AQA GCSE COMBINED SCIENCE TRILOGY CHEMISTRY

ALL MY GCSE CHEMISTRY REVISION NOTES

Revision summary help for the 9-1 AQA GCSE Combined Science Trilogy 1st chemistry paper - learning objectives

AQA GCSE Grade 9-1 Combined Science Trilogy chemistry 8464 Paper 1 Chemistry 1 1F 1H papers - Combined Science chemistry paper 1 Topic 8 "Atomic structure and the periodic table", Topic 9 "Bonding, structure and the properties of matter", Topic 10 "Quantitative chemistry", Topic 11 "Chemical changes", Topic 12 "Energy changes"

LINK for AQA GCSE Combined Science Trilogy chemistry paper 2

LINK for AQA 9-1 GCSE CHEMISTRY 1 paper 1

LINK for AQA 9-1 GCSE CHEMISTRY 2 paper 2

 For ALL other exam papers, use and bookmark the link below

INDEX for all links * PAST PAPERS

PLEASE READ CAREFULLY THE FOLLOWING POINTS before using my AQA 9-1 GCSE science pages

  1. ALL my unofficial GCSE (Grade 9-1) revision help summaries are based on the NEW 2016 official AQA (Grade 9-1) GCSE CHEMISTRY/combined science trilogy chemistry specifications.

  2. Make sure you know whether you are doing separate science AQA GCSE grade 9-1 CHEMISTRY OR AQA GCSE grade 9-1 Combined Science Trilogy chemistry.

  3. Also, make sure you know whether you are entered for a higher tier (HT) or a foundation tier (FT) AQA GCSE science-chemistry course, so watch out for the (HT only) 'markers'.

  4. I hope my revision pages help as you get to know my website, its very big and not always easy to navigate, but it is no substitute for making good lesson notes, trying your best on homework questions, studying your textbook, doing past papers of AQA GCSE combined science/chemistry for exam question practice and, above all, attentive to your teacher's teaching!

  5. I know from feedback that my gcse science summary revision pages have proved useful but they do not guarantee a high grade, that all depends on you and the factors mentioned in point 4. above. Please note that my GCSE science revision pages are designed to be used for online convenience, so, beware, printouts could be quite long!
  6. AQA GCSE grade 9-1 combined science trilogy chemistry 1 PAST PAPERS and specimen practice paper questions

  7. 'Doc b's chemistry' is a big website so the Google [SEARCH] box at the bottom of each index or revision notes page can be VERY USEFUL - sometimes its better than the indexes for finding things!

  8. Links to specific GCSE chemistry notes and quizzes about the topic in question have been added, and from these pages, you may find other links to more useful material linked to the topic.



Syllabus-specification CONTENT INDEX of revision summary notes

Revision summaries for AQA 9-1 GCSE Combined Science: Trilogy Chemistry Paper 1 (this page)

What's assessed in this paper?    (the 'sub-topic' numbers are just based on a simple numerical order)

SUMMARY Topic 8 Atomic structure and the periodic table  (AQA Comb. Sci. Trilogy Chemistry paper 1)

Topic 1.1 A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes
Topic 1.2 The periodic table
 

SUMMARY Topic 9 Bonding, structure, and the properties of matter  (AQA Comb. Sci. Trilogy Chem. paper 1)

Topic 2.1 Chemical bonds, ionic, covalent and metallic
Topic 2.2 How bonding and structure are related to the properties of substances
Topic 2.3 Structure and bonding of carbon
 

SUMMARY Topic 10 Quantitative chemistry  (AQA GCSE Combined Science Trilogy Chemistry paper 1)

Topic 3.1 Conservation of mass and the quantitative interpretation of chemical equations
Topic 3.2 Use of amount of substance in relation to masses of pure substances
 

SUMMARY Topic 11 Chemical changes  (AQA GCSE 9-1 Combined Science Trilogy Chemistry paper 1)

Topic 4.1 Reactivity of metals
Topic 4.2 Reactions of acids
Topic 4.3 Electrolysis

SUMMARY Topic 12 Energy changes  (Combined Science Trilogy Chemistry paper 1)

Topic 5.1 Exothermic and endothermic reactions
 


Revision summaries for AQA 9-1 GCSE Combined Science: Trilogy Chemistry Paper 2 (separate page)

What's assessed in this paper?

SUMMARY Topic 13 The rate and extent of chemical change (AQA Comb. Sci. Trilogy Chemistry paper 2)

SUMMARY Topic 14 Organic chemistry  (AQA GCSE Combined Science Trilogy Chemistry paper 2)

SUMMARY Topic 15 Chemical analysis  (AQA GCSE Combined Science Trilogy Chemistry paper 2)

SUMMARY Topic 16 Chemistry of the atmosphere (AQA GCSE Combined Science Trilogy Chemistry paper 2)

SUMMARY Topic 17 Using resources  (AQA GCSE Combined Science Trilogy Chemistry paper 2)



SUBJECT CONTENT of the syllabus-specification:

TOPICS for AQA GCSE Combined Science Trilogy Chemistry Paper 1


Topic 8 Atomic structure and the periodic table

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 8 "Atomic structure and the periodic table")

Know the periodic table provides chemists with a structured organisation of the known chemical elements from which they can make sense of their physical and chemical properties. The historical development of the periodic table and models of atomic structure provide good examples of how scientific ideas and explanations develop over time as new evidence emerges. The arrangement of elements in the modern periodic table can be explained in terms of atomic structure which provides evidence for the model of a nuclear atom with electrons in energy levels.

AQA GCSE (Grade 9-1) Combined Science Topic 8 Atomic structure and the periodic table quiz content: elements, compounds, separating mixtures, equations, atomic structure, relative atomic mass, periodic table, group 0 noble gases, group 1 alkali metals, group 7 halogens, transition metals

Topic 8 Atomic structure and the periodic table QUIZ (AQA GCSE science-chemistry)

HT = higher tier (harder - usually more theory & depth) and FT = foundation tier (easier)  1st drafts of AQA quizzes



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

1.1.1 Atoms, elements and compounds

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 8 "Atomic structure and the periodic table")

Know that all substances are made of atoms. An atom is the smallest part of an element that can exist. Atoms of each element are represented by a chemical symbol, eg O represents an atom of oxygen, Na represents an atom of sodium. There are about 100 different elements. Elements are shown in the periodic table. Compounds are formed from elements by chemical reactions. Compounds contain two or more elements chemically combined in fixed proportions and can be represented by formulae using the symbols of the atoms from which they were formed. Compounds can only be separated into elements by chemical reactions. Chemical reactions can be represented by word equations or equations using symbols and formulae. You will be supplied with a periodic table for the exam and you should be able to:

Be able to use the names and symbols of the first 20 elements in the periodic table, the elements in Groups 1 and 7, and other elements in this specification

Be able to name compounds of these elements from given formulae or symbol equations

Be able to write word equations for the reactions mentioned.

Be able to write formulae and balanced chemical equations for the reactions mentioned.

(HT only) Be able to write balanced half equations and ionic equations where appropriate and indicated.

Definitions in Chemistry eg atom, molecule, formula, element, compound, mixture etc.

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

Multiple Choice Quiz on balancing Symbol Chemical Equations with numbers

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

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

1.1.2 Mixtures

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 8 "Atomic structure and the periodic table")

A mixture consists of two or more elements or compounds not chemically combined together. The chemical properties of each substance in the mixture are unchanged. Mixtures can be separated by physical processes such as filtration, crystallisation, simple distillation, fractional distillation and chromatography. These physical processes do not involve chemical reactions. You should be able to:

Be able to describe, explain and give examples of the specified processes of separation

Be able to suggest suitable separation and purification techniques for mixtures when given appropriate information.

You should have experienced the safe use of a range of equipment to separate chemical mixtures.

Methods of Separating Mixtures of substances

Distillation - Simple and Fractional Distillation 

Paper & thin layer chromatography (tlc) and gas chromatography (gc, glc)

Filtration, evaporation, crystallisation, drying and decantation

1.1.3 Scientific models of the atom

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 8 "Atomic structure and the periodic table")

Appreciate that new experimental evidence may lead to a scientific model being changed or replaced. Before the discovery of the electron atoms were thought to be tiny spheres that could not be divided. The discovery of the electron led to the plum pudding model of the atom. The plum pudding model suggested that the atom was a ball of positive charge with negative electrons embedded in it. The results from the Rutherford and Marsden’s alpha scattering experiments led to the plum pudding model being replaced by the nuclear model. Niels Bohr adapted the nuclear model by suggesting that electrons orbit the nucleus at specific distances. The theoretical calculations of Bohr agreed with experimental observations. Later experiments led to the idea that the positive charge of any nucleus could be subdivided into a whole number of smaller particles, each particle having the same amount of positive charge. The name proton was given to these particles. In 1932 the experimental work of James Chadwick provided the evidence to show the existence of neutrons within the nucleus. This historical context provides an opportunity for you to show an understanding of why and describe how scientific methods and theories develop over time.

You should be able to:

Be able to describe why the new evidence from the scattering experiment led to a change in the atomic model. Details of these experiments are not required.

Be able to describe the difference between the plum pudding model of the atom and the nuclear model of the atom.

Details of experimental work supporting the Bohr model are not required.

Details of Chadwick’s experimental work are not required.

Atomic Structure - detailed notes

1.1.4 Relative electrical charges of subatomic particles

Know the relative electrical charges of the particles in atoms: proton, neutron and electron. In an atom, the number of electrons is equal to the number of protons in the nucleus. Atoms have no overall electrical charge. The number of protons in an atom of an element is its atomic number. All atoms of a particular element have the same number of protons. Atoms of different elements have different numbers of protons. You should be able to use the atomic model to describe atoms.

Atomic Structure - detailed notes

1.1.5 Size and mass of atoms (common content with physics)

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 8 "Atomic structure and the periodic table")

Appreciate that atoms are extremely small, having a radius of about 0.1 nm (1 x 10-10 m). The radius of a nucleus is less than 1/10 000 of that of the atom (about 1 x 10-14 m). Almost all of the mass of an atom is in the nucleus. You must know the relative masses of protons, neutrons and electrons. The sum of the protons and neutrons in an atom is its mass number. Atoms of the same element can have different numbers of neutrons; these atoms are called isotopes of that element. Atoms can be represented as shown symbolically e.g. or (upper left = mass number, lower left = atomic number).

You should be able to calculate the numbers of protons, neutrons and electrons in an atom or ion, given its atomic number and mass number.

Be able to use SI units and the prefix nano.

Be able to recognise expressions in standard form.

Be able to estimate the size and scale of atoms.

Atomic Structure including isotopes

Multiple choice quiz on  Atomic structure, isotopes & electronic structure of atoms

Atomic Structure crossword puzzle * Answers

Gap-fill worksheet on Atomic Structure

Matching pair quiz on Atomic and electronic structure 1. fundamental particles

Matching pair quiz on Atomic and electronic structure 2. periodic table

1.1.6 Relative atomic mass

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 8 "Atomic structure and the periodic table")

The relative atomic mass of an element is an average value that takes account of the abundance of the isotopes of the element.

You should be able to calculate the relative atomic mass of an element given the percentage abundance of its isotopes.

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

Relative atomic mass - type in answer QUIZ

Relative atomic mass - multiple choice QUIZ

1.1.7 Electronic structure

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 8 "Atomic structure and the periodic table")

The electrons in an atom occupy the lowest available energy levels (innermost available shells). The electronic structure of an atom can be represented by numbers or by a diagram (on left). For example, the electronic structure of sodium is 2,8,1 or showing two electrons in the lowest energy level, eight in the second energy level and one in the third energy level. You may answer questions in terms of either energy levels or shells.

You should be able to work out and represent the electronic structures of the first twenty elements of the periodic table in both forms.

Atomic Structure - section on electron arrangements

Matching pair quiz on Atomic and electronic structure 1. fundamental particles

Matching pair quiz on Atomic and electronic structure 2. periodic table

Multiple choice quiz on  Atomic structure, isotopes & electronic structure of atoms


1.2 The periodic table

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 8 "Atomic structure and the periodic table")

Topic 8 Atomic structure and the periodic table QUIZ (AQA GCSE science-chemistry)

1.2.1 The periodic table

The elements in the periodic table are arranged in order of atomic (proton) number and so that elements with similar properties are in columns, known as groups. The table is called a periodic table because similar properties occur at regular intervals.

Elements in the same group in the periodic table have the same number of electrons in their outer shell (outer electrons) and this gives them similar chemical properties. You should be able to:

explain how the position of an element in the periodic table is related to the arrangement of electrons in its atoms and hence to its atomic number

predict possible reactions and probable reactivity of elements from their positions in the periodic table.

Periodic Table Notes - an overview (links to separate groups notes)

Multiple choice quiz on the basics of the Periodic Table (better near end of course)

Task sheet worksheet on Periodic Table history * (answers)

Basic Periodic Table Task sheet worksheet * (answers)

Gap-fill worksheet on the Periodic Table

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

1.2.2 Development of the periodic table

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 8 "Atomic structure and the periodic table")

Know that before the discovery of protons, neutrons and electrons, scientists attempted to classify the elements by arranging them in order of their atomic weights.

The early periodic tables were incomplete and some elements were placed in inappropriate groups if the strict order of atomic weights was followed.

Mendeleev overcame some of the problems by leaving gaps for elements that he thought had not been discovered and in some places changed the order based on atomic weights.

Elements with properties predicted by Mendeleev were discovered and filled the gaps. Knowledge of isotopes made it possible to explain why the order based on atomic weights was not always correct.

You should be able to describe these steps in the development of the periodic table and be able to explain how testing a prediction can support or refute a new scientific idea i.e the evolution of the periodic table format.

Periodic Table Notes - an overview - history section

Multiple choice quiz on the basics of the Periodic Table

1.2.3 Metals and non-metals

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 8 "Atomic structure and the periodic table")

Elements that react to form positive ions are metals. Elements that do not form positive ions are nonmetals. The majority of elements are metals. Metals are found to the left and towards the bottom of the periodic table. Non-metals are found towards the right and top of the periodic table.

You should be able to:

explain the differences between metals and non-metals on the basis of their characteristic physical and chemical properties.

explain how the atomic structure of metals and non-metals relates to their position in the periodic table

explain how the reactions of elements are related to the arrangement of electrons in their atoms and hence to their atomic number.

Periodic Table Notes - an overview (including section on metals and non-metals)

Multiple choice quiz on the basics of the Periodic Table

1.2.4 Group 0 Noble Gases

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 8 "Atomic structure and the periodic table")

Know that the elements in Group 0 of the periodic table are called the noble gases. They are unreactive and do not easily form molecules because their atoms have stable arrangements of electrons. The noble gases have eight electrons in their outer energy level, except for helium, which has only two electrons. The boiling points of the noble gases increase with increasing relative atomic mass (going down the group). You should be able to:

explain how properties of the elements in Group 0 depend on the outer shell of electrons of the atoms

predict properties from given trends down the group.

Group 0 Noble Gases

Multiple choice quiz on Group 0 The Noble Gases

Wordfill worksheet on the Noble Gases (answers)

1.2.5 Group 1 Alkali Metals

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 8 "Atomic structure and the periodic table")

Know the elements in Group 1 of the periodic table are known as the alkali metals and have characteristic properties because of the single electron in their outer shell.

You should be able to describe the reactions of the first three alkali metals with oxygen, chlorine and water.

In Group 1, the reactivity of the elements increases going down the group.

You should be able to:

explain how properties of the elements in Group 1 depend on the outer shell of electrons of the atoms

predict properties from given trends down the group.

Group 1 Alkali Metals - physical and chemical properties

Multiple choice quiz on the Group 1 Alkali Metals

Word-fill worksheet on the Group 1 Alkali Metals

1.2.6 Group 7 The halogens

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 8 "Atomic structure and the periodic table")

Know the elements in Group 7 of the periodic table are known as the halogens and have similar reactions because they all have seven electrons in their outer shell. The halogens are non-metals and consist of molecules made of pairs of atoms.

You should be able to describe the nature of the compounds formed when chlorine, bromine and iodine react with metals and non-metals.

In Group 7, the further down the group an element is the higher its relative molecular mass, melting point and boiling point.

In Group 7, the reactivity of the elements decreases going down the group.

A more reactive halogen can displace a less reactive halogen from an aqueous solution of its salt - so you can predict the outcome of particular combinations of group  7 element and the salt of another halogen.

You should be able to:

explain how properties of the elements in Group 7 depend on the outer shell of electrons of the atoms

predict properties from given trends down the group.

Group 7 Halogens - physical and chemical properties

Multiple choice quiz on the Group 7 Halogens

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

Word-fill work sheet on the Halogens

The Halogens (matching pair quiz on their appearance)

Some general periodic table questions

Multiple choice quiz on the basics of the Periodic Table

Task sheet worksheet on Periodic Table history * (answers)

Basic Periodic Table Task sheet worksheet * (answers)

Structured question on the reactivity of elements and the periodic table and answers


Topic 9 Bonding, structure, and the properties of matter

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 9 "Bonding, structure and properties of matter")

Appreciate that chemists use theories of structure and bonding to explain the physical and chemical properties of materials. Analysis of structures shows that atoms can be arranged in a variety of ways, some of which are molecular while others are giant structures. Theories of bonding explain how atoms are held together in these structures. Scientists use this knowledge of structure and bonding to engineer new materials with desirable properties. The properties of these materials may offer new applications in a range of different technologies.

AQA GCSE (Grade 9-1) Chemistry Topic 2 Bonding, structure and properties of matter quiz content: ionic bonding, covalent bonding, metallic bonding, states of matter, need Qs on polymers, graphene, fullerenes, nanotubes, nanoparticles

Topic 9 Bonding, structure and properties of matter QUIZ (AQA GCSE science-chemistry)

HT = higher tier (harder - usually more theory & depth) and FT = foundation tier (easier)  1st drafts of AQA quizzes



2.1 Chemical bonds, ionic, covalent and metallic

2.1.1 Chemical bonds

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 9 "Bonding, structure and properties of matter")

Know there are three types of strong chemical bonds: ionic, covalent and metallic. For ionic bonding the particles are oppositely charged ions. For covalent bonding the particles are atoms which share pairs of electrons. For metallic bonding the particles are atoms which share delocalised electrons.

Ionic bonding occurs in compounds formed from metals combined with non-metals.

Covalent bonding occurs in non-metallic elements and in compounds of non-metals.

Metallic bonding occurs in metallic elements and alloys.

You should be able to explain chemical bonding in terms of electrostatic forces and the transfer or sharing of electrons.

Introduction to Chemical Bonding

Quiz on the Structure, Properties and Chemical Bonding of Materials

(quiz best done after all bonding sections covered)

2.1.2 Ionic bonding

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 9 "Bonding, structure and properties of matter")

Know that when a metal atom reacts with a non-metal atom electrons in the outer shell of the metal atom are transferred. Metal atoms lose electrons to become positively charged ions. Non-metal atoms gain electrons to become negatively charged ions. The ions produced by metals in Groups 1 and 2 and by non-metals in Groups 6 and 7 have the electronic structure of a noble gas (Group 0). The electron transfer during the formation of an ionic compound can be represented by a dot and cross diagrams. You need to be able to visualise and represent 2D and 3D forms including two dimensional representations of 3D objects. You should be able to:

draw dot and cross diagrams for ionic compounds formed by metals in Groups 1 and 2 with non-metals in Groups 6 and 7

The charge on the ions produced by metals in Groups 1 and 2 and by non-metals in Groups 6 and 7 relates to the group number of the element in the periodic table.

You should be able to work out the charge on the ions of metals and non-metals from the group number of the element, limited to the metals in Groups 1 and 2, and non-metals in Groups 6 and 7.

Introduction to Chemical Bonding

Ionic bonding and ionic compounds and their properties

Quiz on the Structure, Properties and Chemical Bonding of Materials

2.1.3 Ionic compounds

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 9 "Bonding, structure and properties of matter")

Know that an ionic compound is a giant structure of ions. Ionic compounds are held together by strong electrostatic forces of attraction between oppositely charged ions. These forces act in all directions in the lattice and this is called ionic bonding. Know the structure of sodium chloride can be represented in the following forms: Be able to visualise and represent 2D and 3D forms including two dimensional representations of 3D objects. You should be able to:

deduce that a compound is ionic from a diagram of its structure in one of the specified forms

describe the limitations of using dot and cross, ball and stick, two and three dimensional diagrams to represent a giant ionic structure

work out the empirical formula of an ionic compound from a given model or diagram that shows the ions in the structure.

You should be familiar with the structure of sodium chloride but do not need to know the structures of other ionic compounds.

Introduction to Chemical Bonding

Ionic bonding and ionic compounds and their properties

Quiz on the Structure, Properties and Chemical Bonding of Materials

2.1.4 Covalent bonding

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 9 "Bonding, structure and properties of matter")

Know that when atoms share pairs of electrons, they form covalent bonds. These bonds between atoms are strong. Covalently bonded substances may consist of small molecules.

You should be able to recognise common substances that consist of small molecules from their chemical formula.

Some covalently bonded substances have very large molecules, such as polymers.

Some covalently bonded substances have giant covalent structures, such as diamond and silicon dioxide.

Be able to represent the covalent bonds in molecules and giant structures in various forms.

Recognise substances as small molecules, polymers or giant structures from diagrams showing their bonding

You should be able to:

draw dot and cross diagrams for the molecules of hydrogen, chlorine, oxygen, nitrogen, hydrogen chloride, water, ammonia and methane

represent the covalent bonds in small molecules, in the repeating units of polymers and in part of giant covalent structures, using a line to represent a single bond

describe the limitations of using dot and cross, ball and stick, two and three-dimensional diagrams to represent molecules or giant structures

deduce the molecular formula of a substance from a given model or diagram in these forms showing the atoms and bonds in the molecule.

Introduction to Chemical Bonding

Covalent bonding and small molecules and their properties

Quiz on the Structure, Properties and Chemical Bonding of Materials

2.1.5 Metallic bonding

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 9 "Bonding, structure and properties of matter")

Know that metals consist of giant structures of atoms arranged in a regular pattern. The electrons in the outer shell of metal atoms are delocalised and so are free to move through the whole structure. The sharing of delocalised electrons gives rise to strong metallic bonds. The bonding in metals may be represented in the following form: Be able to recognise substances as metallic giant structures from diagrams showing their bonding. Be able to visualise and represent 2D and 3D forms including two dimensional representations of 3D objects.

Introduction to Chemical Bonding

Metallic bonding, properties and uses of metals

Quiz on the Structure, Properties and Chemical Bonding of Materials


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

Topic 9 Bonding, structure and properties of matter QUIZ (AQA GCSE science-chemistry)

2.2.1 The three states of matter

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 9 "Bonding, structure and properties of matter")

Know that the three states of matter are solid, liquid and gas. Melting and freezing take place at the melting point, boiling and condensing take place at the boiling point.

The three states of matter can be represented by a simple model. In this model, particles are represented by small solid spheres. Particle theory can help to explain melting, boiling, freezing and condensing. The amount of energy needed to change state from solid to liquid and from liquid to gas depends on the strength of the forces between the particles of the substance. The nature of the particles involved depends on the type of bonding and the structure of the substance. The stronger the forces between the particles the higher the melting point and boiling point of the substance.

(HT only) Limitations of the simple model in describing changes of state include that it assumes there are no forces between the spheres, that all particles are represented as inelastic spheres and that the spheres are solid.

Be able to visualise and represent 2D and 3D forms including two dimensional representations of 3D objects. You should be able to:

predict the states of substances at different temperatures given appropriate data

explain the different temperatures at which changes of state occur in terms of energy transfers and types of bonding

recognise that atoms themselves do not have the bulk properties of materials

(HT only) explain the limitations of the particle theory in relation to changes of state when particles are represented by solid inelastic spheres which have no forces between them.

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

Multiple choice quiz on States of Matter (gases, liquids & solids) and State Changes

Note that in the pages on types of chemical bonding and structure, there is a section on relating their structure to their physical properties.

Ionic compounds - structure and properties

Covalent small simple molecules - structure and properties

Macromolecules, giant covalent structures, polymers - structure and properties

Metals – structure and properties

2.2.2 State symbols

Know that in chemical equations, the three states of matter are shown as (s), (l) and (g), with (aq) for aqueous solutions. You should be able to include appropriate state symbols in chemical equations for the reactions in this specification.

In most equations on my website I've included the state symbols appropriate to the equation.

2.2.3 Properties of ionic compounds

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 9 "Bonding, structure and properties of matter")

Know that ionic compounds have regular structures (giant ionic lattices) in which there are strong electrostatic forces of attraction in all directions between oppositely charged ions.

These compounds have high melting points and high boiling points because of the large amounts of energy needed to break the many strong bonds.

When melted or dissolved in water, ionic compounds conduct electricity because the ions are free to move and so charge can flow.

Knowledge of the structures of specific ionic compounds other than sodium chloride is not required.

Ionic bonding and ionic compounds and their properties

Quiz on the Structure, Properties and Chemical Bonding of Materials

2.2.4 Properties of small molecules

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 9 "Bonding, structure and properties of matter")

Know that substances that consist of small molecules are usually gases or liquids that have relatively low melting points and boiling points.

These substances have only weak forces between the molecules (intermolecular forces). It is these intermolecular forces that are overcome, not the covalent bonds, when the substance melts or boils.

The intermolecular forces increase with the size of the molecules, so larger molecules have higher melting and boiling points.

These substances do not conduct electricity because the molecules do not have an overall electric charge.

You should be able to use the idea that intermolecular forces are weak compared with covalent bonds to explain the bulk properties of molecular substances.

Covalent bonding and small molecules and their properties

Quiz on the Structure, Properties and Chemical Bonding of Materials

2.2.5 Polymers

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 9 "Bonding, structure and properties of matter")

Appreciate that polymers have very large molecules. The atoms in the polymer molecules are linked to other atoms by strong covalent bonds. The intermolecular forces between polymer molecules are relatively strong and so these substances are solids at room temperature.

You should be able to recognise polymers from diagrams showing their bonding and structure.

Macromolecules and polymers (compared with giant covalent structures)

More detailed notes on polymer structure (lots of examples, most studied in detail later in course)

Comparing types of polymers (lots of examples, most studied in detail later in course)

2.2.6 Giant covalent structures

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 9 "Bonding, structure and properties of matter")

Know that substances that consist of giant covalent structures are solids with very high melting points. All of the atoms in these structures are linked to other atoms by strong covalent bonds. These bonds must be overcome to melt or boil these substances. Diamond and graphite (forms of carbon) and silicon dioxide (silica) are examples of giant covalent structures.

Be able to recognise giant covalent structures from diagrams showing their bonding.

Be able to visualise and represent 2D and 3D forms including two dimensional representations of 3D objects.

Covalent bonding and giant structures and their properties and uses

Quiz on the Structure, Properties and Chemical Bonding of Materials

2.2.7 Properties of metals and alloys

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 9 "Bonding, structure and properties of matter")

Know that metals have giant structures of atoms with strong metallic bonding. This means that most metals have high melting and boiling points.

In metals, the layers of atoms are able to slide over each other. This means metals can be bent and shaped.

Most metals in everyday use are alloys. Pure metals eg copper, gold, iron and aluminium, are too soft for many uses and so are mixed with other metals to make alloys which are harder.

The different sizes of atoms in an alloy distort the layers in the structure, making it more difficult for them to slide over each other, so alloys are harder than pure metals. You should be able to explain why an alloy of a metal is harder than the pure metal.

Metallic bonding, properties and uses of metals

The Transition Metals plus aluminium) (lots of examples

2.2.8 Metals as conductors

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 9 "Bonding, structure and properties of matter")

Know that metals are good conductors of electricity because the delocalised electrons in the metal carry electrical charge through the metal. Metals are good conductors of thermal energy because energy is transferred by the mobile delocalised electrons.

Properties and uses of metals


2.3 Structure and bonding of carbon

Topic 9 Bonding, structure and properties of matter QUIZ (AQA GCSE science-chemistry)

2.3.1 Diamond

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 9 "Bonding, structure and properties of matter")

Know that in diamond, each carbon atom forms four covalent bonds with other carbon atoms in a giant covalent structure, so diamond is very hard, has a very high melting point and does not conduct electricity.

Be able to explain the properties of diamond in terms of its structure and bonding.

Be able to visualise and represent 2D and 3D forms including two dimensional representations of 3D objects.

Covalent bonding and giant structures and their properties and uses

2.3.2 Graphite

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 9 "Bonding, structure and properties of matter")

Know that in graphite, each carbon atom forms three covalent bonds with three other carbon atoms, forming layers of hexagonal rings which have no covalent bonds between the layers.

In graphite, one electron from each carbon atom is delocalised.

You should be able to explain the properties of graphite in terms of its structure and bonding.

You should know that graphite is similar to metals in that it has delocalised electrons.

Covalent bonding and giant structures and their properties and uses

2.3.3 Graphene and fullerenes

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 9 "Bonding, structure and properties of matter")

Graphene is a single layer of graphite and has properties that make it useful in electronics and composites.

You should be able to explain the properties of graphene in terms of its structure and bonding.

Fullerenes are molecules of carbon atoms with hollow shapes. The structure of fullerenes is based on hexagonal rings of carbon atoms but they may also contain rings with five or seven carbon atoms. The first fullerene to be discovered was Buckminsterfullerene (C60) which has a spherical shape.

Carbon nanotubes are cylindrical fullerenes with very high length to diameter ratios. Their properties make them useful for nanotechnology, electronics and materials.

You should be able to:

recognise graphene and fullerenes from diagrams and descriptions of their bonding and structure

give examples of the uses of fullerenes, including carbon nanotubes.

Covalent bonding and giant structures and their properties and uses

Nanochemistry - Fullerenes; bucky balls and carbon nanotubes

Nanochemistry - Graphene


Topic 10 Quantitative chemistry

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 10 "Quantitative chemistry")

Chemists use quantitative analysis to determine the formulae of compounds and the equations for reactions. Given this information, analysts can then use quantitative methods to determine the purity of chemical samples and to monitor the yield from chemical reactions.

Chemical reactions can be classified in various ways. Identifying different types of chemical reaction allows chemists to make sense of how different chemicals react together, to establish patterns and to make predictions about the behaviour of other chemicals.

Chemical equations provide a means of representing chemical reactions and are a key way for chemists to communicate chemical ideas.

My CHEMICAL CALCULATIONS INDEX

AQA GCSE (Grade 9-1) Combined science chemistry Topic 3 Quantitative chemistry quiz content: Quantitative chemistry, chemistry calculations, law of conservation of mass, balancing chemical equations, relative formula mass, reacting mass calculations

Topic 10 Quantitative chemistry QUIZ (AQA GCSE combined science trilogy chemistry)

HT = higher tier (harder - usually more theory & depth) and FT = foundation tier (easier)  1st drafts of AQA quizzes



3.1 Conservation of mass and the quantitative interpretation of chemical equations

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 10 "Quantitative chemistry")

3.1.1 Conservation of mass and balanced chemical equations

Know the law of conservation of mass states that no atoms are lost or made during a chemical reaction so the mass of the products equals the mass of the reactants.

This means that chemical reactions can be represented by symbol equations which are balanced in terms of the numbers of atoms of each element involved on both sides of the equation.

You should understand the use of the multipliers in equations in normal script before a formula and in subscript within a formula.

Law of Conservation of Mass and simple reacting mass calculations

How to read a chemical formula and balance chemical equations

Type in answer quiz on the law of conservation of mass

Multiple choice quiz on the law of conservation of mass

3.1.2 Relative formula mass  

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 10 "Quantitative chemistry")

Know the relative formula mass (Mr) of a compound is the sum of the relative atomic masses of the atoms in the numbers shown in the formula.

In a balanced chemical equation, the sum of the relative formula masses of the reactants in the quantities shown equals the sum of the relative formula masses of the products in the quantities shown.

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

More reacting mass ratio calculations of reactants and products from equations (NOT using moles)

Type in answer quiz on relative formula mass

Multiple Choice quiz on relative formula mass

3.1.3 Mass changes when a reactant or product is a gas

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 10 "Quantitative chemistry")

Know that some reactions may appear to involve a change in mass but this can usually be explained because a reactant or product is a gas and its mass has not been taken into account.

For example: when a metal reacts with oxygen the mass of the oxide produced is greater than the mass of the metal or in thermal decompositions of metal carbonates carbon dioxide is produced and escapes into the atmosphere leaving the metal oxide as the only solid product.

You should be able to explain any observed changes in mass in non-enclosed systems during a chemical reaction given the balanced symbol equation for the reaction and explain these changes in terms of the particle model.

You should have experienced investigating of mass changes using various apparatus.

Law of Conservation of Mass and simple reacting mass calculations

3.1.4 Chemical measurements

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 10 "Quantitative chemistry")

Whenever a measurement is made there is always some uncertainty about the result obtained.

You should be able to:

represent the distribution of results and make estimations of uncertainty

use the range of a set of measurements about the mean as a measure of uncertainty.


3.2 Use of amount of substance in relation to masses of pure substances

Topic 10 Quantitative chemistry QUIZ (AQA GCSE combined science trilogy chemistry)

3.2.1 Moles (HT only)

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 10 "Quantitative chemistry")

Chemical amounts are measured in moles. The symbol for the unit mole is mol.

The mass of one mole of a substance in grams is numerically equal to its relative formula mass.

One mole of a substance contains the same number of the stated particles, atoms, molecules or ions as one mole of any other substance.

The number of atoms, molecules or ions in a mole of a given substance is the Avogadro constant. The value of the Avogadro constant is 6.02 x 1023 per mole.

You should understand that the measurement of amounts in moles can apply to atoms, molecules, ions, electrons, formulae and equations, for example that in one mole of carbon (C) the number of atoms is the same as the number of molecules in one mole of carbon dioxide (CO2).

You should be able to use the relative formula mass of a substance to calculate the number of moles in a given mass of that substance and vice versa.

Be able to recognise and use expressions in decimal form. Be able to recognise and use expressions in standard form.

Be able to use an appropriate number of significant figures.

Be able to understand and use the symbols: =, <, <<, >>, >, , ~

Be able to change the subject of an equation.

Introducing moles: The connection between moles, mass and formula mass - the basis of reacting mole ratio calculations (relating reacting masses and formula mass), Avogadro constant

Introduction to moles type in answer QUIZ

Introduction to moles multiple choice QUIZ

3.2.2 Amounts of substances in equations (HT only)

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 10 "Quantitative chemistry")

The masses of reactants and products can be calculated from balanced symbol equations. Chemical equations can be interpreted in terms of moles. For example: Mg + 2HCI ===> MgCI2 + H2 shows that one mole of magnesium reacts with two moles of hydrochloric acid to produce one mole of magnesium chloride and one mole of hydrogen gas.

You should be able to:

calculate the masses of substances shown in a balanced symbol equation

calculate the masses of reactants and products from the balanced symbol equation and the mass of a given reactant or product.

recognise and use expressions in decimal form

use ratios, fractions and percentages

change the subject of an equation

substitute numerical values into algebraic equations using appropriate units for physical quantities.

Reacting mass ratio calculations of reactants and products from equations (NOT using moles)

Mole ratio calculations - equation interpretation and construction of balanced chemical equations

Working out formula from reacting masses type in answer QUIZ

Working out formula from reacting masses multiple choice QUIZ

Type in answer QUIZ on reacting masses

Multiple choice QUIZ on reacting masses

3.2.3 Using moles to balance equations (HT only) (AQA GCSE Combined Science Trilogy Chemistry paper 1 chemistry 1)

Know that the balancing numbers in a symbol equation can be calculated from the masses of reactants and products by converting the masses in grams to amounts in moles and converting the numbers of moles to simple whole number ratios. You should be able to:

balance an equation given the masses of reactants and products

change the subject of a mathematical equation

substitute numerical values into algebraic equations using appropriate units for physical quantities.

Mole ratio calculations - equation interpretation and construction of balanced chemical equations

3.2.4 Limiting reactants (HT only)

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 10 "Quantitative chemistry")

Know that in a chemical reaction involving two reactants, it is common to use an excess of one of the reactants to ensure that all of the other reactant is used. The reactant that is completely used up is called the limiting reactant because it limits the amount of products.

You should be able to explain the effect of a limiting quantity of a reactant on the amount of products it is possible to obtain in terms of amounts in moles or masses in grams.

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

3.2.5 Concentration of solutions (HT only)

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 10 "Quantitative chemistry")

Know that many chemical reactions take place in solutions. The concentration of a solution can be measured in mass per given volume of solution, eg grams per dm3 (g/dm3).

You should be able to:

calculate the mass of solute in a given volume of solution of known concentration in terms of mass per given volume of solution

be able to use ratios, fractions and percentages

be able to change the subject of an equation.

(HT only) Be able to explain how the mass of a solute and the volume of a solution is related to the concentration of the solution

Concentration of solution in terms of mass and volume

Molarity, volumes and solution concentrations (g/dm3 examples too, molarity not needed by combined science trilogy students)


Topic 11 Chemical changes

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 11 "Chemical changes")

Appreciate that understanding of chemical changes began when people began experimenting with chemical reactions in a systematic way and organizing their results logically. Knowing about these different chemical changes meant that scientists could begin to predict exactly what new substances would be formed and use this knowledge to develop a wide range of different materials and processes. It also helped biochemists to understand the complex reactions that take place in living organisms. The extraction of important resources from the earth makes use of the way that some elements and compounds react with each other and how easily they can be ‘pulled apart’.

AQA GCSE (Grade 9-1) Combined Science Trilogy Chemistry Topic 11 Chemical Changes quiz content:  Oxidation and reduction, metal oxides, reactivity series of metals, extraction of metals, reactions of acids, salt preparations

Topic 11 Chemical Changes QUIZ (AQA GCSE combined science trilogy chemistry)

HT = higher tier (harder - usually more theory & depth) and FT = foundation tier (easier)  1st drafts of AQA quizzes



4.1 Reactivity of metals

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 11 "Chemical changes")

4.1.1 Metal oxides

Know that metals react with oxygen to produce metal oxides.

The reactions are oxidation reactions because the metals gain oxygen.

You should be able to explain reduction and oxidation in terms of loss or gain of oxygen.

The Reactivity Series of Metals - reactions with oxygen, water or acids and displacement reactions

Introduction to oxidation and reduction and their application to reactions

4.1.2 The reactivity series 

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 11 "Chemical changes")

Know that when metals react with other substances the metal atoms form positive ions. The reactivity of a metal is related to its tendency to form positive ions. Metals can be arranged in order of their reactivity in a reactivity series.

The metals potassium, sodium, lithium, calcium, magnesium, zinc, iron and copper can be put in order of their reactivity from their reactions with water and dilute acids.

The non-metals hydrogen and carbon are often included in the reactivity series.

A more reactive metal can displace a less reactive metal from a compound.

You should be able to:

recall and describe the reactions, if any, of potassium, sodium, lithium, calcium, magnesium, zinc, iron and copper with water or dilute acids and where appropriate, to place these metals in order of reactivity

explain how the reactivity of metals with water or dilute acids is related to the tendency of the metal to form its positive ion

deduce an order of reactivity of metals based on experimental results.

The reactions of metals with water and acids are limited to room temperature and do not include reactions with steam.

You should have experienced mixing of reagents to explore chemical changes and/or products.

The Reactivity Series of Metals - reactions with oxygen, water or acids and displacement reactions

Metal Reactivity Series Experiments-Observations

Alkali metals reactivity series

Multiple choice quiz on the Reactivity Series of Metals

Gap-fill worksheet on The Reactivity of Metals

Structured question worksheet on the Metal Reactivity Series * (answers)

4.1.3 Extraction of metals and reduction  

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 11 "Chemical changes")

Know that unreactive metals such as gold are found in the Earth as the metal itself but most metals are found as compounds that require chemical reactions to extract the metal.

Metals less reactive than carbon can be extracted from their oxides by reduction with carbon.

Reduction involves the loss of oxygen.

Your knowledge and understanding are limited to the reduction of oxides using carbon.

Knowledge of the details of processes used in the extraction of metals is not required.

You should be able to:

interpret or evaluate specific metal extraction processes when given appropriate information

identify the substances which are oxidised or reduced in terms of gain or loss of oxygen.

Introduction to Metal Extraction

Introduction to oxidation and reduction theory and application to reactions

Multiple choice QUIZ on metal extraction

Gap–word–fill exercise on metal extraction

4.1.4 Oxidation and reduction in terms of electrons (HT only)

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 11 "Chemical changes")

Know that oxidation is the loss of electrons and reduction is the gain of electrons.

You should be able to:

write ionic equations for displacement reactions

identify in a given reaction, symbol equation or half equation which species are oxidised and which are reduced.

Introduction to oxidation and reduction theory and their application to reactions


4.2 Reactions of acids 

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 11 "Chemical changes")

Topic 11 Chemical Changes QUIZ (AQA GCSE combined science trilogy chemistry)

Reactions of acids

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

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

Word equation answers and symbol equation answers

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

Matching pair quiz on Acids, Bases, Salts and pH

4.2.1 Reactions of acids with metals

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 11 "Chemical changes")

Know that acids react with some metals to produce salts and hydrogen - observations, equations etc..

(HT only) You should be able to:

explain in terms of gain or loss of electrons, that these are redox reactions

identify which species are oxidised and which are reduced in given chemical equations.

Your knowledge of such reactions is limited to those of magnesium, zinc and iron with hydrochloric and sulfuric acids.

Reactions of acids with metals

The Reactivity Series of Metals

Introduction to oxidation and reduction theory and application to reactions

4.2.2 Neutralisation of acids and salt production

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 11 "Chemical changes")

Know that acids are neutralised by alkalis (eg soluble metal hydroxides) and bases (eg insoluble metal hydroxides and metal oxides) to produce salts and water, and also neutralised by metal carbonates to produce salts, water and carbon dioxide.

The particular salt produced in any reaction between an acid and a base or alkali depends on:

the acid used (hydrochloric acid produces chlorides, nitric acid produces nitrates, sulfuric acid produces sulfates)

the positive ions in the base, alkali or carbonate.

You should be able to:

predict products from given reactants

use the formulae of common ions to deduce the formulae of salts.

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

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

4.2.3 Soluble salts

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 11 "Chemical changes")

Know that soluble salts can be made from acids by reacting them with solid insoluble substances, such as metals, metal oxides, hydroxides or carbonates.

The solid is added to the acid until no more reacts and the excess solid is filtered off to produce a solution of the salt.

Salt solutions can be crystallised to produce solid salts.

You should be able to describe how to make pure, dry samples of named soluble salts from information provided.

You should have prepared of a pure, dry sample of a soluble salt from an insoluble oxide or carbonate using a bunsen burner to heat dilute acid and a water bath or electric heater to evaporate the solution.

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

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

4.2.4 The pH scale and neutralisation

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 11 "Chemical changes")

Know that acids produce hydrogen ions (H+) in aqueous solutions.

Aqueous solutions of alkalis contain hydroxide ions (OH).

The pH scale, from 0 to 14, is a measure of the acidity or alkalinity of a solution, and can be measured using universal indicator or a pH probe.

A solution with pH 7 is neutral. Aqueous solutions of acids have pH values of less than 7 and aqueous solutions of alkalis have pH values greater than 7.

In neutralisation reactions between an acid and an alkali, hydrogen ions react with hydroxide ions to produce water.

This reaction can be represented by the equation: H+(aq) + OH(aq) ===> H2O(l)

You should be able to:

describe the use of universal indicator or a wide range indicator to measure the approximate pH of a solution

use the pH scale to identify acidic or alkaline solutions

You should have investigated the pH changes when a strong acid neutralises a strong alkali - pH curve.

Everyday examples of acid-alkali chemistry - uses of acids and alkalis

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

Changes in pH in a neutralisation reaction

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

Titration type in answer QUIZ

Titration multiple choice QUIZ

4.2.5 Strong and weak acids (HT only)

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 11 "Chemical changes")

Know that a strong acid is completely ionised in aqueous solution. Examples of strong acids are hydrochloric, nitric and sulfuric acids.

A weak acid is only partially ionised in aqueous solution. Examples of weak acids are ethanoic, citric and carbonic acids.

For a given concentration of aqueous solutions, the stronger an acid, the greater the hydrogen ion concentration and the lower the pH.

As the pH decreases by one unit, the hydrogen ion concentration of the solution increases by a factor of 10.

You should be able to:

use and explain the terms dilute and concentrated (in terms of amount of substance), and weak and strong (in terms of the degree of ionisation) in relation to acids

describe neutrality and relative acidity in terms of the effect on hydrogen ion concentration and the numerical value of pH (whole numbers only).

You should have measured the pH of different acids at different concentrations.

Be able to make order of magnitude calculations.

More on acid-base theory and weak and strong acids and their properties


4.3 Electrolysis  

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 11 "Chemical changes")

Topic 11 Chemical Changes QUIZ (AQA GCSE combined science trilogy chemistry)

4.3.1 The process of electrolysis

Know that when an ionic compound is melted or dissolved in water, the ions are free to move about within the liquid or solution. These liquids and solutions are able to conduct electricity and are called electrolytes.

Passing an electric current through electrolytes causes the ions to move to the electrodes. Positively charged ions move to the negative electrode (the cathode), and negatively charged ions move to the positive electrode (the anode).

Ions are discharged at the electrodes producing elements. This process is called electrolysis.

(HT only) Throughout Section 4.3 you should be able to write half equations for the reactions occurring at the electrodes during electrolysis, and you may be required to complete and balance supplied half equations.

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

Summary of electrode half-equations and products

4.3.2 Electrolysis of molten ionic compounds 

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 11 "Chemical changes")

Know that when a simple ionic compound (eg lead bromide) is electrolysed in the molten state using inert electrodes, the metal (lead) is produced at the cathode and the non-metal (bromine) is produced at the anode.

You should be able to predict the products of the electrolysis of binary ionic compounds in the molten state.

Your teacher may have demonstrated this kind of electrolysis using anhydrous zinc chloride.

I had no problem electrolysing lead bromide in a crucible using carbon electrodes - BUT in a fume cupboard.

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

4.3.3 Using electrolysis to extract metals 

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 11 "Chemical changes")

Know that metals can be extracted from molten compounds using electrolysis. Electrolysis is used if the metal is too reactive to be extracted by reduction with carbon or if the metal reacts with carbon. Large amounts of energy are used in the extraction process to melt the compounds and to produce the electrical current.

Aluminium is manufactured by the electrolysis of a molten mixture of aluminium oxide and cryolite. The mixture has a lower melting point than pure aluminium oxide. Aluminium forms at the negative electrode (cathode) and oxygen at the positive electrode (anode). The positive electrode (anode) is made of carbon, which reacts with the oxygen to produce carbon dioxide and so must be continually replaced.

You should be able to:

explain why a mixture is used as the electrolyte

explain why the positive electrode must be continually replaced

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

Introduction to Metal Extraction

Electrolysis of copper(II) sulfate solution (is used to extract copper from dissolved ore residues)

4.3.4 Electrolysis of aqueous solutions 

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 11 "Chemical changes")

Know that the ions discharged when an aqueous solution is electrolysed using inert electrodes depend on the relative reactivity of the elements involved.

At the negative electrode (cathode), hydrogen is produced if the metal is more reactive than hydrogen.

At the positive electrode (anode), oxygen is produced unless the solution contains halide ions when the halogen is produced.

This happens because in the aqueous solution water molecules break down producing hydrogen ions and hydroxide ions that are discharged.

You should be able to predict the products of the electrolysis of aqueous solutions containing a single ionic compound.

You should have investigated what happens when aqueous solutions are electrolysed using inert electrodes.

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

Electrolysis of sodium chloride solution (brine) and other halide solutions - bromides, iodides

Electrolysis of copper(II) sulfate solution (inert or copper electrodes) and electroplating

Electrolysis of copper(II) chloride solution (inert electrodes)

Electrolysis of hydrochloric acid

4.3.5 Representation of reactions at electrodes as half equations (HT only)

Know that during electrolysis, at the cathode (negative electrode), positively charged ions gain electrons and so the reactions are reductions.

At the anode (positive electrode), negatively charged ions lose electrons and so the reactions are oxidations.

Reactions at electrodes can be represented by half equations, for example:

2H+ + 2e- ===> H2    a reduction, electron gain

and   4OH- ===> O2 + 2H2O + 4e-    or    4OH- – 4e- ==> O2 + 2H2O   an oxidation, electron loss

Summary of electrode half-equations and products

(lots of examples explained in more detail on the specific electrolysis pages linked to  above)


Topic 12 Energy changes 

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 12 "Energy changes")

Appreciate that energy changes are an important part of chemical reactions. The interaction of particles often involves transfers in energy due to the breaking and formation of bonds. Reactions in which energy is released to the surroundings are exothermic reactions, while those that take in heat (absorb) thermal energy are endothermic.

These interactions between particles can produce heating or cooling effects that are used in a range of everyday applications.

Some interactions between ions in an electrolyte result in the production of electricity.

Cells and batteries use these chemical reactions to generate electricity.

Electricity can also be used to decompose (split) ionic substances and is a useful means of producing elements that are too expensive to extract any other way.

Energy Changes Notes Index

Quiz on Energy Changes in Chemical Reactions

AQA GCSE (Grade 9-1) GCSE chemistry/combined science trilogy Topic 12 Energy Changes quiz content: Energy changes in chemistry, exothermic and endothermic reactions, energy transfers, reaction profiles, bond energy calculations (HT only), need questions on cells and batteries for GCSE Chemistry ONLY

Topic 12 Energy Changes QUIZ (AQA GCSE combined science trilogy)

HT = higher tier (harder - usually more theory & depth) and FT = foundation tier (easier)  1st drafts of AQA quizzes



5.1 Exothermic and endothermic reactions  

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 12 "Energy changes")

5.1.1 Energy transfer during exothermic and endothermic reactions

Know that energy is conserved in chemical reactions. The amount of energy in the universe at the end of a chemical reaction is the same as before the reaction takes place. If a reaction transfers energy to the surroundings the product molecules must have less energy than the reactants, by the amount transferred.

An exothermic reaction is one that transfers energy to the surroundings so the temperature of the surroundings increases. Exothermic reactions include combustion, many oxidation reactions and neutralisation. Everyday uses of exothermic reactions include selfheating cans and hand warmers.

An endothermic reaction is one that takes in energy from the surroundings so the temperature of the surroundings decreases. Endothermic reactions include thermal decompositions and the reaction of citric acid and sodium hydrogencarbonate. Some sports injury packs are based on endothermic reactions.

You should be able to:

distinguish between exothermic and endothermic reactions on the basis of the temperature change of the surroundings

evaluate uses and applications of exothermic and endothermic reactions given appropriate information.

Limited to measurement of temperature change.

Calculation of energy changes or ΔH is not required.

You should have investigated the variables that affect temperature changes in reacting solutions such as, eg acid plus metals, acid plus carbonates, neutralisations and displacement of metals.

Calorimeter methods of determining energy changes and EXAMPLES of experiments you can do

Heat changes in chemical/physical changes - exothermic and endothermic

Quiz on Energy Changes in Chemical Reactions

5.1.2 Reaction profiles

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 12 "Energy changes")

Know that chemical reactions can occur only when reacting particles collide with each other and with sufficient energy. The minimum amount of energy that particles must have to react is called the activation energy.

Reaction profiles can be used to show the relative energies of reactants and products, the activation energy and the overall energy change of a reaction.

You should be able to:

draw simple reaction profiles (energy level diagrams) for exothermic and endothermic reactions showing the relative energies of reactants and products, the activation energy and the overall energy change, with a curved line to show the energy as the reaction proceeds

use reaction profiles to identify reactions as exothermic or endothermic

explain that the activation energy is the energy needed for a reaction to occur

Particle model of the collision theory of chemical reaction rate factors

Activation energy and reaction profiles, catalysts and activation energy

Quiz on Energy Changes in Chemical Reactions

5.1.3 The energy change of reactions (HT only

(revision notes summary for AQA 9-1 GCSE Combined Science Trilogy: Chemistry Paper 1, Topic 12 "Energy changes")

Know that during a chemical reaction:

energy must be supplied to break bonds in the reactants

energy is released when bonds in the products are formed.

The energy needed to break bonds and the energy released when bonds are formed can be calculated from bond energies.

The difference between the sum of the energy needed to break bonds in the reactants and the sum of the energy released when bonds in the products are formed is the overall energy change of the reaction.

In an exothermic reaction, the energy released from forming new bonds is greater than the energy needed to break existing bonds.

In an endothermic reaction, the energy needed to break existing bonds is greater than the energy released from forming new bonds.

You should be able to calculate the energy transferred in chemical reactions using bond energies supplied.

Introduction to bond energy/enthalpy calculations

Quiz on Energy Changes in Chemical Reactions


PAST PAPERS   (Practice exam question papers for revising AQA 9-1 GCSE Combined Science Trilogy Chemistry Paper 1, Topic 8 "Atomic structure and the periodic table", Topic 9 "Bonding, structure and the properties of matter", Topic 10 "Quantitative chemistry", Topic 11 "Chemical changes", Topic 12 "Energy changes")



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AQA GCSE (Grade 9-1) Combined Science: Trilogy Chemistry PAST PAPERS (syllabus specification 8464 for biology, chemistry and physics topics) (see separate page for Combined Science Trilogy Chemistry 2 Papers)

Specifications - syllabuses, past exam papers, specimen practice question papers

AQA GCSE Grade 9-1 Combined Science: Trilogy Foundation Tier Chemistry (FT)

AQA GCSE Grade 9-1 Combined Science: Trilogy Higher Tier Chemistry (HT)

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