustion), hydrogen and halogens.

    N/A

    Specification reference:

    4.7.2.3 Alcohols

    Specification reference:

    C3 5.1 to 5.9

    C5.10c

  • New AQA specification Current Edexcel specification

    C5.11

    Only the names, formulae and structures of alcohols are common to both specifications (but are at Higher Tier only in the Edexcel specification).The AQA specification includes one more alcohol.

    Neutral solutions in water, reaction with sodium, combustion, use as fuels and solvents. Recognition of other substances as alcohols from their names or formulae.

    A required practical to make ethanol by fermentation and obtaining a concentrated solution of ethanol by fractional distillation of the fermentation mixture (for students of all abilities).

    A consideration of the different alcohol content in various drinks, the social issues and possible harmful effects of drinking alcohol. Oxidation of open bottles of wine, production of vinegar.

    Higher Tier: evaluation of two different methods of manufacturing ethanol; dehydration of ethanol.

    Specification reference:

    4.7.2.4 Carboxylic acids

    Specification reference:

    C5 5.

    C5.10d

    C5.12 to 5.14

    The names, formulae and structures of carboxylic acids are common to both specifications (but are at Higher Tier only in the Edexcel specification). The AQA specification includes one more acid.

    Both specifications also cover reaction with metal carbonates and esterification.

    Understanding that acids are weak because of incomplete ionisation in water. Recognition of other substances as carboxylic acids from their names or formulae.

    No balanced equations are required in this topic.

    The uses of vinegar as flavouring and a preservative. Reactions of ethanoic acid with metals and with bases to form ethanoate salts.

    Higher Tier: equation for the formation of ethyl ethanoate using molecular and structural formulae.

  • 4.7.3 Synthetic and naturally occurring polymers

    New AQA specification Current Edexcel specification

    Specification reference:

    4.7.3.1 Addition polymerisation

    Specification reference:

    C1 5.33 to 5.37

    The content is similar in both specifications, although equations are at Higher Tier only in the Edexcel specification, unlike at AQA.

    A definition of addition polymerisation.

    Poly(chloroethene) and PTFE. Uses of the specified polymers related to their properties.

    The problems of disposal of polymers and how they can be overcome.

    Specification reference:

    4.7.3.2 Condensation polymerisation (Higher Tier only)

    N/A

    Specification reference:

    4.7.3.3 Amino acids (Higher Tier only)

    N/A

    Specification reference:

    4.7.3.4 DNA and other naturally occurring polymers (Higher Tier only)

    N/A

    Chemical analysis

    4.8.1 Purity, formulations and chromatography

    New AQA specification Current Edexcel specification

    Specification reference:

    4.8.1.1 Pure substances

    N/A

    Specification reference:

    4.8.1.2 Formulations

    N/A

    Specification reference:

    4.8.1.3 Chromatography

    Specification reference:

    C2 3.10 to 11

  • The content is similar in both specifications: calculation requirement of Rf values.

    An explanation of how chromatography works, including stationary phase and mobile phase. Reference to different solvents.

    There is a required practical on chromatography and calculation of Rf values.

    The topic is dealt with in the contexts of the food industry and forensic science.

    4.8.2 Identification of common gases

    New AQA specification Current Edexcel specification

    Specification reference:

    4.8.2.1 Test for hydrogen

    Specification reference: C1 3.8

    Specification reference:

    4.8.2.2 Test for oxygen

    Specification reference: C1 3.14

    Specification reference:

    4.8.2.3 Test for carbon dioxide

    Specification reference: C1 5.7

    Specification reference:

    4.8.2.4 Test for chlorine

    Specification reference: C1 3.9

    The content for all four tests is identical in both specifications.

    4.8.3 Identification of ions by chemical and spectroscopic means

    New AQA specification Current Edexcel specification

    Specification reference:

    4.8.3.1 Flame tests

    Specification reference: C2 2:15a

    The content is almost identical. The AQA specification includes one more metal ion (lithium).

    Specification reference:

    4.8.3.2 Metal hydroxides

    Specification reference: C3 1.3a

    The content is almost identical. The AQA specification includes one more metal ion (magnesium). The Edexcel section C3 1.3b also gives a test for

  • New AQA specification Current Edexcel specification

    ammonium ions, which is not covered in the AQA specification.

    Specification reference:

    4.8.3.3 Carbonates

    Specification reference:

    C2 2.9e

    C2.15b

    The content is almost identical in both specifications.

    Specification reference:

    4.8.3.4 Halides

    Specification reference:

    C2 2.15d

    C3 1.3c

    The content is identical in both specifications.

    Specification reference:

    4.8.3.5 Sulfates

    Specification reference: C2 2.15c

    The content is identical in both specifications.

    Specification reference:

    4.8.3.6 Instrumental methods

    Specification reference: C2 2.16

    The AQA specification gives the advantages of instrumental techniques in general. The Edexcel specification only includes flame spectroscopy.

    Specification reference:

    4.8.3.7 Flame emission spectroscopy

    Specification reference: C2 2.16

    Both specifications mention the technique, but with different purposes.

    The process is described, along with the production of a spectrum, which students must be able to interpret given appropriate data.

    The focus is the use of the technique to detect elements. Use in the discovery of new elements is also mentioned.

    Both specifications include a required practical to identify the ions in a single ionic compound.

  • New AQA specification Current Edexcel specification

    N/A The Edexcel specification includes:

    understanding of the difference between qualitative and quantitative analysis

    the idea that the test for any ion must be unique

    understanding that these tests can be used to check the purity of drinking water and to detect the presence of substances in the blood.

  • Chemistry of the atmosphere

    4.9.1 The composition and evolution of the Earth's atmosphere

    New AQA specification Current Edexcel specification

    Specification reference:

    4.9.1.1 The proportions of different gases in the atmosphere

    Specification reference:

    C1 1.7 to 1.9a

    The content is almost identical in both specifications.

    N/A A required practical to investigate the proportion of oxygen in the atmosphere.

    Specification reference:

    4.9.1.2 The Earth's early atmosphere

    Specification reference:

    C1 1.1 to 1.5

    The content is almost identical in both specifications.

    The presence of nitrogen, methane and ammonia.

    N/A

    Specification reference:

    4.9.1.3 How oxygen increased

    Specification reference: C1 1.6

    The content is identical in both specifications.

    Specification reference:

    4.9.1.4 How carbon dioxide decreased

    Specification reference: C1 1.6

    The content is almost identical in both specifications.

    AQA specification refers to the formation of coal, crude oil and limestone. Edexcel specification refers only to limestone.

    4.9.2 Carbon dioxide and methane as greenhouse gases

    New AQA specification Current Edexcel specification

    Specification reference:

    4.9.2.1 Greenhouse gases

    Specification reference: C1 5.13

  • New AQA specification Current Edexcel specification

    The content is similar, but the AQA specification is more detailed, describing the greenhouse effect in terms of the interaction of radiation of different wavelengths with matter.

    Specification reference:

    4.9.2.2 Human activities which contribute to an increase of greenhouse gases in the atmosphere.

    Specification reference:

    C1 1.9b

    C5.14

    C5.16

    The content is very similar, but the AQA specification includes the decomposition of rubbish in landfill sites contributing to an increase in greenhouse gases.

    Specification reference:

    4.9.2.3 Global climate change

    N/A

    Specification reference:

    4.9.2.4 The carbon footprint and its reduction

    Specification reference:

    C1 5.15

    C5.17 to 5.19

    C5.22 to 5.23

    The methods of reduction of carbon footprint are different in the two specifications.

    A definition of carbon footprint, the ideas of energy conservation, carbon taxes and licenses, carbon off-setting and carbon neutrality, problems of reducing the carbon footprint.

    Iron seeding of oceans, biofuels as an alternative to fossil fuels and hydrogen as an alternative to petrol as a fuel in cars.

    4.9.3 Common atmospheric pollutants and their sources

    New AQA specification Current Edexcel specification

    Specification reference:

    4.9.3.1 Atmospheric pollutants from fuels

    Specification reference:

    C1 5.8

    C5.11

    Both specifications deal with the production of carbon, carbon monoxide and sulfur dioxide.

  • New AQA specification Current Edexcel specification

    Coal as a fuel, the production of oxides of nitrogen and prediction of the combustion products of a fuel (given appropriate information).

    N/A

    Specification reference:

    4.9.3.2 Properties and effects of atmospheric pollutants

    Specification reference:

    C1 5.9 to 5.10 and 5.12

    The content is similar in both specifications, although the AQA specification includes more effects.

    Respiratory problems caused by sulfur dioxide and oxides of nitrogen, oxides of nitrogen causing acid rain and the effects of particulates.

    The context of incomplete combustion in appliances using carbon compounds as fuels.

    N/A Factors that make a good fuel (section C1 5.20)

    Using resources

    4.10.1 Using the Earth's resources and obtaining potable water

    New AQA specification Current Edexcel specification

    Specification reference:

    4.10.1.1 Using the Earth's resources and sustainable development

    There is no equivalent topic in the Edexcel specification, although sections C1 5.18 to 5.23 touch on some of the principles.

    Specification reference:

    4.10.1.2 Potable water

    N/A

    Specification reference:

    4.10.1.3 Waste water treatment

    N/A

    Specification reference:

    4.10.1.4 Alternative methods of extracting metals

    N/A

  • 4.10.2 Life cycle assessment and recycling

    New AQA specification Current Edexcel specification

    Specification reference:

    4.10.2.1 Life cycle assessment

    N/A

    Specification reference:

    4.10.2.2 Ways of reducing the use of resources

    Specification reference:

    C1 4.9

    Most of this topic is not covered in the Edexcel specification it only covers recycling of metals.

    4.10.3 Using materials

    New AQA specification Current Edexcel specification

    Specification reference:

    4.10.3.1 Corrosion and its prevention

    Specification reference:

    C1 4.7 to 4.

    Both specifications discuss corrosion of metals.

    The conditions needed for rusting and corrosion prevention methods, including corrosion inhibitors and sacrificial protection. The protective oxide layer on aluminium.

    The main focus is the relation of a metal's resistance to corrosion to its position in the reactivity series. Prevention of corrosion is not covered.

    Specification reference:

    4.10.3.2 Alloys as useful materials

    Specification reference:

    C1 4.12 to 4.14

    Both specifications cover the reasons for alloying metals, steels and alloys of gold including carats (gold is Higher Tier only in the Edexcel specification). Other alloys covered are different.

    Alloys of copper and aluminium. Higher Tier: shape memory alloys; the proportion of gold in alloys is indicated by fineness and carats.

    Specification reference:

    4.10.3.3 Ceramics, polymers and composites

    N/A

  • 4.10.4 The Haber process and the use of NPK fertilisers

    New AQA specification Current Edexcel specification

    Specification reference:

    4.10.4.1 The Haber process

    Specification reference:

    C3 4.9 to 4.10

    Both specifications refer to the equilibrium reaction for the process, referring back to the principles of equilibrium and the need to produce an acceptable rate in an acceptable time.

    Edexcel Higher Tier: whole topic.

    AQA Higher Tier: only the application of the principles of equilibrium and the need for compromise conditions.

    For students of all abilities:

    the raw materials and their sources

    the precise conditions used in industry

    how the ammonia is removed from the reaction mixture.

    N/A

    Specification reference:

    4.10.4.2 Production and uses of NPK fertilisers

    Specification reference:

    C3 4.4 to 4.5

    Both specifications refer to the production of fertilisers from ammonia.

    The presence of compounds of potassium and phosphorus. It covers mining for potassium salts and phosphate rock, the treatment of phosphate rock and a comparison of the industrial production of fertilisers with laboratory preparations of the same compounds.

    Nitrogenous fertilisers only.

    The environmental consequences of the overuse of fertilisers.

    Edexcel content no longer required

    The following topics are not included in the new DfE subject content:

    Specification reference: C1 2.1 to 2.6

    Igneous, sedimentary and metamorphic rocks

  • Specification reference: C1 2.17 to 2.12, 2.14 to 2.15, 2.17 to 2.18

    Limestone, decomposition of metal carbonates, calcium oxide and calcium hydroxide

    Specification reference: C2 2.9 to 2.14

    Solubility rules for common types of substance, preparation of insoluble salts by precipitation, uses of barium sulfate

    Edexcel specification reference: C3 2.2 to 2.6

    Hard water