gcse chemistry from ocr b switching to aqa

Switching to AQA from OCR Chemistry B

If you're thinking of switching to AQA from OCR GCSE in Chemistry B (Gateway

Science - J264) 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 OCR Chemistry B specification, with the new

specification (8462) for 2016 onwards.

Comparison overview

Although both specifications are organised by concept, these concepts have been

grouped into different topics. This means that the content in the AQA

specification can be found in several OCR topics. AQA and OCR also give different

emphasis to specific topics.

There is flexibility to co-teach the AQA Chemistry and Combined Science: Trilogy

(8464) courses.

Assessment

New AQA specification Current OCR 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 exam papers overall.

Two externally assessed written

papers:

One paper of 1 hour 15

minutes. Covering content in

modules C1, C2 and C3 (35%

of qualification).

One paper of 1 hour 30

minutes. Covering content in

modules C4, C5 and C6.

Includes 10 mark data

response question (40% of

qualification).

One controlled assessment exam

paper (25% of qualification).

Content

Practicals


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.

Opportunities for practical work are

flagged in the introduction to each

module.

Working scientifically


Specification reference: WS 1.1 to

WS 4.6

Specification reference: Ideas about

science

'Working scientifically' encompasses

all the activities that scientists do. It

is woven throughout the

specification and written papers.

There are cross-references to

relevant skills development

opportunities in the subject

content.

N/A

Atomic structure and the periodic table

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

charge and isotopes


Specification reference:

4.1.1.1 Atoms, elements and

compounds


C4: Fundamental Concepts

Both specifications require recognition and manipulation of chemical

symbols and formulae to describe molecular composition and reactions

using an understanding of atoms and molecules, elements and

compounds.


Equations and balancing can be found at Foundation Tier in both

specifications.

The OCR specification refers to recollection of particular compounds'

formulae in an introductory item for each topic entitled 'Fundamental

Chemical Concepts'.

Recognition of symbols of the first

20 elements.

N/A


4.1.1.2 Mixtures


Fundamental Concepts: C4

There is no equivalent summary topic in the OCR specification, although all

of the separation techniques are covered throughout the specification.

Definition of a mixture. N/A

Specification reference: 4.1.1.3

Scientific models of the atom

Specification reference: C4a

Both specifications refer to developmental stages in the model of atomic

structure as an example of the development of a scientific theory.

N/A Reference to Dalton and Tomson.


4.1.1.4 Relative electrical charges of

subatomic particles


Atomic Structure: C4a (also refers

to masses of subatomic particles).


4.1.1.5 Size and mass of atoms


Fundamental concepts: C4 and C4a

Both specifications give the relative masses of the fundamental particles.

Calculation of the number of protons, neutrons and electrons in a charged

particle is Higher Tier only in the OCR specification, but for students of all

abilities in the AQA specification.


4.1.1.6 Electronic structure


The content of both specifications is the same.

4.1 2 The periodic table



4.1.2.1 The periodic table


C4a

C4c

C4d

The content is similar, although patterns and their explanation are

separated into description of respective groups in the OCR specification.

Prediction of possible reactivity

from the position in the periodic

table.

N/A


4.1.2.2. The development of the

periodic table

Specification reference: C4c

Both specifications consider the contribution of Mendeleev and earlier

contributors. OCR specification includes the ideas of Döbereiner and

Newlands.

OCR Higher Tier: confirmation of Mendeleev's structure through discovery

of unknown elements and investigation into atomic structure.

Knowledge of isotopes, explaining

why the order based on atomic

weights is not always correct.

N/A


4.1.2.3 Metals and non-metals


C2c

C4b to g

There is no equivalent summary topic in the OCR specification, however:

Explanation of the formation of positive and negative ions by metals

and non-metals is included in the sections on bonding (C4b, C4c).

Description of locations in the periodic table is referred to in topics

on respective groups (C4d, C4e, C4f).

Consideration of metallic properties is in the topic on metals and

alloys (C2c, C4g).

OCR doesn’t cover differences in properties.


4.1.2.4 Group 0

N/A



4.1.2.5 Group 1

Specification reference: C4d

The content is very similar in both specifications:

reactions of the alkali metals with water

trends in reactivity moving down the group.

Comparison of Group 1 metals'

density with water.

Reference to reactions and

associated products of Group 1

metals with non-metals.

Construction of balanced symbol

equations for reactions with water

(both Foundation and Higher Tier).

Flame tests (identical content is

covered in section 4.8.3 of the AQA

specification).


4.1.2.6 Group 7

Specification reference: C4e

The content is very similar. Both specifications include reactions with

metals (alkali metals in the OCR specification) and displacement reactions

leading to the pattern in reactivity down the group.

OCR Higher Tier: recall the formulae of bromides and iodides.

AQA specification requires students of all abilities to know the formulae of

the halide ions.

The ionic or molecular nature of the

products formed with metals and

non-metals.

Recall of some uses of Group 7

elements.

Colours and physical states of the

halogens at room temperature.

4.1 3 Properties of transition elements



4.1.3.1 Comparison with Group 1

elements

Specification reference: C4f


4.1.3.2 Typical properties


The OCR specification has more detail, it includes identification based on

position in the periodic table and physical properties with specific


examples of colour and examples of uses as catalysts.

N/A Description of thermal

decomposition reactions of

transition metal carbonates with

word equations (Foundation Tier).

Higher Tier: balanced symbol

equations.

Bonding, structure and the properties of matter

4.2.1 Chemical bonds, ionic, covalent and metallic



4.2.1.1 Chemical bonds


C4b to c

C4g

There is no equivalent summary-section in the OCR specification.

However, OCR covers all the points in topics for each type of bonding.


4.2.1.2 Ionic bonding

Specification reference: C4b

The content is very similar in both specifications: formation and transfer

of ions to form compounds.

Dot and cross diagrams to represent ionic bonding are required by

students of all abilities in the AQA specification while this is Higher Tier

only in the OCR specification.

AQA specification requires working

out the charge on ions from Groups

1, 2, 6 and 7.

OCR requires deducting the

formula for an ionic compound

from the formula of the positive

and negative ions.


4.2.1.3 Ionic compounds


Both specifications include a description of giant ionic structures.

Recognition of a giant ionic

structure from a diagram or model.

Deduction of the empirical formula

from the model and a description of

Knowledge of sodium chloride and

magnesium oxide structures,

comparison of their physical

properties.


its limitations in representing a

giant structure.

Reference to sodium chloride.

Higher Tier: explanation of

differences in these properties

(structure, bonding and prediction

of the properties of other

substances with similar structure).


4.2.1.4 Covalent bonding


C4c and C3h

Description of covalent bonding: shared electrons with reference made

to small molecules, polymers and giant covalent structures.

Dot and cross diagrams are

required for 8 specific molecules at

both Higher and Foundation Tiers.

Deduction of molecular formula

from a given model or diagram and

a description of the model's

limitations.

Carbon dioxide and water as small

covalent molecules; description of

their physical properties.

Higher Tier:

explanation of these

properties in terms of

structure and bonding

dot and cross diagrams.


4.2.1.5 Metallic bonding


C5.4.25

The content is similar, but is Higher Tier only in the OCR specification,

unlike in the AQA specification.

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



4.2.2.1 The three states of matter

This topic is not covered in the

OCR specification although an

understanding of most of the

ideas is assumed, eg in C1g,

Smells, and C1h, Paints and

Pigments.


4.2.2.2 State symbols

Specification reference: C5h


The content is the same, but in the OCR specification recall of state

symbols is for students of all abilities and writing balanced equations,

including state symbols, is Higher Tier only. Both are for students of all

abilities in the AQA specification.


4.2.2.3 Properties of ionic

compounds


Description of the structure of ionic compounds is similar in both

specifications.

Knowledge of sodium chloride only. Knowledge of both sodium

chloride and magnesium oxide.


4.2.2.4 Properties of small

molecules


C1a, C1e and C4c

The content of both specifications is almost the same.

The knowledge that intermolecular forces increase with size of

molecules and the effect on boiling point is included in the OCR

specification in the hydrocarbons context.


4.2.2.5 Polymers


C1d, C1e and C4b

The content of both specifications is very similar: awareness of a

polymer's structure and the effect of intermolecular forces on melting

point.

N/A The effect of intermolecular forces

on strength, stiffness and

hardness of a polymer.


4.2.2.6 Giant covalent structures


Understanding of giant covalent structure is similar in both

specifications.

The OCR topic is covered in the context of allotropes of carbon.

Explanation of structure and bonding properties is required at Higher

Tier only.

Examples of diamond, graphite and

silica.

Examples of diamond and

graphite only.



4.2.2.7 Properties of metals and

alloys


C2c and C4g

The description of metal structures and properties is similar in both

specifications.

A detailed explanation for the

difference in properties between an

alloy and its compositional metals.

Recollection of the main metals in

amalgam, brass and solder with

examples of use.

Limited to recognition of the

differences only.

Higher Tier: detailed description

of metallic bonding and its effect

on properties.


4.2.2.8 Metals as conductors

Specification reference: C4g

Both specifications cover electrical conductivity.

OCR Higher Tier: explanation of electrical conductivity.

Thermal and electrical conductivity. N/A

4.2.3 Structure and bonding of carbon



4.2.3.1 Diamond


The content is almost identical in both specifications.

OCR specification also includes solubility as a property.


4.2.3.2 Graphite


The content is similar in both specifications.

AQA specification describes the bonding of graphite in detail.


4.2.3.3 Graphene and fullerenes



Detailed explanation of the

structure of graphene, fullerenes

and carbon nanotubes.

OCR specification doesn’t refer to

graphene.

Detailed structure of fullerenes is

not required, although an

explanation of the structure of

nanotubes is required at Higher

Tier.

4.2.4 Bulk and surface properties of matter including nanoparticles



4.2.4.1 Sizes of particles and their

properties


Both specifications consider the relative size of nanoparticles and the

effect on their properties.

A mathematical consideration of

surface area to volume ratio.

N/A


4.2.4.2 Uses of nanoparticles


The applications of nanoparticles are different in the two specifications.

Quantitative chemistry

4.3.1 Conservation of mass and the quantitative interpretation of chemical

equations



4.3.1.1 Conservation of mass and

balanced chemical equations


C1 to 6 Fundamental

Chemical Concepts

C3d

C5a

The OCR specification covers balanced chemical equations as a

fundamental concept respective to each section of the specification.

Detailed conservation of mass and how this quantitatively relates to


balanced equations is found in section C3d and C5a.


4.3.1.2 Relative formula mass


C1 to 6 - Fundamental

Chemical Concepts

C3d

C5a

In the OCR specification construction of balanced chemical equations is

referred to as a fundamental concept prior to each respective section.

The use of formula mass to construct equations and perform

quantitative calculations is found in section C3d and C5a.


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



4.3.2.1 Moles (Higher Tier only)


C5a and C5b

This content is similar in both specifications.

Avogadro constant. N/A


4.3.2.2 Amounts of substances in

equations


C5a and C5b

Both specifications require the calculation of masses and products from

balanced equations (Higher Tier only).

Mathematical skills: substitution,

rearranging equations, standard

form and mathematical symbols.

N/A


4.3.2.3 Using moles to balance

equations (Higher Tier only)

This topic is not covered in the

OCR specification. Although

similar knowledge and skills are

used in C5a and C5b.



4.3.2.4 Limiting reactants (Higher

Tier only)


This concept is addressed in the

context of reaction rates.


4.3.2.5 Concentration of solutions


The procedure for making up a

standard solution for students of

all abilities.

Both specifications consider concentration in g/dm3 and require

calculations involving mass, concentration and volume of solution

(Higher Tier only).

4.3.3 Yield and atom economy of chemical reactions



4.3.3.1 Percentage yield


C2e

C3e

C6d

Both specifications require the calculation of percentage yield given

actual and theoretical yield for students of all abilities. They also require

calculating the theoretical amount of a product form a balanced

equation (Higher Tier only in the OCR specification).

Reasons for the actual yield being

less than the theoretical yield.

The concept is referred to in

evaluation of different processes

in C2e and C6d.


4.3.3.2 Atom economy


Content is similar in both specifications. Calculation of atom economy is

for students of all abilities.

In the OCR specification explanation of industrial ramifications is Higher

Tier only.

4.3.4 Using concentrations of solutions in mol/dm3



4.3.4 Using concentrations of

solutions in mol/dm3


C5c

C5d

Concentrations, titrations and titration calculations are addressed

similarly in both specifications.

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



4.3.5 Use of amount of substance in

relation to volumes of gases


This content is similar in both specifications.

However, the OCR specification focuses on measurement of gases and

limiting reactants for students of all abilities.

Higher Tier: calculations involving amounts and volumes of gas (both

specifications).

Chemical changes

4.4.1 Reactivity of metals



4.4.1.1 Metal oxides


C2d

C4d

C6c

Oxidation and reduction are defined in terms of gain and loss of oxygen

in both specifications. The OCR specification focuses on rusting. There is

reference to the oxidation of metals in C2d and C4d.


4.4.1.2 The reactivity series


C6c

C4d


The AQA specification covers reactivity in detail; it refers to an element's

tendency to form positive ions denoting its position in the reactivity

series.

OCR specification covers the reactivity of Group 1 metals in section C4d.

A series of 8 metals with a

prediction of their displacement

reactions.

The OCR specification refers to a

series of 4 metals with a

prediction of their displacement

reactions.


4.4.1.3 Extraction of metals and

reduction


C2c

C6c

Both specifications cover extraction of metals by carbon reduction. They

also require evaluation of specific metal extraction processes.

Unreactive metals such as gold. Focus on copper extraction.


4.4.1.4 Oxidation and reduction in

terms of electrons


C2c

C6c

Higher Tier content including ionic equations (both specifications).

4.4.2 Reactions of acids



4.4.2.1 Reactions of acids with

metals

No equivalent in the OCR

specification.

However, metal/acid redox

reactions are used in sections

C3a, C3b and C3c in studying rate

of reaction. Metal displacement

reactions are referred to in

section C6c.


4.4.2.2 Neutralisation of acids and

salt production




definition of alkalis (however, only AQA defines a base)

production of salts from acids with metal oxides, hydroxides or

carbonates

deduction of the name and formula of the salt formed (deduction

of a formula is at Higher Tier only in OCR).


4.4.2.3 Soluble salts


C4h

C5h

Both specifications cover production, purification and drying of a soluble

salt.

The process is limited to the use of

an insoluble starting material.

There is a required practical to

make a salt from an insoluble oxide

or carbonate.

Preparation of an insoluble salt is

a suggested activity in section

C4h. Students are required to

recall stages in the preparation of

a dry sample in section C5h.


4.4.2 4 The pH scale and

neutralisation


C2f

C5d

The content is similar in both specifications:

ionic equation for neutralisation

litmus paper, universal indicator and pH probes

acid-alkali titrations, although there are some differences in the

treatment of these.

Ionic equations for neutralisation

reactions are required by students

of all abilities (Higher Tier only in

the OCR specification).

A required practical for students of

all abilities.

Higher Tier: calculate the

concentration of one of the

solutions, either in g/dm3 or

mol/dm3.

Higher Tier: perform calculations

involving concentration, mass,

volume and balanced equations,

although students of all abilities

may be given a formula in which

to substitute results.

All students are expected to recall

how to make up a standard

solution and to estimate the

uncertainty in the results.



4.4.2.5 Strong and weak acids


Both specifications give examples of acids, although the lists are not the

same. Both describe strong and weak acids in terms of pH.

The entire topic is at Higher Tier only in the AQA specification.

Description of extent of ionisation

and the mathematical link between

pH and hydrogen ion concentration.

N/A

4.4.3 Electrolysis



4.4.3.1 The process of electrolysis


The content of both specifications is very similar.

Throughout the electrolysis topic,

Higher Tier students are expected

to write and balance half-equations

for reactions at the electrodes.

N/A


4.4.3.2 Electrolysis of molten ionic

compounds


Common content in both specifications:

lead bromide as an example

production of metals at the negative electrode and non-metals at

the positive electrode

half equations are required at Higher Tier.

The terms anode and cathode. N/A


4.4.3.3 Using electrolysis to extract

metals


The AQA example: aluminium.

The OCR example: extraction of copper.


N/A Higher Tier: gain or loss of

electrons at the electrodes.


4.4.3.4 Electrolysis of aqueous

solutions


Content is similar in both specifications. OCR focuses on brine and

sulphuric acid.

There is a required practical

investigating the electrolysis of

aqueous solutions using inert

electrodes.

Students of all abilities:

knowledge of the products at both

electrodes.

Higher Tier: half equations (both

tiers in AQA).


4.4.3.5 Representation of reactions

at electrodes as half equations

N/A

Energy changes

4.5.1 Exothermic and endothermic reactions



4.5.1.1 Energy transfer during

exothermic and endothermic

reactions


Both specifications require an understanding of the terms exothermic

and endothermic. AQA specification is more detailed.

Examples of exothermic and

endothermic changes.

The link between energy change

and temperature change.

Everyday uses of exothermic and

endothermic reactions.


investigating the factors affecting

temperature changes in a list of

N/A


possible reaction mixtures.

Specification reference: 4.5.1.2

Reaction profiles


The OCR specification refers to energy level diagrams rather than energy

profiles. Both include activation energy. This is Higher Tier only in the

OCR specification.


4.5.1.3 The energy change of

reactions


Content common in both specifications:

energy needed to break bonds and energy released on forming

bonds (for students of all abilities in OCR, Higher Tier in AQA)

calculation of the overall energy change from bond energy data

(Higher Tier only).

4.5.2 Chemical cells and fuel cells



4.5.2.1 Cells and batteries

N/A


4.5.2.2 Fuel cells



overall reaction (Higher and Foundation Tier)

half equations (Higher Tier only).

The rate and extent of chemical change

4.6.1 Rate of reaction



4.6.6.1 Calculating rates of

reactions


The OCR specification requires students to explain meaning of a


chemical reaction rate, including the use of appropriate units and

interpretation of data.

The AQA specification is more detailed and requires further calculation.

Rate of reaction is defined

mathematically for students of all

abilities, using units of g/s or

cm3/s.

Higher Tier: using units involving

moles.

All students are required to draw

and interpret graphs, including

drawing tangents to the curve and

using the slope as a measure of

rate.

Higher Tier: calculating the

gradient of a tangent to the curve.

N/A


4.6.1.2 Factors which affect the

rates of chemical reactions


Both specifications include the effect of size of solid particles,

concentration of solutions, temperature and the presence of a catalyst.

Both require knowledge of how rate can be followed by collecting a gas,

weighing the mixture and formation of a precipitate or colour.

The effect of gas pressure.

Students are required to explain

the effect of size of pieces of solid

in terms of surface area to volume

ratio.


investigating how concentration

changes affect the rate of a

reaction.

Students are required to interpret

information about the control of

rates of reaction in chemical

synthesis.


4.6.1.3 Collision theory and

activation energy


C3b

C3c

Both specifications use collision frequency to explain how rate depends

on the concentration of a solution, but there are significant differences

in the rest of the topic.


Surface area to volume ratio is

required to explain the effect of

changing the size of pieces of a

solid.

Energy of collisions and activation

energy is required to explain the

effect of temperature changes.

The effect of pressure changes is

also explained by collision

frequency.

The effect of changing the size of

pieces of a solid is explained in

terms of collision frequency.

The effect of temperature changes

is not covered.


4.6.1.4 Factors that increase the

rate of reaction


C3b

C3c

Both specifications cover the effect of changing the concentration of a

solution and the size of pieces of solid in terms of collision frequency.

The effect of pressure and

temperature changes. The effect

of temperature changes on the

energy of collision.

Students are expected to predict

and explain the effect of changing

conditions and to use simple ideas

about proportionality when using

collision theory.

N/A


4.6.1.5 Catalysts


Both specifications define a catalyst. AQA specification explains it

provides an alternative route of lower activation energy.

Reaction profiles. N/A

4.6.2 Reversible reactions and dynamic equilibrium



4.6.2.1 Reversible reactions



The content is similar in both specifications. However, in the ammonium

chloride dissociation example the AQA specification refers to changing

the conditions to change the direction.


4.6.2.2 Energy changes and

reversible reactions

This topic is not covered in the OCR

specification. However, it may be

implicit in the effect of temperature

change on equilibrium (C5f).


4.6.2.3 Equilibrium


Both specifications refer to a reversible reaction reaching equilibrium.

OCR Higher Tier: dynamic equilibrium, the contact process and

explanation of its conditions.


4.6.2.4 The effect of changing

conditions on equilibrium (Higher

Tier only)


Le Chatelier's principle. N/A


4.6.2.5 The effect of changing

concentration (Higher Tier only)



4.6.2.6 The effect of temperature

changes on equilibrium


Full explanation of this topic is at Higher Tier only for both specifications.

The AQA specification goes into more detail, students are required to

predict the effect of a change in temperature on given reactions at

equilibrium, in terms of their endothermic/exothermic character.


4.6.2.7 The effect of pressure

changes on equilibrium


The OCR specification requires description by students of all abilities and

explanation at Higher Tier.

Higher Tier only in the AQA specification. Students are required to

predict the effect of a change in pressure on given reactions at

equilibrium, in terms of the number of molecules on each side of the


balanced equation.

Organic chemistry

4.7.1 Carbon compounds as fuels and feedstock



4.7.1.1 Crude oil, hydrocarbons

and alkanes


C1a

C1d

The content is very similar in both specifications.

The origin of crude oil; the general

formula for alkanes.

N/A


4.7.1.2 Fractional distillation and

petrochemicals


The content is very similar in both specifications. AQA emphasises the

ability of carbon atoms to form families of similar compounds with the

consequential vast array of natural and synthetic compounds.

N/A Higher Tier: detailed explanation for

fractions' different boiling points.


4.7.1.3 Properties of

hydrocarbons


C1a

C1b

Both specifications include the effect of molecule size on boiling point.

They also cover the complete combustion of hydrocarbons as oxidation.

The trends of viscosity and

flammability with molecular size,

their influence on the use of

hydrocarbons as fuels.

Students of all abilities are

expected to write balanced

equations for combustion

reactions.

N/A

Specification reference: Specification reference:


4.7.1.4 Cracking and alkenes C1a

C1d

The content is very similar, but OCR splits it across two sections.

Students of all abilities are

required to balance chemical

equations that represent cracking

using formulae of reactants and

products.

N/A

4.7.2 Reactions of alkenes and alcohols



4.7.2.1 Structure and formulae of

alkenes


Nearly all of the content is specific to AQA specification.

The C=C functional group, the

general formula, the structures of

the first four alkenes.

N/A


4.7.2.2 Reactions of alkenes


C1d

C1b

C6d

The synthetic route for conversion of ethane to ethanol via ethene is

covered in section C6d.

Combustion of hydrocarbons is referred to in C1b, alkenes aren’t

mentioned.

Addition reactions and the formation of dibromo compounds is covered

in section C1d.

The reaction of alkenes with

oxygen, hydrogen, water and

halogens.

The displayed formulae for the

first four alkenes.

N/A



4.7.2.3 Alcohols


The content is similar in both specifications:

names, formulae, functional group, structures and uses of

methanol and ethanol

combustion and reaction with sodium (Higher Tier only in OCR).

Propanol and butanol. Fermentation is covered in more

detail, including limits to the

concentration of ethanol produced

in fermentation and concentration

of the solution by distillation.

Comparison and evaluation of

fermentation and hydration as

production methods.


4.7.2.4 Carboxylic acids


C1g

C5g

C6g

The AQA specification is more detailed. The OCR specification refers to

their nature as weak acids (C5g), reaction with alcohols to produce

esters (C1g) and within the context of fats and oils (C6g).

Propanoic, butanoic and acids;

their structural formulae.

In item C1g the OCR specification

covers the properties and uses of

esters and a detailed method for

their preparation.

N/A Perfumes and animal testing of

cosmetics are covered in detail in

section C1g.

N/A Saponification using sodium

hydroxide is covered in section C6g

(both for Foundation and Higher

Tiers).

4.7.3 Synthetic and naturally occurring polymers



4.7.3.1 Addition polymerisation


Both specifications cover polymerisation as the joining of many

monomers to form long chains.

OCR Higher Tier: drawing the displayed formula of an addition polymer.

Poly(ethene) and poly(propene). N/A


4.7.3.2 Condensation

polymerisation

N/A


4.7.3.3 Amino acids


specification. However, proteins and

denaturation are mentioned in

cooking context (C1f).


4.7.3.4 DNA and other naturally

occurring polymers

N/A

N/A Nylon and Gore-Tex as examples of

designer polymers (C1e).

Chemical analysis

4.8.1 Purity, formulations and chromatography



4.8.1.1 Pure substances


Both specifications cover identification of pure substances based on

comparison of physical properties with less pure counterparts.

Definition of purity. N/A


4.8.1.2 Formulations


specification.

However, fuels, paints, alloys,

fertilisers and foods are referred to

in sections C1b, C3f and C6b (fuels),


C1h (paints), C2c and C2d (alloys),

C2g (fertilisers) and C1f (foods).

N/A The OCR specification details not

present in the AQA specification:

C1h - Paints and Pigments

C1f - Emulsifiers

C6g - Natural Fats and Oils

C6h - Detergents


4.8.1.3 Chromatography


C3g

C6h

The AQA specification is more detailed.

The OCR specification only refers to chromatography in terms of

extraction of chemicals from plants and elucidating the purity of a

substance through thin layer chromatography.

Solvents are discussed in other areas of the OCR specification without

reference to chromatography, eg in C1g, Smells and C1h, Paints and

Pigments


investigating the chromatography

of coloured substances and

calculation of Rf values.

N/A

4.8.2 Identification of common gases



4.8.2.1 Test for hydrogen




4.8.2.2 Test for oxygen





4.8.2.3 Test for carbon dioxide


Definition of limewater as an

aqueous solution of calcium

hydroxide.

N/A


4.8.2.4 Test for chlorine



4.8.3 Identification of ions by chemical and spectroscopic means



4.8.3.1 Flame tests


Both specifications require knowledge of flame tests and recollection of

flame colours for lithium, sodium and potassium.

Content includes flame colours for

calcium and copper.

N/A


4.8.3.2 Metal hydroxides


Both specifications cover the precipitation of metal hydroxides as an

identification method for metal ions, although the list of ions is slightly

different.

N/A An understanding of precipitation in

the context of formation of an

insoluble compound.

Higher Tier: ionic equations for

precipitation reactions.


4.8.3.3 Carbonates

N/A

Reactions of carbonates in terms of thermal decomposition and

reactions with acids are covered in several areas of the OCR

specification. Solubility in water is only mentioned in terms of water

hardness and calcium carbonate.


The pattern of solubility of

carbonates.

N/A


4.8.3.4 Halides




4.8.3.5 Sulfates




4.8.3.6 Instrumental methods

N/A

General advantages of

instrumental methods.

N/A


4.8.3.7 Flame emission

spectroscopy

N/A

Students are expected to interpret

a spectrum, given appropriate

data.

N/A

There is a required practical to

identify the ions in a single ionic

compound using the test tube

reactions.

N/A

Chemistry of the atmosphere

4.9.1 The composition and evolution of the Earth's atmosphere



4.9.1.1 The proportions of

different gases in the atmosphere




4.9.1.2 The Earth's early


C1.1.5 to 6


atmosphere C.1.1.8

The content of both specifications is almost the same.

A consideration of how theories

about the early atmosphere have

changed; limitations of the

evidence.

The presence of nitrogen,

methane and ammonia.

Higher Tier: detailed description of

atmospheric evolution.


4.9.1.3 How oxygen increased



The chemical equation for

photosynthesis.

N/A


4.9.1.4 How carbon dioxide

decreased


The content is similar, but the AQA specification goes into more detail

about the formation of limestone, coal and crude oil.

4.9.2 Carbon dioxide and methane as greenhouse gases



4.9.2.1 Greenhouse gases

The mechanism of the greenhouse

effect in terms of radiation of

different wavelengths is not

covered in the OCR specification.


4.9.2.2 Human activities which

contribute to an increase of

greenhouse gases in the

atmosphere

The increase of carbon dioxide and

methane in the atmosphere is not

covered in the OCR specification

except for a brief mention of carbon

dioxide as a greenhouse gas in C1b.


4.9.2.3 Global climate change

The potential effects of climate

change are not covered in the OCR

specification.



4.9.2.4 The carbon footprint and

its reduction

N/A

N/A Specification reference: C6e:

The OCR specification covers CFCs

and the depletion of the ozone layer

in detail.

4.9.3 Common atmospheric pollutants and their sources



4.9.3.1 Atmospheric pollutants

from fuels


C1b

C1c


the formation of carbon dioxide, carbon monoxide, carbon, sulfur

dioxide and oxides of nitrogen

particulates.


4.9.3.2 Properties and effects of

atmospheric pollutants


C1b

C1c

Much of the content is the same:

carbon monoxide's effect on the blood

sulfur dioxide and oxides of nitrogen causing acid rain.

The effect of particulates on

global dimming. The respiratory

effects of particulates, sulfur

dioxide and oxides of nitrogen.

N/A

Using resources

4.10.1 Using the Earth's resources and obtaining potable water



4.10.1.1 Using the Earth's

resources and sustainable

development

Not covered in the OCR

specification. However, ideas

regarding the use of chemistry to

improve processes can be found in

section C3e, Percentage Yield and

Atom Economy and C3g, Batch or

Continuous.

Similar ideas are covered in both specifications; both refer to natural

and synthetic materials, but use different examples.

The AQA specification refers to finite and renewable resources and to

sustainable development.

The OCR specification focuses on the properties of materials;

sustainability is developed in other areas throughout the specification.

N/A Specification reference: C2a

Earth's geology is covered in detail.

N/A The use of limestone as a building

material, including the production

of cement and concrete (C2b).

N/A The acquisition of salt and the

chlor-alkali industry are covered in

detail in C2h.

N/A Specification reference: C3a

The development of pharmaceutical

drugs and batch and continuous

production processes are covered in

detail.


4.10.1.2 Potable water



N/A Specification reference: C6f

Water hardness and its removal are

covered in detail.

Specification reference: N/A


4.10.1.3 Waste water treatment


4.10.1.4 Alternative methods of

extracting metals

Phytomining and bioleaching is not

covered in the OCR specification,

except for copper extraction

mentioned in C2c.

4.10.2 Life cycle assessment and recycling



4.10.2.1 Life cycle assessment

There is no reference to this

content in the OCR specification

although consideration is given to

the environmental impact of a

variety of chemical products,

particularly polymers, in C1e.


4.10.2.2 Ways of reducing the use

of resources


C1e

C2c to 2d

Both specifications cover recycling of metals and environmental impacts

of extracting metals. However, OCR specification does not consider other

materials. Recycling polymers is also considered at Higher Tier in the

OCR item C1e.

Reduction in use of materials and

reuse (for example of glass

bottles); recycling.

Resources also include glass,

building materials and ceramics.

The energy required coming from

limited resources.

N/A

4.10.3 Using materials



4.10.3.1 Corrosion and its

prevention


C2d

C6c


N/A Higher Tier: the disadvantages of

using tin plate for protection

against rusting.


4.10.3.2 Alloys as useful materials


The content is very similar in both specifications, however they use

different examples.

AQA specification goes into more detail, eg the carat system for alloys of

gold.

Bronze, steel, gold alloys and

aluminium alloys.

Amalgam, brass and solder.


4.10.3.3 Ceramics, polymers and

composites


The AQA specification goes into more detail and provides more

examples.

Glass, ceramics, composites and

polymers.

The specification includes the

properties of polymers depending

on the monomer used and the

conditions under which they are

made, using LDPE and HDPE as

examples. Polymers are classified

as thermo softening or

thermosetting.

Glass's relationship with sand and

brick's with clay.

There is no mention of low or high

density poly(ethene) or thermo

softening or thermosetting

polymers.

4.10.4 The Haber process and the use of NPK fertilisers



4.10.4.1 The Haber process


The content is very similar in both specifications. The principles of

dynamic equilibrium are at Higher Tier in the AQA specification, but only

a simple explanation of the effect of changing temperature and pressure

is required at the same tier by OCR. The relationship between

commercially used conditions and cost/availability is referred to by both


specifications.

The removal of ammonia from the

reaction mixture by cooling.

A balanced symbol equation is used

at both tiers (although partly given

at foundation tier).


4.10.4.2 Production and uses of

NPK fertilisers

Although the use of fertilisers is

covered in C2g, there is no

reference to the production of NPK

fertilisers.

N/A Eutrophication is covered in detail

in C2g.

gcse chemistry from ocr b switching to aqa

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