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Revision summary help OCR GCSE 9-1 Gateway Combined Science A 1st chemistry A exam paper - learning objectives for exam papers OCR Level 1/2 GCSE (Grade 9-1) in Combined Science A (Gateway Science) (J250) FT Paper 3/HT Paper 9 Chemistry - OCR (Grade 9-1) GCSE Combined Science chemistry Topic C1 "Particles", Topic C2 "Elements, compounds and mixtures", Topic C3 "Chemical reactions", Topic CS7 "Practical skills" for Gateway combined science 2020 chemistry exam papers onwards LINK GCSE Gateway Combined Science 2nd chemistry paper C1-6, CS7 LINK for OCR Gateway Science GCSE CHEMISTRY 1st paper C1-3, C7 LINK for OCR Gateway Science GCSE CHEMISTRY 2nd paper C1-C7 This is a BIG website, you need to take time to explore it [SEARCH BOX] Use your mobile phone 'landscape' orientation? See also OCR 21st Century Sciences B Revision Links email doc brown - query? or comment? For ALL other exam papers, use and bookmark the link below
Syllabus-specification CONTENT INDEX of revision summary notes Revision summaries for OCR Gateway GCSE 9-1 Combined Science A chemistry FT Paper 3/HT Paper 9 (this page) What's assessed in this paper? (for OCR 9-1 GCSE Gateway Combined Science - chemistry topics) The 1st chemistry paper assesses Topics C1, C2, C3 and CS7 Revision SUMMARY of Topic C1: Particles: Containing sections Revision SUMMARY of Topic C2: Elements, compounds and mixtures: Containing sections C2.1 Purity and separating mixtures, Revision SUMMARY of Topic C3: Chemical reactions: Containing sections C3.1 Introducing chemical reactions, C3.3 Types of chemical reactions, Summaries for OCR GCSE Gateway Combined Science A FT chemistry Paper 2/HT Paper 4 (separate page) What is assessed in this paper? (for OCR 9-1 GCSE Gateway Combined Science - chemistry topics) 2nd chemistry paper assesses Topics C4, C5, C6 and CS7, BUT assumes knowledge of Topics C1, C2, C3 Revision SUMMARY of Topic C4: Predicting and identifying reactions and products: Containing sections C4.1 Predicting chemical reactions Revision SUMMARY of Topic C5: Monitoring and controlling chemical reactions: Containing sections C5.1 Controlling reactions (Topic 5.1 Combined science) C5.2 Equilibria (Topic 5.2 Combined Science) Revision SUMMARY of Topic C6: Global challenges: Containing sections C6.1 Improving processes and products, C6.2 Interpreting & interacting with Earth systems
TOPICS OCR Gateway GCSE 9-1 Combined Science A chemistry FT Paper 3/HT Paper 9 Topic C1: Particles
Chemistry key ideas for all topics (for OCR 9-1 GCSE Gateway Combined Science - chemistry topics) Chemistry is the science of the composition, structure, properties and reactions of matter, understood in terms of atoms, atomic particles and the way they are arranged and link together. It is concerned with the synthesis, formulation, analysis and characteristic properties of substances and materials of all kinds. You should appreciate the achievements of chemistry in showing how the complex and diverse phenomena of both the natural and man-made worlds can be described in terms of a small number of key ideas which are of universal application, and which can be illustrated in the separate topics set out below. These ideas include:
A page of important ideas, concepts and definitions for chemistry students Topic C1 Particles (Revision for OCR Gateway Science GCSE 9-1 Combined Science A, 1st biology paper Topic C1 "Particles", papers 3/9) OCR Gateway Science GCSE 9-1 Combined Science Topic C1 "Particles" quiz content for chemistry 1: Particle models - states of matter - gases, liquids & solids, state changes, sub-atomic model of an atom, history of atomic structure theory, atomic notation of atoms (higher tier HT/foundation tier FT)
For HT/FT students
HT = higher tier (harder - usually more theory & depth) and FT = foundation tier (easier) C1.1 The particle model
Appreciate you can use a particle model to explain the different states of matter. A simple particle model can be to used to represent the arrangement of particles in the different states of matter and to explain observations during changes in state. It does not, however, explain why different materials have different properties. This explanation is that the particles themselves and how they are held together must be different in some way. Elements are substances that are made up of only one type of atom and atoms of different elements can combine to make compounds. You should be familiar with the different states of matter and their properties. You should also be familiar with changes of state in terms of the particle model. You should have sufficient understanding of the particle model to be able to apply it to unfamiliar materials and contexts. Common misconceptions - the idea that matter is continuous eg the space between gas particles is filled or non-existent, or that particles expand when they are heated. You also need to appreciate the concept of changes in state being reversible. Other problem concepts might be when you represent three dimensional shapes in two dimensions and vice versa when looking at chemical structures e.g. allotropes of carbon. C1.1a Be able to describe the main features of the particle model in terms of states of matter and change of state C1.1b Be able to explain in terms of the particle model the distinction between physical changes and chemical changes C1.1c (HT only) Be able to explain the limitations of the particle model in relation to changes of state when particles are represented by inelastic spheres (e.g. like bowling balls). Appreciate that it does not take into account the forces of attraction between particles, the size of particles and the space between them.
States of Matter - particle theory - gas, liquid & solid properties-behaviour, state changes Revision Notes Multiple choice quiz on States of Matter (gases, liquids & solids) and State Changes Easy multiple choice quiz on "Particle models of gases, liquids and solids and solutions" 4 Easy word-fill quizzes on "The Particles Model of Gases, Liquids and Solids" 7Gwf1 * 7Gwf2 * 7Gwf3 * 7Gwf4 3 Linked easy quizzes on "The States of Matter" States1mp * States2mp * States3mp (very basic questions)
C1.2 Atomic structure
An atom is the smallest component of an element that gives an element its property. These properties can be explained by models of atomic structure. Current models suggest that atoms are made of smaller sub-atomic particles called protons, neutrons and electrons. The models suggest that atoms are composed of a nucleus surrounded by electrons. The nucleus is composed of neutrons and protons. Atoms of each element have the same number of protons as electrons. Atoms of different elements have different numbers of protons. Atoms of the same element will have the same number of protons but may have different numbers of neutrons. Common misconceptions: understanding the concept of isotopes due to the fact you may think that neutral atoms have the same number of protons and neutrons. You may find it difficult to distinguish between the properties of atoms and molecules. Another common misconception is that a positive ion gains protons or a negative ion loses electrons i.e. that there is a change in the nucleus of the atom rather than a change in the number of electrons. Be able to relate size and scale of atoms to objects in the physical world and be able to estimate size and scale of atoms and nanoparticles C1.2a Be able to describe how and why the atomic model has changed over time including the models of Dalton, Thompson, Rutherford, Bohr, Geiger and Marsden. C1.2b Be able to describe the atom as a positively charged nucleus surrounded by negatively charged electrons, with the nuclear radius much smaller than that of the atom and with most of the mass in the nucleus C1.2c Know the typical size (order of magnitude) of atoms and small molecules - the concept that typical atomic radii and bond length are in the order of 10-10m C1.2d Know the relative charges and approximate relative masses of protons, neutrons and electrons C1.2e Be able to calculate numbers of protons, neutrons and electrons in atoms and ions, given atomic number and mass number of isotopes. Know the definitions of an ion, atomic number, mass number and an isotope and the standard notation to represent these terms. Atomic Structure - nucleus, electrons, isotopes, history etc. Revision Notes Multiple choice quiz on Atomic structure, isotopes Atomic Structure crossword puzzle * Answers Gap-fill worksheet on Atomic Structure Matching pair quiz on Atomic and electronic structure 1. fundamental particles Extra Word-fill quiz "Atomic structure and elements" Extra Word-fill quiz 2 "Atomic Structure"
Topic C2 Elements, compounds and mixtures (Revision for OCR Gateway Science GCSE 9-1 Combined Science A, 1st chemistry paper Topic C2 "Elements, compounds, mixtures", papers 3/9) OCR Gateway Science GCSE 9-1 Combined Science Topic C2 "Elements, compounds and mixtures" quiz content for chemistry 1: Separating mixtures, chemical bonding and properties of ionic, covalent and metallic structures (higher tier HT/foundation tier FT)
HT students
FT students
HT = higher tier (harder - usually more theory & depth) and FT = foundation tier (easier) C2.1 Purity and separating mixtures Know in chemical terms elements and compounds are pure substances and mixtures are impure substances. Chemically pure substances can be identified using melting point. Many useful materials that we to use today are mixtures. There are many methods of separating mixtures including filtration, crystallisation, distillation and chromatographic techniques. You should be familiar with the concept of pure substances. You should have met simple separation techniques of mixtures. Know about the identification of pure substances in terms of melting point, boiling point and chromatography. Common misconceptions: Don't confuse the word pure with natural (untampered with). Don't think that when a substance dissolves that the solution is pure and not a mixture. C2.1a Be able to explain what is meant by the purity of a substance, distinguishing between the scientific and everyday use of the word purity.
Filtration, evaporation, crystallisation, drying and decantation Revision Notes
C2.1b Be able to use melting point data to distinguish pure from impure substances. Practical - measurement of melting point. Definitions in chemistry eg atom, molecule, formula, element, compound, mixture, pure, impure etc. Notes Easy multiple choice quiz on "Atoms, elements, compounds and mixtures" (questions on basic chemistry) 4 Easy linked word-fill quizzes on "Atoms, Elements and Compounds" 8Ewf1 * 8Ewf2 * 8Ewf3 * 8Ewf4 5 Easy linked word-fill quizzes on "Compounds and Mixtures" 8Fwf1 * 8Fwf2 * 8Fwf3 * 8Fwf4 * 8Fwf5 Easy matching pair quiz on "Elements, Compounds and Mixtures" (matching particle model pictures) C2.1c Be able to calculate relative formula masses of species separately and in a balanced chemical equation. Know the definition of relative atomic mass, relative molecular mass and relative formula mass What is relative atomic mass? (Ar) and calculating relative atomic mass Revision Notes Calculating relative formula/molecular mass (Mr) of a compound or element molecule Revision Notes Type in answer quiz on relative formula mass Multiple Choice quiz on relative formula mass C2.1d Be able to deduce the empirical formula of a compound from the relative numbers of atoms present or from a model or diagram and vice versa Empirical formula and formula mass of a compound from reacting (examples near top of page) Revision Notes empirical formula & molecular formula of a compound/molecule (examples near top of page) Revision Notes C2.1e Be able to explain that many useful materials are formulations of mixtures including alloys. Metals – structure and properties (including alloys) Revision Notes The Transition Metals - alloys and aluminium Revision Notes Introduction to formulations and examples explained Revision Notes C2.1f Be able to describe and exemplify the processes of filtration, crystallisation, simple distillation, and fractional distillation - know the techniques of filtration, crystallisation, simple distillation and fractional distillation.
C2.1g Be able to describe the techniques of paper and thin layer chromatography - practical exercise using these techniques. C2.1h Know that chromatography involves a stationary and a mobile phase and that separation depends on the distribution between the phases - identification of the mobile and stationary phases C2.1i Be able to interpret chromatograms, including measuring Rf values know and use of the Rf formula. C2.1j Be able to suggest suitable purification techniques given information about the substances involved C2.1k Be able to suggest chromatographic methods for distinguishing pure from impure substances including paper, thin layer (TLC) and gas chromatography. Practical - using chromatography to identify mixtures of dyes in an unknown ink. Links for C2.f to C2.1k Distillation - Simple and Fractional Distillation Revision Notes Paper & thin layer chromatography (tlc) and gas chromatography (gc, glc) Revision Notes Filtration, evaporation, crystallisation, drying and decantation Revision Notes 4 linked easy quizzes on "Separation of Mixtures" 7Hwf1 * 7Hwf2 * 7Hwf3 * 7Hwf4
C2.2 Bonding (Revision for OCR Gateway Science GCSE 9-1 Combined Science A, 1st chemistry paper Topic C2 "Elements, compounds, mixtures", papers 3/9) A simple electron energy level model can be used to explain the basic chemical properties of elements. When chemical reactions occur, they can be explained in terms of losing, gaining or sharing of electrons. The ability of an atom to lose, gain or share electrons depends on its atomic structure. Atoms that lose electrons will bond with atoms that gain electrons. Electrons will be transferred between the atoms to form a positive ion and a negative ion. These ions attract one another in what is known as an ionic bond. Atoms that share electrons can bond with other atoms that share electrons to form a molecule. Atoms in these molecules are held together by covalent bonds. You should be familiar with the simple (Dalton) atomic model. Common misconceptions - appreciate that the nucleus of an atom does not change when an electron is lost, gained or shared, its sometimes difficult to predict the numbers of atoms that must bond in order to achieve a stable outer level of electrons, don't think chemical bonds are physical things made of matter (they are forces between particles). Don't think that pairs of ions such as Na+ and Cl– are molecules. Be aware of the 3D nature of bonding and therefore the shape of molecules. Be able to estimate size and scale of atoms and nanoparticles and be able to represent three dimensional shapes in two dimensions and vice versa when looking at chemical structures e.g. allotropes of carbon. You may also have to translate information between diagrammatic and numerical forms. C2.2a Be able to describe metals and non-metals and be able to explain the differences between them on the basis of their characteristic physical and chemical properties including physical properties, formation of ions and common reactions e.g. with oxygen to form oxides. C2.2b Be able to explain how the atomic structure of metals and non-metals relates to their position in the Periodic Table C2.2c 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 - reference to group number and period number. Atomic Structure - electronic structure Revision Notes Periodic Table Notes - an overview, groups, periods, metals & non-metals Revision Notes Extra Word-fill quiz "Atomic structure and elements" * Extra Word-fill quiz 2 "Atomic Structure" C2.2d Be able to explain how the reactions of elements are related to the arrangement of electrons in their atoms and hence to their atomic number. C2.2e Be able to explain in terms of atomic number how Mendeleev’s arrangement was refined into the modern Periodic Table Periodic Table Notes - an overview, groups, periods, metals & non-metals, history Revision Notes C2.2f Be able to describe and compare the nature and arrangement of chemical bonds in: (i) ionic compounds, (ii) simple molecules, (iii) giant covalent structures, (iv) polymers, (v) metals You should have make some ball and stick models of molecules. Introduction to Chemical Bonding Introduction to Types of Chemical Bonding and Materials Science Ionic compounds - structure and properties Revision Notes Covalent small simple molecules - structure and properties Revision Notes Macromolecules, giant covalent structures, polymers - structure and properties Notes Metals – structure and properties (including alloys) Revision Notes Addition polymer structure - properties and uses including poly(ethene) Revision Notes Some general 'bonding' word-fill quizzes Word-fill quiz "Metal Structure and Ionic Compounds" * Word-fill quiz "The structure and uses of different forms of carbon" Word-fill quiz "Simple Covalent Molecular Substances" Word-fill quiz "Molecular modelling and bonding diagrams of covalent molecules" C2.2g Be able to explain chemical bonding in terms of electrostatic forces and the transfer or sharing of electrons Introduction to Chemical Bonding and links above Revision Notes C2.2h Be able to construct dot and cross diagrams for simple covalent and binary ionic substances Ionic bonding and ionic compounds and their properties Revision Notes Covalent bonding and small molecules and their properties Revision Notes C2.2i Be able to describe the limitations of particular representations and models to include dot and cross diagrams, ball and stick models and two and three dimensional representations.
C2.3 Properties of materials (Revision for OCR Gateway Science GCSE 9-1 Combined Science A, 1st chemistry paper Topic C2 "Elements, compounds, mixtures", papers 3/9) This section explores the physical properties of elements and compounds and how the nature of their bonding is a factor in their properties. You should know the difference between an atom, element and compound. Common misconceptions - you have a limited understanding of chemical reactions, for example substances may explode, burn, contract, expand or change state. C2.3a Know that carbon can form four covalent bonds C2.3b Be able to explain that the vast array of natural and synthetic organic compounds occur due to the ability of carbon to form families of similar compounds, chains and rings. Introduction to Organic Chemistry - Why so many series of organic compounds? Revision Notes C2.3c Be able to explain the properties of diamond, graphite, fullerenes and graphene in terms of their structures and bonding. Covalent bonding and giant structures and their properties and uses Revision Notes Fullerenes; bucky balls and carbon nanotubes and Graphene Revision Notes C2.3d Be able to use ideas about energy transfers and the relative strength of chemical bonds and intermolecular forces to explain the different temperatures at which changes of state occur States of Matter - particle theory - gas, liquid & solid properties-behaviour, state changes Revision Notes
C2.3e Be able to use data to predict states of substances under given conditions using data such as temperature and how this may be linked to changes of state States of Matter - particle theory - gas, liquid & solid properties-behaviour, state changes Revision Notes C2.3f Be able to explain how the bulk properties of materials (ionic compounds; simple molecules; giant covalent structures; polymers and metals) are related to the different types of bonds they contain, their bond strengths in relation to intermolecular forces and the ways in which their bonds are arranged. You should recognise that the atoms themselves do not have the bulk properties of these materials Ionic bonding and ionic compounds and their properties Revision Notes Covalent bonding and small molecules and their properties Revision Notes Covalent bonding and giant structures and their properties and uses Revision Notes Metallic bonding, properties and uses of metals Revision Notes Polymer structure Revision Notes
Topic C3 Chemical reactions (Revision for OCR Gateway Science GCSE 9-1 Combined Science A, 1st chemistry paper Topic C3 "Chemical reactions", papers 3/9) OCR Gateway Science A GCSE 9-1 Combined Science A Topic C3 "Chemical Reactions" quiz content for chemistry 1: modelling chemical reactions, chemical symbols, chemical equations, law of conservation of mass, tests for gases, energetics - exothermic and endothermic calculations, types of chemical reactions, electrolysis of solutions with different electrodes, reactions of acids and bases, pH scale, salt preparations, (HT only) calculations using the Avogadro number, mole calculations, moles and mass conversions, bond energy calculations, oxidation and reduction theory of electrode half-equations, theory of weak and strong acids (higher tier HT/foundation tier FT)
for HT students
for FT students
HT = higher tier (harder - usually more theory & depth) and FT = foundation tier (easier) 1st drafts Gateway chemistry quizzes C3.1 Introducing chemical reactions (Revision for OCR Gateway Science GCSE 9-1 Combined Science A, 1st chemistry paper Topic C3 "Chemical reactions", papers 3/9) A chemical equation represents, in symbolic terms, the overall change in a chemical reaction. New materials are formed through chemical reactions but mass will be conserved. This can be explained by a model involving the rearrangement of atoms. Avogadro gave us a system of measuring the amount of a substance in moles. You should be familiar with chemical symbols and formulae for elements and compounds, representing chemical reactions using formulae and knowledge of conservation of mass, changes of state and chemical reactions. You may have to do calculations with numbers written in standard form when using the Avogadro and be able to convert units where appropriate particularly from mass to moles. Common misconceptions: Although you may have met the conservation of mass you may still tend to refer to chemical reactions as losing mass. Often you understand that mass is conserved but not the number or species of atoms. You may think that the original substance vanishes ‘completely and forever’ in a chemical reaction, not so! and the identity and number of atoms remains the same! but not in their original combinations! C3.1a Be able to use chemical symbols to write the formulae of elements and simple covalent and ionic compounds C3.1b Be able to use the names and symbols of common elements and compounds and the principle of conservation of mass to write formulae and balanced chemical equations and (HT only) half equations Calculating relative formula/molecular mass (Mr) of a compound or element molecule Revision Notes Type in answer quiz on relative formula mass Multiple Choice quiz on relative formula mass How to write word & balance symbol equations, work out formula and name compounds Revision Notes Law of Conservation of Mass and simple reacting mass calculations Type in answer quiz on the law of conservation of mass Multiple choice quiz on the law of conservation of mass C3.1c Be able to use the names and symbols of common elements from a supplied Periodic Table to write formulae and balanced chemical equations where appropriate including the first 20 elements, group 1, 7, and 0 and other common elements included within the specification. How to write word & symbol equations, work out formula and name compounds Revision Notes Element Symbol-name QUIZ easier-pictorial or harder-no pictures! Revision Notes Group 1 Alkali Metals - chemical properties Revision Notes Group 7 Halogens - chemical properties Revision Notes C3.1d Be able to use the formula of common ions to deduce the formula of a compound Ionic compounds section on working out formulae (section near end of page) Revision Notes C3.1e (HT only) Be able to construct balanced ionic equations How to write word & balance symbol equations, work out formula and name compounds Revision Notes C3.1f Be able to describe the physical states of products and reactants using state symbols (s, l, g and aq)
C3.1g Be able to describe tests to identify selected gases: oxygen, hydrogen, carbon dioxide and chlorine Summary of 'GCSE' tests for gases and ions including equations Revision Notes C3.1h (HT only) Know and be able to use the definitions of the Avogadro constant (in standard form) and of the mole including the calculation of the mass of one atom/molecule Introduction to moles type in answer QUIZ Introduction to moles multiple choice QUIZ C3.1i (HT only) Be able to explain how the mass of a given substance is related to the amount of that substance in moles and vice versa Introducing moles: The connection between moles, mass and formula mass Revision Notes Introduction to moles type in answer QUIZ Introduction to moles multiple choice QUIZ C3.1j (HT only) Be able to explain how the mass of a solute and the volume of the solution is related to the concentration of the solution. Concentration of solution in terms of mass and volume Revision Notes C3.1k Know and be able to use the law of conservation of mass. Law of Conservation of Mass and simple reacting mass calculations Revision Notes Type in answer quiz on the law of conservation of mass Multiple choice quiz on the law of conservation of mass Reacting mass ratio calculations of reactants and products from equations (NOT using moles) Type in answer QUIZ on reacting masses Multiple choice QUIZ on reacting masses Mole ratio calculations - equation interpretation and construction of balanced chemical equations C3.1l Be able to explain any observed changes in mass in non-enclosed systems during a chemical reaction and be able to explain them using the particle model Law of Conservation of Mass and simple reacting mass calculations Revision Notes Reacting mass ratio calculations of reactants and products from equations (NOT using moles) Type in answer QUIZ on reacting masses Multiple choice QUIZ on reacting masses C3.1m (HT only) Be able to deduce the stoichiometry of an equation from the masses of reactants and products and be able to explain the effect of a limiting quantity of a reactant. C3.1n (HT only) Be able to use a balanced equation to calculate masses of reactants or products. Reacting mass ratio calculations of reactants and products from equations (NOT using moles) The basis of reacting mole ratio calculations based on equations Revision Notes How much of a reactant is needed? calculation of quantities required, limiting quantities Revision Notes
C3.2 Energetics (Revision for OCR Gateway Science GCSE 9-1 Combined Science A, 1st chemistry paper Topic C3 "Chemical reactions", papers 3/9) Chemical reactions are accompanied by an energy change. A simple model involving the breaking and making of chemical bonds can be used to interpret and calculate the energy change. You should be familiar with exothermic and endothermic chemical reactions. Common misconceptions - energy is lost or used up rather than energy is transferred, thinking that energy is released when bonds break and do not link this release of energy with the formation of bonds and don't that eg a candle burning is endothermic because heat is needed to initiate the reaction. You are expected to be able to calculations involving energy changes. C3.2a Be able to distinguish between endothermic and exothermic reactions on the basis of the temperature change of the surroundings - practical measuring the temperature change in reactions. C3.2b Be able to draw and label a reaction profile for an exothermic and an endothermic reaction including activation energy, energy change, reactants and products. C3.2c Be able to explain activation energy as the energy needed for a reaction to occur. C3.2d (HT only) Be able to calculate energy changes in a chemical reaction by considering bond making and bond breaking energies Heat changes in chemical/physical changes - exothermic and endothermic Revision Notes Calorimeter methods of determining energy changes and examples of experiments you can do Activation energy and reaction profiles Revision Notes Introduction to bond energy/enthalpy calculations Revision Notes Energy transfer calculations from calorimeter results Revision Notes Multiple choice quiz on Energy Changes in Chemical Reactions
C3.3 Types of chemical reactions (Revision for OCR Gateway Science GCSE 9-1 Combined Science A, 1st chemistry paper Topic C3 "Chemical reactions", papers 3/9) Chemical reactions can be classified according to changes at the atomic and molecular level. Examples of these include reduction, oxidation and neutralisation reactions. You should be familiar with combustion, thermal decomposition, oxidation and displacement reactions. You should be familiar with defining acids and alkalis in terms of neutralisation reactions eg reactions of acids with alkalis to produce a salt and water and reactions of acids with metals to produce a salt and hydrogen. Common misconceptions - hydrogen ions in an acid are still part of the molecule, not free in the solution. pH is often misunderstood and alkalis are seen as less corrosive than acids. A big misconception is that the strength of acids and bases and concentration mean the same thing - they do NOT, so take care on these ideas. C3.3a Be able to explain reduction and oxidation in terms of loss or gain of oxygen, identifying which species are oxidised and which are reduced including the concept of oxidising agent and reducing agent. Introduction to oxidation and reduction and their application to redox reactions Revision Notes C3.3b (HT only) Be able to explain reduction and oxidation in terms of gain or loss of electrons, identifying which species are oxidised and which are reduced. Introduction to oxidation and reduction and their application to redox reactions Revision Notes C3.3c Know that acids form hydrogen ions when they dissolve in water and solutions of alkalis contain hydroxide ions. pH scale, indicator colours, ionic theory of acids, alkalis (bases) & neutralisation Revision Notes C3.3d Be able to describe neutralisation as acid reacting with alkali or a base to form a salt plus water.
Everyday examples of acid-alkali chemistry - examples and uses of acids and alkalis (pH quoted too) pH scale, indicator colours, ionic theory of acids, alkalis (bases) & neutralisation Revision Notes Making a soluble salt by neutralising a soluble acid with a soluble base (alkali) Revision Notes Making a soluble salt by from an acid with a metal or insoluble base – oxide, hydroxide or carbonate Notes C3.3e Recognise that aqueous neutralisation reactions can be generalised to hydrogen ions reacting with hydroxide ions to form water. pH scale, indicator colours, ionic theory of acids, alkalis (bases) & neutralisation Revision Notes C3.3f Know that carbonates and some metals react with acids and write balanced equations predicting products from given reactants. Reactions of acids with metals/oxides/hydroxides/carbonates and neutralisation reactions Revision Notes C3.3g (HT only) Be able to use and explain the terms dilute and concentrated (amount of substance) and weak and strong (degree of ionisation) in relation to acids - ratio of amount of acid to volume of solution. More on Acid-Base Theory and Weak and Strong Acids Revision Notes C3.3h Know that relative acidity and alkalinity are measured by pH pH scale, indicator colours, ionic theory of acids, alkalis (bases) & neutralisation Revision Notes C3.3i (HT only) Be able to describe neutrality and relative acidity and alkalinity in terms of the effect of the concentration of hydrogen ions on the numerical value of pH (whole numbers only) and pH of titration curves.
Changes in pH in a neutralisation reaction Revision Notes C3.3j (HT only) Know that as hydrogen ion concentration increases by a factor of ten the pH value of a solution decreases by one unit. C3.3k Be able to describe techniques and apparatus used to measure pH.
pH scale, indicator colours, ionic theory of acids, alkalis (bases) & neutralisation Revision Notes Word-fill quiz "The reactions of acids with oxides, hydroxides and carbonates" * Word-fill quiz "Methods of making salts" Word-fill quiz "Chemical tests for common gases" Word-fill quiz "Uses of some common compounds" Easy multiple choice quiz on "Acids, alkalis, salts and simple chemical reactions" (general questions on basic chemistry) Easy word-fill quizzes on "Acids and Alkalis" 7Ewf1 * 7Ewf2 * 7Ewf3 * 7Ewf4 Easy matching pair quiz on "pH"
C3.4 Electrolysis (Revision for OCR Gateway Science GCSE 9-1 Combined Science A, 1st chemistry paper Topic C3 "Chemical reactions", papers 3/9) Decomposition of a liquid during the conduction of electricity is a chemical reaction called electrolysis. This section explores the electrolysis of various molten ionic liquids and aqueous ionic solutions. You should be familiar with ionic solutions and solids. Common misconceptions - ionic solutions conduct because they are able to use of the movement of electrons. Another common misconception is that ionic solids do not conduct electricity because electrons cannot move. Introduction to electrolysis - electrolytes, non-electrolytes, electrode equations Revision Notes C3.4a Know that metals (or hydrogen) are formed at the cathode and non-metals are formed at the anode in electrolysis using inert electrodes and be familiar with the terms cations and anions Electrochemistry-Electrolysis Notes Index (lots of examples) Revision Notes Introduction to electrolysis - electrolytes, non-electrolytes, electrode equations Revision Notes Summary of electrode half-equations and products Revision Notes Summary of electrolysis products from various electrolytes Revision Notes Electrolysis of acidified water (dilute sulfuric acid) and some sulfate salts and alkalis Revision Notes C3.4b predict the products of electrolysis of binary ionic compounds in the molten state compounds such as NaCl. Electrolysis of molten lead(II) bromide (and other molten ionic compounds like NaCl) Revision Notes C3.4c Be able to describe competing reactions in the electrolysis of aqueous solutions of ionic compounds in terms of the different species present.
Electrolysis of sodium chloride solution (brine) Revision Notes Electrolysis of copper(II) sulfate solution Revision Notes C3.4d Be able to describe electrolysis in terms of the ions present and reactions at the electrodes Electrochemistry-Electrolysis Notes Index (lots of examples) Revision Notes C3.4e Be able to describe the technique of electrolysis using inert and non-inert electrodes. Electrolysis of copper(II) sulfate solution (inert or copper electrodes) and electroplating Revision Notes Test yourself with an Electrolysis Quiz (GCSE 9-1 HT Level (harder) Test yourself with an Electrolysis Quiz (GCSE 9-1 FT Level (easier)
CS7 Practical skills (Revision for OCR Gateway Science GCSE 9-1 Combined Science A, 1st chemistry paper Topic CS7 "Practical skills", papers 3/9)
ALL OCR GCSE (Grade 9-1) Level 1/Level 2 GATEWAY SCIENCE A specifications and syllabus revision summary links OCR (Grade 9-1) GCSE Gateway science BIOLOGY A 1st GCSE BIOLOGY paper (separate science Topics B1-3) OCR (Grade 9-1) GCSE Gateway science BIOLOGY A 2nd GCSE BIOLOGY paper (separate science Topics B4-6) OCR (Grade 9-1) GCSE Gateway science PHYSICS A 1st GCSE PHYSICS paper (separate science Topics P1-4) OCR (Grade 9-1) GCSE Gateway science PHYSICS A 2nd GCSE PHYSICS paper (separate science Topics P5-8) Watch out for HT Only sections AND make sure you know exactly which GCSE science course you are doing! See also OCR 21st Century Sciences B Revision Links
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INDEX
for all links
Topic
C1 "Particles"
QUIZ (OCR Gateway GCSE Chemistry-Combined Science)