G3 Science (Chemistry)
Study the G3 Combined Chemistry component in syllabus order with canonical lessons, practice and assessment.
Learning goals
- name appropriate apparatus for the measurement of time, temperature, mass and volume; including burettes, pipettes, measuring cylinders and gas syringes
- suggest suitable apparatus, given relevant information, for a variety of simple experiments, including collection of gases and measurement of rates of reaction.
- describe methods of separation and purification for the components of mixtures, to include: — use of a suitable solvent, filtration and crystallisation or evaporation
- describe methods of separation and purification for the components of mixtures, to include: — distillation and fractional distillation (see also 11.1(b))
- describe methods of separation and purification for the components of mixtures, to include: — paper chromatography
- suggest suitable separation and purification methods, given information about the substances involved in the following types of mixtures: — solid-solid
- suggest suitable separation and purification methods, given information about the substances involved in the following types of mixtures: — solid-liquid
- suggest suitable separation and purification methods, given information about the substances involved in the following types of mixtures: — liquid-liquid (miscible)
- interpret paper chromatograms including comparison with ‘known’ samples (the use of Rf values is not required)
- deduce from given melting point and boiling point data the identities of substances and their purity.
- follow a sequence of instructions;
- use techniques, apparatus and materials;
- make and record observations, measurements and estimates;
- interpret and evaluate observations and experimental results;
- plan investigations, select techniques, apparatus and materials;
- evaluate methods and suggest possible improvements.
- describe the solid, liquid and gaseous states of matter and explain their interconversion in terms of the kinetic particle theory and of the energy changes involved.
- state the relative charges and approximate relative masses of a proton, a neutron and an electron
- describe, with the aid of diagrams, the structure of an atom as consisting of protons and neutrons (nucleons) in the nucleus and electrons arranged in shells (energy levels) (knowledge of s, p, d and f classification is not required; a copy of the Periodic Table will be available in the examination)
- define proton (atomic) number and nucleon (mass) number
- interpret and use nuclide notations such as ¹²₆C
- define the term isotopes
- deduce the numbers of protons, neutrons and electrons in atoms and ions given proton and nucleon numbers.
- describe the formation of ions by electron loss/gain and that these ions usually have the electronic configuration of a noble gas
- describe, including the use of ‘dot-and-cross’ diagrams, the formation of ionic bonds between metals and non-metals, e.g. NaCl; MgCl2
- relate the physical properties (including electrical property) of ionic compounds to their lattice structure.
- describe the formation of a covalent bond by the sharing of a pair of electrons and that the atoms in the molecules usually have the electronic configuration of a noble gas
- describe, using ‘dot-and-cross’ diagrams, the formation of covalent bonds between non-metallic elements, e.g. H2; O2; H2O; CH4; CO2
- deduce the arrangement of electrons in other covalent molecules
- relate the physical properties (including electrical property) of covalent substances to their structure and bonding.
- describe the differences between elements, compounds and mixtures
- describe the general physical properties of metals as solids having high melting and boiling points, malleable and good conductors of heat and electricity
- describe an alloy as a mixture of a metal with another element, e.g. brass; stainless steel
- identify representations of metals and alloys from diagrams of structures.
- state the symbols of the elements and formulae of the compounds mentioned in the syllabus
- deduce the formulae of simple compounds from the relative numbers of atoms present and vice versa
- deduce the formulae of ionic compounds from the charges on the ions present and vice versa
- interpret chemical equations with state symbols
- construct chemical equations, with state symbols, including ionic equations.
- define relative atomic mass, Ar
- define relative molecular mass, Mr, and calculate relative molecular mass (and relative formula mass) as the sum of relative atomic masses
- define the term mole in terms of the Avogadro constant
- calculate stoichiometric reacting masses and volumes of gases (one mole of gas occupies 24 dm3 at room temperature and pressure); calculations involving the idea of limiting reactants may be set (knowledge of the gas laws and the calculations of gaseous volumes at different temperatures and pressures are not required)
- apply the concept of solution concentration (in mol/dm3 or g/dm3) to process the results of volumetric experiments (e.g. titration) and to solve simple problems. (appropriate guidance will be provided where unfamiliar reactions such as redox are involved. Calculations on % yield and % purity are not required.)
- describe the meanings of the terms acid and alkali in terms of the ions they produce in aqueous solution and their effects on Universal Indicator
- describe neutrality and relative acidity and alkalinity, in terms of — relative H+ and OH– ion concentrations,
- describe neutrality and relative acidity and alkalinity, in terms of — colour in Universal Indicator, and
- describe neutrality and relative acidity and alkalinity, in terms of — the pH scale (calculation of pH from hydrogen ion concentration is not required)
- describe the characteristic properties of acids as in reactions with metals, bases and carbonates to form salts (description of the preparation of pure salts is not required)
- describe the reaction between hydrogen ions and hydroxide ions to produce water, H+ + OH– → H2O, as neutralisation
- describe the importance of controlling the pH in soils and how excess acidity can be treated using calcium hydroxide
- describe the characteristic properties of bases in reactions with acids and with ammonium salts
- classify oxides as acidic, basic, amphoteric or neutral based on metallic/non-metallic character.
- describe the use of aqueous sodium hydroxide and/or aqueous ammonia to identify the following aqueous cations through the formation of precipitates (if any) and their subsequent solubility: aluminium, ammonium (together with evolution of ammonia gas upon warming), calcium, copper(II), iron(II), iron(III) and zinc (formulae of complex ions are not required)
- describe tests to identify the following anions: carbonate (by the addition of dilute acid and subsequent use of limewater); chloride (by reaction of an aqueous solution with nitric acid and aqueous silver nitrate); nitrate (by reduction with aluminium in aqueous sodium hydroxide to ammonia and subsequent use of damp red litmus paper) and sulfate (by reaction of an aqueous solution with nitric acid and aqueous barium nitrate)
- describe tests to identify the following gases: ammonia (using damp red litmus paper); carbon dioxide (using limewater); chlorine (using damp litmus paper); hydrogen (using a burning splint); oxygen (using a glowing splint) and sulfur dioxide (using acidified potassium manganate(VII)).
- define oxidation and reduction (redox) in terms of oxygen/hydrogen gain/loss
- define redox in terms of electron transfer and changes in oxidation state
- describe the use of aqueous potassium iodide and acidified potassium manganate(VII) in testing for oxidising and reducing agents from the resulting colour changes.
- describe the Periodic Table as an arrangement of the elements in the order of increasing proton (atomic) number
- describe how the position of an element in the Periodic Table is related to proton number and electronic configuration
- explain the similarities between the elements in the same group of the Periodic Table in terms of their electronic configuration
- describe the change from metallic to non-metallic character from left to right across a period of the Periodic Table
- describe the relationship between number of outer (valence) electrons and metallic/non-metallic character
- predict the properties of elements in Group 1 and Group 17 using the Periodic Table.
- describe lithium, sodium and potassium in Group 1 (the alkali metals) as a collection of relatively soft, low density metals showing a trend in melting point and in their reaction with water
- describe chlorine, bromine and iodine in Group 17 (the halogens) as a collection of diatomic non- metals showing a trend in colour, state and their displacement reactions with solutions of other halide ions
- describe the lack of reactivity of the elements in Group 18 (the noble gases) in terms of their electronic configurations.
- place in order of reactivity calcium, copper, (hydrogen), iron, lead, magnesium, potassium, silver, sodium and zinc by reference to the reactions, if any, of the metals with water, steam and dilute hydrochloric acid
- deduce the order of reactivity from a given set of experimental results
- describe the ease of obtaining metals from their ores by relating the elements to their positions in the reactivity series
- describe the essential conditions for the corrosion (rusting) of iron as the presence of oxygen and water; prevention of rusting can be achieved by placing a barrier around the metal, e.g. painting; greasing; plastic coating.
- describe the term exothermic as a process or chemical reaction which transfers energy, often in the form of heat, to the surroundings and may be detected by an increase in temperature, e.g. the reaction between sodium hydroxide and hydrochloric acid
- describe the term endothermic as a process or chemical reaction which takes in energy, often in the form of heat, from the surroundings and may be detected by a decrease in temperature, e.g. the dissolving of ammonium nitrate in water.
- describe the effect of concentration, pressure, particle size and temperature on the rates of reactions and explain these effects in terms of collisions between reacting particles
- interpret data obtained from experiments concerned with rate of reaction.
- name natural gas, mainly methane, and crude oil as non-renewable sources of energy
- describe crude oil as a mixture of hydrocarbons and its separation by fractional distillation to yield fractions which have competing uses as fuels and as a source of chemicals (see also 1.2(a))
- describe biofuel (exemplified by bioethanol from sugarcane) as a renewable alternative to natural gas and crude oil
- describe how biofuel, when compared to fossil fuels, is more environmentally sustainable in terms of the offset in carbon dioxide emission during burning by that taken in during plant growth (see also 12(e)).
- describe a homologous series as a group of compounds with a general formula, similar chemical properties and showing a gradation in physical properties as a result of increase in the size and mass of the molecules, e.g. melting and boiling points; viscosity
- describe the alkanes as a homologous series of saturated hydrocarbons with the general formula CnH2n+2
- draw the structures of unbranched alkanes, C1 to C3, and name the unbranched alkanes methane to propane
- describe alkanes (exemplified by methane) as being generally unreactive except in terms of combustion and substitution by chlorine
- describe the alkenes as a homologous series of unsaturated hydrocarbons with the general formula CnH2n
- draw the structures of unbranched alkenes, C2 and C3, and name the unbranched alkenes ethene and propene
- describe the manufacture of alkenes and hydrogen by cracking hydrocarbons and recognise that cracking is essential to match the demand for fractions containing smaller molecules from the refinery process
- describe the difference between saturated and unsaturated hydrocarbons from their molecular structures and by using aqueous bromine
- describe the reactions of alkenes (exemplified by ethene) in terms of combustion, polymerisation (see also 11.4(b)) and the addition with bromine and hydrogen
- state the meaning of polyunsaturated when applied to food products
- describe the manufacture of margarine by the addition of hydrogen to unsaturated vegetable oils to form a solid product.
- describe the alcohols as a homologous series containing the –OH group
- draw the structures of unbranched alcohols, C1 to C3, and name the unbranched alcohols methanol to propanol
- describe the reactions of alcohols in terms of combustion and oxidation to carboxylic acids
- describe the formation of ethanol by fermentation of glucose
- describe the carboxylic acids as a homologous series containing the –CO2H group
- describe the formation of ethanoic acid by the oxidation of ethanol by atmospheric oxygen or acidified potassium manganate(VII).
- describe polymers as large molecules built up from small units (monomers), different polymers having different units
- describe the formation of poly(ethene) as an example of addition polymerisation of ethene as the monomer (see also 11.2(i))
- state some uses of poly(ethene) as a typical plastic, e.g. plastic bags; clingfilm
- deduce the structure of the addition polymer product from a given monomer and vice versa
- describe the pollution problems caused by the disposal of non-biodegradable plastics
- describe two methods of recycling plastics as — physical method (exemplified by melting small pieces of poly(ethene) waste into pellets)
- describe two methods of recycling plastics as — chemical method (exemplified by cracking of plastic waste into fuel)
- discuss the social, economic and environmental issues of recycling plastics.
- describe the volume composition of gases present in dry air as being approximately 78% nitrogen, 21% oxygen and the remainder being noble gases (with argon as the main constituent) and carbon dioxide
- name some common atmospheric pollutants, e.g. carbon monoxide; methane; nitrogen oxides (NO and NO2); ozone; sulfur dioxide; unburned hydrocarbons
- state the sources of these pollutants as — carbon monoxide from incomplete combustion of carbon-containing substances
- state the sources of these pollutants as — nitrogen oxides from lightning activity and internal combustion engines
- state the sources of these pollutants as — sulfur dioxide from volcanoes and combustion of fossil fuels
- discuss some of the effects of these pollutants on health and on the environment — the toxic nature of carbon monoxide
- discuss some of the effects of these pollutants on health and on the environment — the role of nitrogen dioxide and sulfur dioxide in the formation of ‘acid rain’ and its effects on respiration and buildings
- describe the carbon cycle in simple terms, to include — the processes of combustion, respiration and photosynthesis
- describe the carbon cycle in simple terms, to include — how the carbon cycle regulates the amount of carbon dioxide in the atmosphere (see also 11.1(d))
- state that carbon dioxide and methane are greenhouse gases and may contribute to global warming; give the sources of these gases and describe the potential effects of increased levels of these greenhouse gases, including more extreme weather events and melting of polar ice.
Start learning
Learn in order
Begin with Experimental Chemistry and follow the numbered roadmap.
Other ways to start
Find my starting point
Check eight ideas across the course and get a focused place to begin.
Prepare for an exam
Use mixed retrieval to choose what to review next.
Foundations and evidence
Experimental Chemistry
Study the complete G3 Science composition for measurement, gas collection, separation and purity.
The Particulate Nature of Matter
Build particle-state reasoning, then atomic and isotope structure, then ion and electron counting.
Chemical Bonding and Structure
Ionic and covalent bonding, structure–property links, metals and alloys.
Calculations and reactions
Chemical Calculations
Formulae, ionic equations, relative masses, moles, limiting reactants, gas volumes and solution concentration.
Acid-Base Chemistry
Ions, pH, reactions, neutralisation, soil treatment, bases and oxide classification.
Qualitative Analysis
Prescribed cation, anion and gas tests with observation-to-inference reasoning.
Redox Chemistry
Oxygen/hydrogen, electron-transfer and oxidation-state definitions plus prescribed reagent tests.
Patterns, energy and rate
Patterns in the Periodic Table
Periodic trends, Groups 1, 17 and 18, the reactivity series, extraction and rust prevention.
Chemical Energetics
Exothermic and endothermic changes interpreted through energy transfer and temperature evidence.
Rate of Reactions
Concentration, pressure, particle size and temperature explained using collisions, plus data interpretation.
Chemistry in society
Organic Chemistry
Fuels, C1–C3 hydrocarbons and alcohols, ethanoic acid, addition polymers and plastics recycling.
Maintaining Air Quality
Air composition, pollutant sources and effects, the carbon cycle and greenhouse gases.
Practice and continue learning
- Quiz practice — Choose course-specific topic practice or a mixed course check.
- Practical readiness — Check experimental design, then review the connected topic.
- Revision guide — See the whole G3 Science course and choose what to do next.
About this course
K326 / K328 Chemistry component · 2027
Study the SEC G3 Science Chemistry component shared by K326 and K328 through a clear syllabus roadmap and targeted practice.
This Chemistry component is shared by K326 Science (Physics, Chemistry) and K328 Science (Chemistry, Biology).
G3 Pure Chemistry (K324) is a separate, deeper syllabus. Some topics share lessons, but this course covers only what G3 Science needs.
Reviewed Aug 9, 2026
Questions about this course
Where should I start G3 Science Chemistry?
Start with the first roadmap topic on a first pass. During revision, return to the earliest topic you cannot complete independently.
What should I do when a topic is weak?
Use the topic guide to strengthen the explanation or calculation, then attempt a fresh question without notes before continuing.
When should I use mixed practice?
Use mixed practice to find weak areas. Then use topic practice and written responses to improve the exact reasoning that caused difficulty.
Review
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