England · OCRSyllabus
Chemistry syllabus, dot point by dot point
Every dot point in the England Chemistrysyllabus, with a focused answer for each one. Click any dot point for a worked explainer, past exam questions, and links to related dot points. Written by Claude Opus 4.8, Anthropic's latest AI.
C3 Chemical reactions
Module overview →- How does electrolysis split compounds, and what is made at each electrode?Electrolysis of molten and aqueous compounds, the movement of ions to the electrodes, predicting the products at the cathode and anode, half equations at the electrodes, and the extraction of reactive metals.10 min answer →
- Why do some reactions give out heat and others take it in, and how do we show this on an energy diagram?Exothermic and endothermic reactions and their uses, reaction profiles, activation energy, and calculating the overall energy change from bond energies.9 min answer →
- How do we represent chemical reactions with equations, and why is mass always conserved?Word and balanced symbol equations, conservation of mass, balancing equations, ionic equations, and explaining apparent mass changes in open systems.9 min answer →
- What do oxidation and reduction mean, in terms of both oxygen and electrons?Oxidation and reduction in terms of oxygen and electrons, redox reactions, oxidising and reducing agents, and writing half equations for the loss and gain of electrons.8 min answer →
- What is the mole, and how do we use it to calculate reacting masses?Relative formula mass, the mole and the Avogadro constant, calculating moles from mass, using mole ratios to find reacting masses, limiting reactants, and percentage yield.10 min answer →
- How do acids react with metals, bases and carbonates, and what does the pH scale tell us?The reactions of acids with metals, bases and carbonates, neutralisation, salts, the pH scale, strong and weak acids, and making soluble salts.9 min answer →
C2 Elements, compounds and mixtures
Module overview →- How do non-metals share electrons to form covalent bonds, and what structures can result?Covalent bonding as shared pairs of electrons between non-metals, dot and cross diagrams for simple molecules, simple molecular substances, and giant covalent structures such as diamond, graphite and silicon dioxide.9 min answer →
- How do metals and non-metals transfer electrons to form ionic bonds, and what holds an ionic compound together?Ionic bonding as the transfer of electrons between metals and non-metals, the formation of positive and negative ions, dot and cross diagrams, ionic formulae, and the giant ionic lattice.9 min answer →
- What is metallic bonding, and how does it explain the properties of metals and alloys?Metallic bonding as a lattice of positive ions in a sea of delocalised electrons, the link to the properties of metals (conduction, malleability, high melting points), and why alloys are harder than pure metals.8 min answer →
- What are nanoparticles, why does size matter so much, and how do we represent the states of substances?Nanoparticles, coarse and fine particles, the high surface area to volume ratio of nanoparticles and its consequences, uses and risks of nanoparticles, and the state symbols used in equations.8 min answer →
- What is the difference between a pure substance and a mixture, and how can mixtures be separated?Pure substances, mixtures and formulations, and the techniques for separating mixtures: filtration, crystallisation, simple and fractional distillation, and paper chromatography with Rf values.9 min answer →
- How are the bonding and structure of a substance related to its properties?Relating bonding and structure to the properties of substances: melting and boiling points, electrical conductivity and state, across ionic, simple molecular, giant covalent and metallic substances, and the limitations of bonding models.9 min answer →
C6 Global challenges
Module overview →- Which pollutants form when fuels burn, and what harm do they do?Complete and incomplete combustion of fuels, the formation of carbon dioxide, carbon monoxide, sulfur dioxide, oxides of nitrogen and particulates, and the effects of these pollutants.9 min answer →
- What is crude oil, how is it separated into useful fractions, and why is it cracked?Crude oil as a mixture of hydrocarbons, alkanes and their general formula, the fractional distillation of crude oil, the uses of the fractions, and the cracking of long-chain hydrocarbons.10 min answer →
- How is ammonia made in industry, and why are the conditions of the Haber process a compromise?The Haber process for making ammonia, the compromise conditions of temperature and pressure, the use of an iron catalyst and recycling, and the use and importance of NPK fertilisers.10 min answer →
- How do we judge the environmental impact of a product over its whole life, and why do we recycle materials?Life cycle assessment (LCA) and its stages, the limitations of LCAs, and the advantages and disadvantages of recycling and reusing materials including metals.9 min answer →
- What is the atmosphere made of, how did it evolve, and how do greenhouse gases drive climate change?The composition of the atmosphere, how it evolved over time, the greenhouse gases and the greenhouse effect, and the link between human activity, climate change and the carbon footprint.10 min answer →
- How do we make safe drinking water, treat waste water, and extract metals sustainably?Producing potable water by sedimentation, filtration and sterilisation, desalination by distillation and reverse osmosis, treating waste water, and the sustainable extraction of metals by phytomining and bioleaching.10 min answer →
C5 Monitoring and controlling chemical reactions
Module overview →- How do catalysts speed up reactions, and how are reactions controlled in industry?Catalysts and how they lower the activation energy, enzymes as biological catalysts, the effect of catalysts on reaction profiles, and how conditions are controlled to manage rate and yield.8 min answer →
- How do we measure concentration, and how does a titration find the concentration of an acid or alkali?Concentration in grams and moles per cubic decimetre, calculating concentration, the method and apparatus of a titration, and calculating an unknown concentration from titration results.10 min answer →
- How do we measure the rate of a reaction and read rates from a graph?Methods for following the rate of a reaction, calculating mean rate from quantity and time, drawing and interpreting rate graphs, and finding the rate at a given moment using a tangent.9 min answer →
- What controls how fast a reaction goes, and how does collision theory explain it?Collision theory, the factors affecting the rate of reaction (concentration, pressure, surface area, temperature and catalysts), and explaining each factor in terms of the frequency and energy of collisions.9 min answer →
- What is a reversible reaction, and how does an equilibrium respond to changing conditions?Reversible reactions, dynamic equilibrium in a closed system, the energy changes in the two directions, and Le Chatelier's principle applied to changes in concentration, temperature and pressure.9 min answer →
C1 Particles
Module overview →- What is inside an atom, and what do the atomic number and mass number tell us?The sub-atomic particles and their relative masses and charges, the nucleus and electrons, atomic number and mass number, isotopes, relative atomic mass, and the size and scale of atoms.9 min answer →
- How did the model of the atom change as new experimental evidence was gathered?The historical development of the atomic model from Dalton to the nuclear model, including the plum pudding model, the alpha particle scattering experiment, the discovery of the nucleus, Bohr's shells, and the discovery of the neutron.8 min answer →
- How are electrons arranged in atoms, and how does this link to the periodic table?The arrangement of electrons in shells (energy levels), writing electronic configurations for the first 20 elements, and the link between the number of outer-shell electrons and an element's group and chemical behaviour.8 min answer →
- How does the particle model explain the three states of matter and changes of state?The particle model, the three states of matter, changes of state, the energy and arrangement of particles in solids, liquids and gases, and the limitations of the simple model.9 min answer →
- How is the periodic table organised, and how do the properties of Group 1, Group 7 and Group 0 change down the group?The structure of the periodic table, the work of Mendeleev, metals and non-metals, and the trends in reactivity and properties of Group 1 (alkali metals), Group 7 (halogens) and Group 0 (noble gases).9 min answer →
C4 Predicting and identifying reactions and products
Module overview →- How do chromatography and instrumental methods identify substances, and why are instruments so useful?Paper chromatography and Rf values applied to identifying substances, the advantages of instrumental methods of analysis, and using flame emission spectroscopy to identify and measure metal ions.8 min answer →
- How are metals extracted from their ores, and how does the method depend on reactivity?Metal ores and oxidation, extracting metals by reduction with carbon, extracting reactive metals by electrolysis, the position of carbon in the reactivity series, and predicting reactions of Group 1 and Group 7 elements.9 min answer →
- How can we identify carbonate, halide and sulfate ions in a sample?Tests for negative ions (anions): the carbonate test with acid, the halide test with silver nitrate, and the sulfate test with barium chloride, including the observations and ionic equations.8 min answer →
- How can we identify metal ions and common gases by chemical tests?Flame tests for metal ions, the use of sodium hydroxide to identify metal ions by precipitate colour, and the tests for hydrogen, oxygen, carbon dioxide, chlorine and ammonia.9 min answer →
- How does the reactivity series let us predict the reactions of metals?The reactivity series of metals, the reactions of metals with water, oxygen and acids, displacement reactions, and using the reactivity series to predict reactions.9 min answer →