Mini Chemistry updates
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- H1 Chemistry DefinitionsReference · H1 Chemistry
H1 Chemistry 8873 definitions by topic, including physical, inorganic and organic distinctions.
- H1 Chemistry Formula ListReference · H1 Chemistry
H1 Chemistry 8873 equations with units, assumptions, sign conventions and a worked calculation.
- H2 Chemistry DefinitionsReference · H2 Chemistry
H2 Chemistry 9476 definitions by topic, including physical, inorganic and organic distinctions.
- H2 Chemistry Formula ListReference · H2 Chemistry
H2 Chemistry 9476 equations with units, assumptions, sign conventions and a worked calculation.
- H3 Chemistry DefinitionsReference · H3 Chemistry
H3 Chemistry 9813 definitions for spectroscopy, molecular stereochemistry and organic mechanisms, with H2 foundations.
- H3 Chemistry Formula ListReference · H3 Chemistry
H3 Chemistry 9813 spectroscopy, stereochemistry and rate-law relationships with units, conditions and H2 foundations.
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- G2 Science Chemistry DefinitionsReference · G2 Science (Chemistry)
G2 Science Chemistry terms by topic, with precise particle meanings and distinctions for recall and explanation.
- G2 Science Chemistry Formula ListReference · G2 Science (Chemistry)
G2 Science Chemistry calculation relationships with units, reacting ratios, worked examples and the correct course scope.
- Acids, Bases & SaltsHub · G3 Pure Chemistry / O-Level Chemistry
Acids, bases and salts hub: aqueous ions, pH, core reactions, solubility rules, salt preparation, ammonia and exam practice.
- Introduction to AcidsLesson · G3 Pure Chemistry / O-Level Chemistry
Acids: aqueous hydrogen ions, complete versus partial ionisation, and the distinction between acid strength and concentration.
- Acid-Base Chemistry · G3 Pure and O-Level ChemistryPractice · G3 Pure Chemistry / O-Level Chemistry
Check what you know about G3 Pure Chemistry Acid-Base Chemistry, practise what needs work, then check your progress and come back for a later review.
- Introduction to BasesLesson · G3 Pure Chemistry / O-Level Chemistry
Bases and alkalis: definitions, aqueous hydroxide ions, neutralisation and the ammonium-ion reaction.
- Manufacturing Ammonia (Haber Process)Lesson · G3 Pure Chemistry / O-Level Chemistry
Haber process: feedstocks, reversible equation, ammonia separation, gas recycling and interpretation of supplied industrial data.
- OxidesLesson · G3 Pure Chemistry / O-Level Chemistry
Oxides: classify acidic/basic/amphoteric/neutral, and write the key reactions and equations examiners expect.
- pH Scale & IndicatorsLesson · G3 Pure Chemistry / O-Level Chemistry
pH scale & indicators: acidic/neutral/alkaline ranges, key colour changes (litmus/universal indicator), and how to answer exam-style questions.
- Physical & Chemical Properties of AcidsLesson · G3 Pure Chemistry / O-Level Chemistry
Acid properties and reactions: indicator behaviour, and the 3 core reactions with metals, bases and carbonates—plus key observations and gas tests.
- Physical & Chemical Properties of AlkalisLesson · G3 Pure Chemistry / O-Level Chemistry
Alkali properties and reactions: pH > 7 and red litmus → blue, neutralisation, ammonium salts test (ammonia), and precipitate formation.
- Preparing Insoluble SaltsLesson · G3 Pure Chemistry / O-Level Chemistry
Prepare an insoluble salt by precipitation: choose soluble ion sources, collect the residue, wash away dissolved impurities and dry the product.
- Preparing Soluble SaltsLesson · G3 Pure Chemistry / O-Level Chemistry
Prepare soluble salts using excess insoluble solid or titration, then separate and crystallise the product. Explain how each step protects purity.
- Ammonia and Ammonium SaltsLesson · G3 Pure Chemistry / O-Level Chemistry
Ammonia and ammonium ions: the damp-red-litmus gas test, the ammonium-ion test and the balanced ionic equations.
- SaltsLesson · G3 Pure Chemistry / O-Level Chemistry
Salts: definitions, formulae, solubility rules, precipitate prediction and selecting excess-solid, titration or precipitation methods.
- Sulfur Dioxide and Sulfuric AcidLesson · G3 Pure Chemistry / O-Level Chemistry
Sulfur dioxide: its acidified potassium manganate(VII) test, acid-rain effects, flue-gas removal and dilute sulfuric acid links.
- Stoichiometry & The Mole ConceptHub · G3 Pure Chemistry / O-Level Chemistry
Chemistry stoichiometry hub: formulas, balanced equations, mole calculations, concentration, limiting reagent, and yield/purity. Practise the topic with its check.
- Relative atomic, molecular and formula massLesson · G3 Pure Chemistry / O-Level Chemistry
Ar and Mr (formula mass): understand the carbon-12 comparison and calculate relative masses accurately using subscripts and brackets.
- Chemical Calculations · G3 Pure and O-Level ChemistryPractice · G3 Pure Chemistry / O-Level Chemistry
Check what you know about G3 Pure Chemistry Chemical Calculations, practise what needs work, then check your progress and come back for a later review.
- Finding empirical and molecular formulaeLesson · G3 Pure Chemistry / O-Level Chemistry
Empirical and molecular formula: find simplest whole-number ratios from mass/% data, then use Mr to get the molecular formula.
- Writing and balancing chemical equationsLesson · G3 Pure Chemistry / O-Level Chemistry
Chemical equations: write reactants → products, balance using coefficients, and add state symbols (s/l/g/aq) without changing subscripts.
- Writing chemical symbols and formulaeLesson · G3 Pure Chemistry / O-Level Chemistry
Read chemical notation, balance ion charges and use brackets correctly. Distinguish simplest atom ratios from the actual atoms in a molecule.
- Writing ionic equationsLesson · G3 Pure Chemistry / O-Level Chemistry
Ionic equations: split aqueous ions, cancel spectator ions, and balance atoms and charge for common precipitation, neutralisation, and gas reactions.
- Limiting reactants and excess left overLesson · G3 Pure Chemistry / O-Level Chemistry
Limiting reactant: identify what runs out first using moles and the balanced equation, then calculate theoretical yield and excess left.
- Gas volumes and reacting amountsLesson · G3 Pure Chemistry / O-Level Chemistry
Convert gas volumes into moles at room temperature and pressure, then use a balanced equation to calculate reacting masses and gas volumes.
- Moles, molar mass and particle countsLesson · G3 Pure Chemistry / O-Level Chemistry
Use the mole to connect mass and particle counts. Choose the correct entity and molar mass, keep units consistent and round the final answer.
- Percentage composition by massLesson · G3 Pure Chemistry / O-Level Chemistry
Percentage composition by mass: calculate the element contribution, divide by the compound's total relative mass, then multiply by 100.
- Percentage purity: finding the pure partLesson · G3 Pure Chemistry / O-Level Chemistry
Find the pure substance in an impure sample from gas or titration data, calculate percentage purity, and combine purity with percentage yield.
- Percentage yield: actual versus theoreticalLesson · G3 Pure Chemistry / O-Level Chemistry
Calculate percentage yield from actual and theoretical amounts, distinguish it from purity, and explain low or apparently excessive experimental yields.
- Solution concentration and titration calculationsLesson · G3 Pure Chemistry / O-Level Chemistry
Use mass and molar concentration, conserve solute amount during dilution, and calculate an unknown concentration from a titration and its balanced equation.
- Energy Changes in Chemical ReactionsHub · G3 Pure Chemistry / O-Level Chemistry
K324 and 6092 energy changes hub: enthalpy, energy profiles, and qualitative bond-breaking and bond-making explanations.
- Hydrogen as a Fuel and Fuel CellsLesson · G3 Pure Chemistry / O-Level Chemistry
Learn why hydrogen is a potential fuel, how a hydrogen fuel cell generates electricity directly, and how production affects its environmental impact.
- Bond Breaking and Bond FormingLesson · G3 Pure Chemistry / O-Level Chemistry
Explain qualitatively why reactions are exothermic or endothermic by comparing energy absorbed in bond breaking with energy released in bond making.
- Calculating Heat from Molar Enthalpy (Optional)Lesson · G3 Pure Chemistry / O-Level Chemistry
Optional enrichment: scale a supplied molar enthalpy, distinguish signed heat from energy released, and use the balanced equation’s reacting amount.
- Chemical Energetics · G3 Pure and O-Level ChemistryPractice · G3 Pure Chemistry / O-Level Chemistry
Check what you know about G3 Pure Chemistry Chemical Energetics, practise what needs work, then check your progress and come back for a later review.
- Endothermic ReactionsLesson · G3 Pure Chemistry / O-Level Chemistry
Endothermic reactions: definition, ΔH is positive, and how to interpret energy profile diagrams and activation energy in exam questions.
- Exothermic ReactionsLesson · G3 Pure Chemistry / O-Level Chemistry
Exothermic reactions: definition, ΔH is negative, and how to interpret energy profile diagrams and activation energy without common traps.
- Fossil Fuels: Combustion and EmissionsLesson · G3 Pure Chemistry / O-Level Chemistry
Explain non-renewable fossil fuels, balance methane combustion, and connect oxygen supply and fuel composition to emissions.
- Introduction to Energy ChangesLesson · G3 Pure Chemistry / O-Level Chemistry
Follow heat between the reacting system and its surroundings, distinguish exothermic and endothermic changes, and use the sign of ΔH.
- Reading and Drawing Energy ProfilesLesson · G3 Pure Chemistry / O-Level Chemistry
Read and draw exothermic and endothermic profiles, distinguish activation energy from enthalpy change, and add a catalysed pathway with the same endpoints.
- G3 Pure and O-Level Chemistry DefinitionsReference · G3 Pure Chemistry / O-Level Chemistry
G3 Pure and O-Level Chemistry terms by topic, with precise particle meanings and distinctions for recall and explanation.
- G3 Pure and O-Level Chemistry Formula ListReference · G3 Pure Chemistry / O-Level Chemistry
G3 Pure and O-Level Chemistry calculation relationships with units, reacting ratios, worked examples and the correct course scope.
- Environmental ChemistryHub · G3 Pure Chemistry / O-Level Chemistry
Chemistry environmental hub: air composition and pollutants, acid rain, greenhouse gases, global warming, and ozone depletion. Practise the topic with its check.
- Acid Rain Chemistry and ControlLesson · G3 Pure Chemistry / O-Level Chemistry
Explain how sulfur dioxide and nitrogen oxides form acid rain, its effects, and how source controls interrupt the chain.
- Air Composition and EvidenceLesson · G3 Pure Chemistry / O-Level Chemistry
Interpret evidence for the approximate composition of clean, dry air and distinguish normal components from pollutants.
- Air Pollutants: Sources, Effects and ControlsLesson · G3 Pure Chemistry / O-Level Chemistry
Link prescribed air pollutants to specific sources, harmful effects and targeted emission controls.
- Carbon CycleLesson · G3 Pure Chemistry / O-Level Chemistry
Trace carbon transfers between atmospheric carbon dioxide, living material and fuels.
- Maintaining Air Quality · G3 Pure and O-Level ChemistryPractice · G3 Pure Chemistry / O-Level Chemistry
Check what you know about G3 Pure Chemistry Maintaining Air Quality, practise what needs work, then check your progress and come back for a later review.
- Greenhouse Effect, Climate and MitigationLesson · G3 Pure Chemistry / O-Level Chemistry
Use atmospheric evidence to explain infrared heat trapping, climate consequences and mitigation choices.
- Ozone Layer and DepletionLesson · G3 Pure Chemistry / O-Level Chemistry
Explain how stratospheric ozone protects life, how CFCs deplete it and why ultraviolet exposure increases.
- Simple and fractional distillationLesson · G3 Pure Chemistry / O-Level Chemistry
Recover a solvent or separate miscible liquids by vaporisation, condensation and repeated enrichment in a fractionating column.
- Choosing a drying agent for a gasLesson · G3 Pure Chemistry / O-Level Chemistry
Remove water vapour without removing the gas: compare calcium oxide, concentrated sulfuric acid and fused calcium chloride.
- Paper chromatography and Rf valuesLesson · G3 Pure Chemistry / O-Level Chemistry
Set up paper chromatography, compare unknown and reference spots, calculate Rf and explain the limits of the evidence.
- Why alloys have different propertiesLesson · G3 Pure Chemistry / O-Level Chemistry
Identify alloys from composition and particle diagrams, explain how different-sized particles hinder layer movement, and distinguish hardness from other material properties.
- Atomic structure and particle countsLesson · G3 Pure Chemistry / O-Level Chemistry
Describe the nucleus and electron shells, compare subatomic particles, and count protons, neutrons and electrons in atoms and single-atom ions.
- Comparing covalent structuresLesson · G3 Pure Chemistry / O-Level Chemistry
Compare small molecules, poly(ethene) chains and giant covalent networks. Use bonds, forces and mobile charge carriers to explain their properties.
- Covalent bonding and electron diagramsLesson · G3 Pure Chemistry / O-Level Chemistry
Count shared and lone electron pairs, draw dot-and-cross diagrams, and deduce single, double and triple covalent bonds.
- DiffusionLesson · G3 Pure Chemistry / O-Level Chemistry
Diffusion: net movement from high to low concentration, particle explanation, and factors affecting speed (temperature, state, molecular mass).
- Electron configurationLesson · G3 Pure Chemistry / O-Level Chemistry
Arrange electrons in shells for the first 20 elements, identify valence electrons and use neutral-atom arrangements to find group and period.
- Elements, compounds and mixturesLesson · G3 Pure Chemistry / O-Level Chemistry
Classify elements, compounds and mixtures using atom identity, chemical combination and composition, and explain why alloys remain mixtures.
- Elements and isotopesLesson · G3 Pure Chemistry / O-Level Chemistry
Read nuclide notation, distinguish isotopes by proton and neutron counts, and explain why shared electron arrangements give very similar chemistry.
- Ionic bonding: forming ions and balancing chargesLesson · G3 Pure Chemistry / O-Level Chemistry
Form ions by electron loss and gain, show sodium chloride and magnesium chloride with dot-and-cross diagrams, and balance charges to write formulas.
- Ionic structures and propertiesLesson · G3 Pure Chemistry / O-Level Chemistry
Use the giant lattice and ion mobility to explain high melting temperatures and the electrical conductivity of solid, molten and dissolved ionic compounds.
- Kinetic particle theoryLesson · G3 Pure Chemistry / O-Level Chemistry
Use Kinetic Particle Theory to explain solids, liquids, gases, changes of state and diffusion through particle arrangement, motion and energy.
- Giant covalent structures: diamond, graphite and silicaLesson · G3 Pure Chemistry / O-Level Chemistry
Explain the hardness, conductivity and heat resistance of diamond, graphite and silicon dioxide using their giant covalent structures.
- Metallic bonding and metal propertiesLesson · G3 Pure Chemistry / O-Level Chemistry
Use positive metal ions and delocalised electrons to explain electrical and thermal conduction, melting behaviour, malleability and ductility.
- Molecular structures and propertiesLesson · G3 Pure Chemistry / O-Level Chemistry
Distinguish bonds within molecules from attractions between molecules, and use structure to explain melting, boiling and electrical behaviour.
- The Particulate Nature of Matter · G3 Pure and O-Level ChemistryPractice · G3 Pure Chemistry / O-Level Chemistry
Check what you know about G3 Pure Chemistry The Particulate Nature of Matter, practise what needs work, then check your progress and come back for a later review.
- What is matter?Lesson · G3 Pure Chemistry / O-Level Chemistry
Matter: made of atoms, molecules or ions, and the particle-model properties of solids, liquids and gases (shape, volume, compressibility).
- Organic ChemistryHub · G3 Pure Chemistry / O-Level Chemistry
Organic hub: functional groups, fuels, alkanes and alkenes, alcohols, carboxylic acids, esters and polymers. Practise the topic with its check.
- Alcohol Structures and IsomersLesson · G3 Pure Chemistry / O-Level Chemistry
Draw and name C1–C4 alcohols, distinguish molecular and grouped formulae, and recognise changes in branching and hydroxyl-group position.
- Alkane ReactionsLesson · G3 Pure Chemistry / O-Level Chemistry
Explain methane combustion and UV chlorine substitution, balance combustion equations, and use products to identify incomplete combustion.
- Alkane Structures and IsomersLesson · G3 Pure Chemistry / O-Level Chemistry
Draw and name the C1–C4 alkanes, use their general formula, explain physical trends, and distinguish the two C4 structural isomers.
- Addition Reactions of AlkenesLesson · G3 Pure Chemistry / O-Level Chemistry
Follow ethene through hydrogenation, bromination, hydration and polymerisation, and explain hydrogenation of vegetable oils.
- Alkene Structures and the Bromine TestLesson · G3 Pure Chemistry / O-Level Chemistry
Draw C2–C4 alkene structures, distinguish structural isomers, and use bromine-water observations to identify unsaturation.
- Biofuels and Carbon EmissionsLesson · G3 Pure Chemistry / O-Level Chemistry
Explain sugarcane bioethanol as a renewable fuel, follow carbon through its production and combustion, and evaluate emissions across its life cycle.
- Carboxylic Acid Structures and ReactionsLesson · G3 Pure Chemistry / O-Level Chemistry
Draw and name C1–C4 carboxylic acids, explain partial ionisation, and predict reactions with metals, bases and carbonates.
- Condensation PolymersLesson · G3 Pure Chemistry / O-Level Chemistry
Recognise nylon and Terylene from partial chains, distinguish amide and ester linkages, and connect man-made fibres to their uses.
- Cracking and Refinery DemandLesson · G3 Pure Chemistry / O-Level Chemistry
Explain why refineries crack hydrocarbons, describe the conditions, and use atom conservation to deduce products.
- Esters: Formation and NamingLesson · G3 Pure Chemistry / O-Level Chemistry
Locate the ester linkage, form an ester from a C1–C4 alcohol and carboxylic acid, and work backwards from its name or structure.
- Ethanol ProductionLesson · G3 Pure Chemistry / O-Level Chemistry
Compare fermentation of glucose with hydration of ethene, explain their conditions, and choose a route using stated production priorities.
- Ethanol Reactions and OxidationLesson · G3 Pure Chemistry / O-Level Chemistry
Distinguish ethanol combustion from oxidation to ethanoic acid, conserve oxygen atoms, and interpret acidified manganate(VII) observations.
- Crude Oil and Fractional DistillationLesson · G3 Pure Chemistry / O-Level Chemistry
Explain why natural gas and crude oil are non-renewable, how fractional distillation separates crude oil, and how fraction properties determine their uses.
- Interpreting Crude-Oil FractionsLesson · G3 Pure Chemistry / O-Level Chemistry
Use boiling ranges, column conditions and material properties to explain crude-oil fractions and choose suitable uses.
- Introduction to Organic ChemistryLesson · G3 Pure Chemistry / O-Level Chemistry
Organic chemistry basics: homologous series, functional groups, general formulas, and how saturation/unsaturation links to reactions and tests.
- Plastic Waste and RecyclingLesson · G3 Pure Chemistry / O-Level Chemistry
Explain plastic disposal problems, distinguish physical and chemical recycling, and weigh social, economic and environmental trade-offs.
- Addition PolymersLesson · G3 Pure Chemistry / O-Level Chemistry
Read repeat units, preserve atoms and substituents, and deduce alkene monomers from their addition polymers.
- Patterns in the Periodic Table · G3 Pure and O-Level ChemistryPractice · G3 Pure Chemistry / O-Level Chemistry
Check what you know about G3 Pure Chemistry Patterns in the Periodic Table, practise what needs work, then check your progress and come back for a later review.
- Metal Extraction and Compound StabilityLesson · G3 Pure Chemistry / O-Level Chemistry
Explain metal-oxide reduction, the effects of heating carbonates and how reactivity affects metal extraction.
- Metals and Non-MetalsLesson · G3 Pure Chemistry / O-Level Chemistry
Compare metals and non-metals, link outer electrons to ion formation, and apply the metallic-to-non-metallic trend across a period.
- The Reactivity Series of MetalsLesson · G3 Pure Chemistry / O-Level Chemistry
Use water, steam, dilute-acid and displacement observations to compare metals and explain electron transfer.
- Rusting and Protecting IronLesson · G3 Pure Chemistry / O-Level Chemistry
Use controlled rusting evidence to explain barriers, galvanising and sacrificial protection with magnesium.