AQA GCSE Chemistry

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Papers 1 and 2 (fundamental concepts)

4.1 - Atomic structure and the periodic table

4.1.1.1 - Atoms, elements, compounds and equationsLearn how atoms distinguish elements, how chemical formulae describe compounds, and how equations represent reactions. These ideas let you read a chemical name, identify the particles involved and check that an equation accounts for every atom.
4.1.1.2 - Separating mixturesLearn why mixtures can be separated without chemical reactions and how filtration, crystallisation, distillation and chromatography work. Choosing a method means using a difference in physical properties while keeping the substance you want.
4.1.1.3 - How the atomic model developedLearn how experimental evidence changed the model of the atom from an indivisible sphere to a tiny nucleus surrounded by electrons. Comparing a model's predictions with observations explains why scientists keep useful ideas but replace parts that no longer fit the evidence.
4.1.1.4,4.1.1.5 - Subatomic particles, isotopes and atomic scaleUse the nuclear model to explain atomic charge, count particles in atoms and ions, and distinguish isotopes. Comparing particle charges, masses and sizes shows why almost all atomic mass occupies a tiny part of an atom's volume.
4.1.1.6,4.1.1.7 - Relative atomic mass and electronic structureCalculate relative atomic mass from isotope abundances, then build electronic structures for the first twenty elements. Connect the average mass printed in the periodic table with isotope populations and the table's chemical patterns with electron arrangements.
4.1.2.1,4.1.2.2,4.1.2.3 - The periodic table and its developmentConnect an element's position in the periodic table to its electrons and chemical behaviour. Learn how evidence shaped earlier tables and why the modern arrangement helps predict the behaviour of metals and non-metals.
4.1.2.4,4.1.2.5 - Group 0 and Group 1Compare the stable electron arrangements of Group 0 with the reactive metals of Group 1. Explain noble-gas boiling-point trends, alkali-metal reactions and the increasing ease of losing an outer electron down Group 1.
4.1.2.6 - Halogens and displacementLearn how the seven outer electrons of Group 7 account for similar compounds and a decreasing reactivity trend. Compare chlorine, bromine and iodine, then use displacement reactions and colour evidence to decide which halogen is more reactive.
4.1.3.1,4.1.3.2 - Transition metals and their compoundsCompare the transition metals with Group 1, using chromium, manganese, iron, cobalt, nickel and copper as examples. Connect their physical properties, reactivity, variable ion charges and coloured compounds to practical uses, including catalysis.

4.2 - Bonding, structure and properties of matter

4.2.1.1,4.2.1.2,4.2.1.3,4.2.2.3 - Ionic bonding and ionic compoundsLearn how electron transfer produces ions, how the attraction between those ions builds a giant structure, and how to represent that structure. You will use ion charges and diagrams to find formulae and explain why an ionic compound can conduct electricity in some states but not others.
4.2.1.1,4.2.1.4 - Covalent bonding and representationsLearn how non-metal atoms share electrons to form covalent bonds and how to draw the required molecules. You will read molecular formulae, displayed structures and models, then distinguish small molecules, polymer chains and giant covalent networks without treating a drawing as a literal picture...
4.2.1.5,4.2.2.7,4.2.2.8 - Metallic bonding, metals and alloysLearn how a metal's giant structure and delocalised electrons explain strong bonding, electrical and thermal conduction, and the ability to bend. You will compare a pure metal with an alloy and use the arrangement of its atoms to explain why mixing elements can make a useful harder material.
4.2.2.1,4.2.2.2 - States of matter and changes of stateLearn how particle arrangement, motion and attractions explain solids, liquids, gases and changes of state. Use melting and boiling data to predict a substance's state, add state symbols to equations, and recognise what a simple particle picture leaves out.
4.2.2.4,4.2.2.5 - Small molecules and polymersLearn why strong covalent bonds inside a molecule can coexist with a low boiling point, and why increasing molecular size changes physical properties. You will compare small molecules with very large polymer molecules and explain their states and electrical behaviour from the particles and forces...
4.2.2.6,4.2.3.1,4.2.3.2 - Giant covalent structures, diamond and graphiteLearn how an extended network of covalent bonds differs from a substance made of separate molecules. You will compare silicon dioxide, diamond and graphite, then use carbon's bonding, layers and delocalised electrons to explain hardness, high melting points and electrical conduction.
4.2.3.3 - Graphene, fullerenes and nanotubesLearn how a single carbon sheet, a hollow carbon cage and a carbon tube differ in shape and bonding. You will recognise graphene and fullerenes from representations and connect their strength, electron behaviour and dimensions to possible uses in electronics, composites and nanotechnology.
4.2.4.1,4.2.4.2 - Nanoparticles, surface area and applicationsLearn how nanoscale dimensions compare with atoms and larger particles, and calculate why small particles have a high surface-area-to-volume ratio. You will use that relationship to explain potential applications, then evaluate supplied evidence about benefits and possible risks without assuming...

4.3 - Quantitative chemistry

4.3.1.1,4.3.1.2,4.3.1.3 - Conservation of mass and formula calculationsLearn why chemical equations must conserve atoms, how formulae give relative formula masses and percentage composition, and why a balance can appear to show a mass change when a gas enters or leaves a reaction. These ideas connect the particle model to quantities that can be measured in a laborat...
4.3.1.4 - Chemical measurements and uncertaintyLearn why every chemical measurement has uncertainty and how repeated results, their mean and their spread help describe it. Distinguish random variation from consistent bias, then use that distinction to choose improvements that make evidence more useful.
4.3.2.1 - Moles, masses and particle numbersLearn how chemists count very large numbers of particles using moles, convert between mass and amount of substance, and distinguish molecules from the atoms or ions they contain. These counting methods connect laboratory quantities with the particles taking part in reactions.
4.3.2.2 - Reacting masses from equationsLearn how the coefficients of a balanced chemical equation give mole ratios, and use those ratios to calculate masses of reactants and products in either direction. Substances react in fixed particle proportions even though their required masses may be very different.
4.3.2.3,4.3.2.4 - Balancing from masses and limiting reactantsLearn how measured masses can reveal an equation's whole-number coefficients, then use the resulting mole ratios to decide which reactant limits product formation. Link balancing from data with maximum-product and excess-reactant calculations.
4.3.2.5 - Mass concentration of solutionsLearn how concentration describes the mass of solute in a given volume of solution, how to convert volume units, and how to calculate the solute mass in a sample. Connect this ratio with the effects of changing solute mass or adding solvent.
4.3.3.1,4.3.3.2 - Percentage yield and atom economyLearn why a reaction may yield less product than its calculated maximum, how to calculate percentage yield, and how atom economy measures the use of starting materials. Distinguish losses during production from atoms going into unwanted products, then use reaction data to compare manufacturing ro...
4.3.4 - Molar concentration and titration calculationsLearn how concentration in moles per cubic decimetre relates to solute amount, mass and solution volume. Use measured titration volumes, a known concentration and a balanced equation to calculate an unknown concentration.
4.3.5 - Gas volumes at room temperature and pressureLearn how gas volume is related to amount in moles, use the molar gas volume at room temperature and pressure, and calculate reacting gas volumes from balanced equations. Connect a measured gas volume with the mass of a gas or a solid reactant.

Paper 1

4.4 - Chemical changes

4.4.1.1,4.4.1.2,4.4.1.3 - Metal reactions, reactivity and extractionLearn how metal oxides form in oxidation reactions (4.4.1.1), how reactions with water, dilute acids and other metal compounds reveal a reactivity order (4.4.1.2), and how that order helps choose a method of extracting a metal (4.4.1.3). The connection is that a metal's readiness to react determi...
4.4.2.1,4.4.2.2,4.4.2.4 - Acids, neutralisation and pHLearn why acids form salts with metals (4.4.2.1), bases, alkalis and carbonates (4.4.2.2), then use ions and the pH scale to explain neutralisation (4.4.2.4). Product predictions and ion formulae let you choose reactants for a named salt, while electron-transfer equations explain the particle cha...
4.4.2.3 - Preparing soluble saltsLearn how to choose reactants and turn a salt solution into a pure, dry crystalline sample. The required practical uses an insoluble oxide or carbonate with dilute acid, followed by filtration, gentle evaporation and crystallisation. Understanding what each step removes helps you adapt the method...
4.4.2.5 - Acid–alkali titrationLearn how a pipette, burette and suitable indicator measure the reacting volumes of a strong acid and a strong alkali accurately. Required practical 2 includes repeat titrations, careful readings and a justified mean, allowing a salt to be prepared without excess acid or alkali.
4.4.2.6 - Strong and weak acidsLearn to separate how much acid is dissolved from how fully it ionises. Use that distinction to compare strong and weak acids, explain pH differences and calculate whole-number pH comparisons as powers of ten. A dilute strong acid and a concentrated weak acid describe different combinations of th...
4.4.3.1,4.4.3.2 - Electrolysis of molten compoundsLearn why an ionic compound conducts when its ions can move and how electric current drives electrolysis (4.4.3.1). Then predict the elements obtained from a molten binary ionic compound at each electrode (4.4.3.2). The key is to follow ion charge and distinguish movement through the liquid from...
4.4.3.3 - Extracting aluminium by electrolysisLearn why aluminium needs electrolysis, why its oxide is used with molten cryolite, and why the carbon anodes are continually consumed. The process links metal reactivity, ionic conduction, electron transfer and energy demand.
4.4.3.4 - Aqueous electrolysis and its investigationLearn how water changes the possible products of electrolysis for a solution containing a single ionic compound. Required practical 3 develops a hypothesis, controls an investigation using inert electrodes, and identifies products from observations and gas tests.
4.4.3.5 - Electrode half equationsLearn to represent cathode reductions and anode oxidations with balanced half equations. Work from the reacting ions to the element formed, then conserve atoms and charge using electrons. The method applies to molten compounds, aluminium extraction and aqueous electrolysis, including hydrogen and...

4.5 - Energy changes

4.5.1.1 - Exothermic and endothermic reactionsChemical reactions transfer energy between the reacting substances and their surroundings. Learn to identify the direction of this transfer, judge useful applications, and investigate the variables that affect temperature changes in reacting solutions.
4.5.1.2 - Reaction profiles and activation energyA reaction profile shows why a reaction can need an initial energy input even when it eventually warms its surroundings. Learn to read and draw the relative energy levels of reactants and products, the activation-energy barrier, and the overall energy change.
4.5.1.3 - Bond energies and reaction energy changesBond breaking and bond formation explain the overall energy transfer in a reaction. Learn to count bonds from balanced equations, use supplied bond energies, and calculate or interpret the balance between energy taken in and released.
4.5.2.1,4.5.2.2 - Cells, batteries and hydrogen fuel cellsChemical cells use reactions to provide electricity, while hydrogen fuel cells keep operating when fuel and oxygen are supplied. Learn how electrode and electrolyte choices affect cells, how batteries and recharging work, and how to evaluate energy devices.

Paper 2

4.6 - Rate and extent of chemical change

4.6.1.1 - Measuring rates and interpreting rate graphsReaction rate describes how quickly reactants are used or products are formed. Learn to calculate mean rates, draw and interpret quantity–time curves, recognise tangent slopes and connect a rate's unit to the quantity measured.
4.6.1.2,4.6.1.3,4.6.1.4 - Collision theory, rate factors and catalystsCollision theory explains why changing concentration, gas pressure, solid surface area, temperature or a catalyst changes reaction rate. Learn how these factors affect collision frequency or the activation-energy requirement, and use particle explanations to predict unfamiliar situations.
4.6.1.2 - Investigating concentration and rateRequired practical 5 investigates how concentration affects reaction rate using both gas-volume measurements and a colour or turbidity change. Learn to develop a testable hypothesis, control conditions, collect results by both methods, and judge what the measurements can establish.
4.6.2.1,4.6.2.2,4.6.2.3 - Reversible reactions and dynamic equilibriumSome products can react to remake the original reactants, and the two directions transfer energy in opposite ways. Learn how changing conditions can reverse a chemical change and why a closed system can reach dynamic equilibrium while both reactions continue.
4.6.2.4,4.6.2.5,4.6.2.6,4.6.2.7 - Changing equilibrium conditionsThe composition of a reversible mixture at equilibrium depends on its conditions. Learn to use Le Chatelier's principle to predict the effects of concentration, temperature and gas pressure, then separate equilibrium yield from the speed of reaching it.

4.7 - Organic chemistry

4.7.1.1,4.7.1.2 - Crude oil, alkanes and fractional distillationLearn how crude oil formed, recognise the alkane family and explain how a refinery separates hydrocarbons by fractional distillation. These ideas connect the molecules in an underground resource to the fuels and chemical feedstocks used in everyday life.
4.7.1.3,4.7.1.4 - Hydrocarbon properties, combustion and crackingLearn how hydrocarbon size affects fuel properties, balance complete-combustion equations and explain how cracking makes useful smaller molecules. The properties in 4.7.1.3 explain fuel choices, while the reactions in 4.7.1.4 help refineries meet demand for fuels and chemical feedstocks.
4.7.2.1,4.7.2.2 - Alkenes and addition reactionsLearn to recognise and draw the first four alkenes, then use their carbon–carbon double bond to predict addition products. The structures in 4.7.2.1 explain the common reactions in 4.7.2.2, including making alkanes, alcohols and halogen-containing compounds.
4.7.2.3 - Alcohols and fermentationLearn to recognise the alcohol family, explain its characteristic reactions and understand how yeast makes ethanol from sugar. You will connect the first four alcohol structures to their uses, combustion and practical observations.
4.7.2.4 - Carboxylic acids and estersLearn to recognise the first four carboxylic acids, describe their reactions with carbonates and alcohols, and identify ethyl ethanoate as an ester. Ionisation explains how acidic solutions form, while functional groups explain the different organic products.
4.7.3.1 - Addition polymers and monomersLearn how alkene molecules join to form addition polymers and how to move between a monomer structure and a polymer repeating unit. Bond and atom checks let you predict unfamiliar structures without memorising a separate polymer for every monomer.
4.7.3.2,4.7.3.3 - Condensation polymers and amino acidsLearn how monomers with two functional groups make condensation polymers. Alcohol and acid groups in 4.7.3.2 form polyesters, while the two different groups of an amino acid in 4.7.3.3 form polypeptides and proteins.
4.7.3.4 - DNA and naturally occurring polymersLearn how nucleotide chains make DNA and how other naturally occurring polymers are built from amino acids or glucose. Comparing their monomers and chain arrangements explains why “natural polymer” describes a broad group of substances with different roles in life.

4.8 - Chemical analysis

4.8.1.1,4.8.1.2 - Purity and formulationsThis lesson distinguishes chemical purity from the everyday meaning of “pure”, uses melting and boiling evidence to judge a sample, and explains why useful products are often carefully designed mixtures. You will learn to recognise a formulation from its composition and the purpose of its ingredi...
4.8.1.3 - Chromatography and retention factorsPaper chromatography separates coloured mixtures and provides evidence about their components. This lesson explains the two phases, teaches the method for Required Practical 6, and shows how to interpret spots and calculate retention factors without overstating what one chromatogram proves.
4.8.2.1,4.8.2.2,4.8.2.3,4.8.2.4 - Identifying hydrogen, oxygen, carbon dioxide and chlorineThis lesson teaches the characteristic tests for hydrogen, oxygen, carbon dioxide and chlorine. You will connect each method to its positive observation and use those observations to identify gases without relying on colour, smell or a predicted reaction alone.
4.8.3.1,4.8.3.2 - Flame tests and metal hydroxide testsThis lesson identifies metal ions using flame colours and precipitates formed with sodium hydroxide solution. It teaches the cation methods in Required Practical 7, explains how extra tests distinguish similar results, and builds balanced equations for insoluble metal hydroxides.
4.8.3.3,4.8.3.4,4.8.3.5 - Tests for carbonate, halide and sulfate ionsThis lesson identifies carbonate, chloride, bromide, iodide and sulfate ions through gas and precipitation tests. It teaches the anion methods in Required Practical 7, including why reagents are added in the right order and why separate fresh portions are needed to identify an unknown ionic compo...
4.8.3.6,4.8.3.7 - Instrumental analysis and flame emission spectroscopyInstrumental methods can detect small amounts of substances and turn observations into measurements. This lesson compares them with chemical tests, explains flame emission spectroscopy, and uses reference spectra and calibration data to identify metal ions and determine their concentrations.

4.9 - Chemistry of the atmosphere

4.9.1.1,4.9.1.2,4.9.1.3,4.9.1.4 - The atmosphere and its evolutionEarth's atmosphere has changed as gases were released, removed and produced by living organisms. This lesson compares today's main gases with a model of the early atmosphere, explains the increase in oxygen and decrease in carbon dioxide, and connects those changes to oceans, limestone and fossil...
4.9.2.1,4.9.2.2 - Greenhouse gases and human activitiesThe greenhouse effect helps keep Earth warm enough for life, but human activities can increase the gases responsible for it. This lesson explains radiation and warming, identifies carbon dioxide and methane sources, and teaches how to judge climate evidence, models and reports.
4.9.2.3,4.9.2.4 - Climate change and carbon footprintsClimate change can affect coastlines, rainfall, weather and ecosystems, with risks that vary between places. This lesson explains those consequences, accounts for greenhouse-gas emissions over a complete life cycle, and evaluates ways to reduce carbon footprints together with the barriers to acting.
4.9.3.1,4.9.3.2 - Air pollutants from fuelsBurning a fuel can produce more than carbon dioxide and water, depending on its composition, oxygen supply and temperature. This lesson explains the formation and effects of carbon monoxide, particulates, sulfur dioxide and nitrogen oxides, then uses that chemistry to predict emissions and evalua...

4.10 - Using resources

4.10.1.1,4.10.2.2 - Resources, sustainability, reuse and recyclingLearn how natural, agricultural and synthetic resources meet human needs, how chemistry supports sustainable development, and how reducing use, reusing products and recycling materials can conserve limited resources.
4.10.2.1 - Life cycle assessmentsLearn how to compare the environmental impacts of products throughout their lives, calculate meaningful comparisons from data, and explain why a life cycle assessment depends on boundaries and value judgements.
4.10.1.2 - Potable water and water analysisLearn what makes water safe to drink, how fresh and salty water are treated, and how to analyse and purify samples using pH measurements, dissolved-solid measurements and distillation in required practical 8.
4.10.1.3 - Waste water treatmentLearn why sewage, agricultural and industrial waste water need treatment, how physical and biological processes remove different contaminants, and how starting conditions affect the difficulty of obtaining potable water.
4.10.1.4 - Phytomining and bioleachingLearn how plants and bacteria help extract copper from low-grade resources, how copper is recovered from solutions, and how biological routes compare with conventional extraction using evidence.
4.10.3.1,4.10.3.2 - Corrosion protection and useful alloysLearn the conditions needed for rusting, how barrier and sacrificial protection prevent corrosion, and how the composition of copper, gold, steel and aluminium alloys makes them suitable for particular uses.
4.10.3.3 - Ceramics, polymers and compositesLearn how ceramics, polymers and composites are made, how polymer structure affects melting and density, and how to use quantitative property data to select a material for a stated purpose.
4.10.4.1 - The Haber processLearn how nitrogen and hydrogen are converted into ammonia and how the industrial process separates and recycles gases. Reacting gas ratios and the balance between equilibrium yield, production rate and cost explain the quantitative and commercial decisions.
4.10.4.2 - Producing NPK fertilisersLearn how nitrogen, phosphorus and potassium compounds are combined into fertiliser formulations, how ammonia and mined resources supply them, and how industrial manufacture differs from preparing an ammonium salt in the laboratory.

Papers 1 and 2 (skills)

Scientific and mathematical skills

3 - Scientific models, evidence and decisionsLearn how scientific explanations are developed and tested, how evidence supports decisions about chemical technologies, and how uncertainty changes the strength of a conclusion. These skills help you judge a claim using its methods and results, then communicate what the evidence actually supports.
3 - Experimental design and practical measurementsLearn how to turn a chemical question into a valid investigation, choose and use apparatus, record measurements and evaluate the evidence produced. These skills connect the reasoning behind a method with the practical decisions that make its results useful.
7 - Mathematics and graphs in chemistryLearn how units, proportions and algebra connect chemical measurements, and how tables and graphs reveal the relationships within results. Worked examples show how to select a method, preserve units and precision, and interpret what a numerical or graphical result means.