Chemistry

Scientific models: what they are and why we use them

Developing hypotheses from scientific ideas

Variables: independent, dependent and control

Writing a clear, testable prediction

Planning a method: accuracy, precision and range

Risk assessments: hazards, risks and control measures

Choosing apparatus for accuracy (pipettes, burettes, balances)

Recording results in tables with headings and units

Drawing graphs: choosing scales and plotting points

Using lines of best fit and interpreting trends

Reliability: repeats, means and anomalies

Uncertainty: resolution, range and systematic vs random error

Evaluating a method and suggesting improvements

Using SI units, prefixes and standard form

Significant figures in practical calculations

Required practical sign-off: what must be recorded and why (Pearson Qualifications)

Memorising common element symbols and simple formulae

Writing formulae for common ions

Turning word equations into symbol equations

Balancing symbol equations step-by-step

State symbols: solid, liquid, gas and aqueous

Writing ionic equations from full equations

Identifying common hazard symbols

Matching hazard symbols to lab precautions

Evaluating risk in a practical method and improving safety (Pearson Qualifications)

How the Dalton model changed with new discoveries

Inside the atom: protons, neutrons and electrons

Relative charge and relative mass of subatomic particles

Why atoms have equal numbers of protons and electrons

Atomic number and mass number

Isotopes and why they exist

Calculating protons, neutrons and electrons in atoms and ions

Relative atomic mass from isotope abundance data

Mendeleev’s periodic table: evidence and predictions

Periods and groups: what the table shows

Metals vs non-metals from position and structure

Electronic configuration for the first 20 elements (shell model)

Linking electron configuration to group and period

Forming ions by electron transfer (dot-and-cross)

Naming ionic compounds: -ide vs -ate

Writing ionic formulae from ion charges

Ionic lattices and why ionic compounds have high melting points

When ionic substances conduct electricity (solid vs molten vs aqueous)

Covalent bonds as shared pairs of electrons

Dot-and-cross for key molecules (H2, HCl, H2O, CH4, O2, CO2)

Intermolecular forces and why simple molecules have low boiling points

Diamond vs graphite: structure and properties

Graphene and fullerenes: structure and key properties

Metals: delocalised electrons and metallic bonding

Polymers as long carbon-chain molecules (intro)

Limits of models (dot-and-cross, ball-and-stick, 2D/3D)

Relative formula mass (Mr) calculations

Percentage by mass calculations

Empirical formula from reacting masses

Empirical formula from percentage composition

Conservation of mass in reactions

Reacting masses from balanced equations

Concentration calculations (g/dm³ and mol/dm³)

The mole as “amount of substance”

Limiting reactants and “excess” in calculations (Pearson Qualifications)

Particle model: solids, liquids and gases

Naming changes of state (melting, boiling, condensing, freezing, sublimation)

Explaining changes of state using energy and particle movement

Using data to predict state at given conditions

“Pure” in chemistry vs everyday “pure”

Pure substances vs mixtures: key differences

Melting point range vs sharp melting point (purity)

Simple distillation: when and why it works

Fractional distillation: separating liquids with different boiling points

Filtration: separating insoluble solids from liquids

Crystallisation: making a soluble salt from solution

Paper chromatography: stationary and mobile phase

Interpreting chromatograms for purity and identity

Calculating and using Rf values

Core practical: inks by chromatography and simple distillation (Pearson Qualifications)

Choosing the best separation method from substance properties

Making water potable: sedimentation, filtration and chlorination

Distillation to make seawater potable

Why water used in analysis must be salt-free (Pearson Qualifications)

Acids and alkalis as H+ and OH– sources

The pH scale and what pH 7 means

Indicators: litmus, methyl orange, phenolphthalein

pH and ion concentration (10× rule)

Core practical: tracking pH during neutralisation (Ca(OH)2/CaO) (Pearson Qualifications)

Concentrated vs dilute (amount of solute)

Strong vs weak acids (degree of dissociation)

Bases vs alkalis (soluble base)

Acids reacting with metals: products and observations

Acids reacting with metal oxides/hydroxides: neutralisation to salts

Acids reacting with carbonates: CO2 production

Gas tests: hydrogen (pop) and carbon dioxide (limewater)

Neutralisation as acid + base

Neutralisation at particle level: H+ + OH– → H2O

Making soluble salts using an insoluble reactant (excess, filter, crystallise)

Making soluble salts using a soluble reactant (titration needed)

Core practical: preparing hydrated copper sulfate crystals (water bath) (Pearson Qualifications)

Titration method to make a pure dry salt (overview)

Solubility rules for common salts

Predicting precipitates from solubility rules

Making an insoluble salt by precipitation (filter, wash, dry)

Electrolytes: ionic compounds molten or in solution

Electrolysis as decomposition using direct current

Ion movement to electrodes (anions → anode, cations → cathode)

Predicting products: aqueous electrolysis (competition rules)

Predicting products: molten ionic compounds

Half-equations at anode and cathode

Oxidation and reduction as electron loss/gain

Electrolysis: oxidation at anode, reduction at cathode

Copper purification using electrolysis (copper electrodes)

Core practical: electrolysis of CuSO4 with inert vs copper electrodes (Pearson Qualifications)

Reactivity of metals from reactions with water, acids and salt solutions

Displacement reactions as redox (electron transfer)

The reactivity series (including carbon and hydrogen reference points)

Metals in ores vs native metals (uncombined elements)

Oxidation and reduction in terms of oxygen gain/loss

Extraction as reduction of ores

Carbon reduction vs electrolysis: choosing a method (cost + reactivity)

Iron extraction idea (meaning of “reduction by carbon”)

Aluminium extraction by electrolysis (why it’s expensive)

Bioleaching and phytoextraction (why they’re alternatives)

Corrosion resistance and reactivity series links

Recycling metals: environmental and economic benefits

Life cycle assessment: raw materials → manufacture → use → disposal

Interpreting LCA data to make a judgement

Reversible reactions and the ⇌ symbol

Dynamic equilibrium: forward rate = reverse rate

Ammonia formation as a reversible reaction (Haber overview)

Haber process conditions: temperature, pressure, catalyst (Pearson Qualifications)

Predicting equilibrium shifts (temperature, pressure, concentration) (Pearson Qualifications)

Transition metals: typical properties (density, mp, coloured compounds, catalysis)

Corrosion as oxidation of metals

Preventing rust: exclude oxygen, exclude water, sacrificial protection

Electroplating: why and how it improves appearance/corrosion resistance

Alloys: why mixing metals changes properties

Why steel is an alloy (and why pure iron is limited)

Linking metal uses to properties (Al, Cu, Au; magnalium, brass)

Concentration in mol/dm³: calculating from moles and volume

Converting between g/dm³ and mol/dm³

Core practical: acid–alkali titration (apparatus, method, endpoint) (Pearson Qualifications)

Titration calculations: finding unknown concentration or volume

Percentage yield: actual vs theoretical

Why yield is usually <100% (incomplete, losses, side reactions)

Atom economy: what it means for sustainability

Calculating atom economy from equations

Choosing pathways using yield, atom economy, rate, equilibrium, by-products

Molar volume at r.t.p. (24 dm³ per mole) and what it means

Using molar volume in reacting-mass calculations

Avogadro’s law: using mole ratios to compare gas volumes

Haber process revisited: equilibrium as a dynamic process

Conditions affecting rate of reaching equilibrium (T, P, concentration, catalyst)

Industry trade-offs: acceptable yield in acceptable time

NPK fertilisers: what the letters mean and why plants need them

Ammonia + nitric acid → fertiliser salt (ammonium nitrate concept)

Making ammonium sulfate in the lab (small-scale method)

Comparing lab vs industrial-scale fertiliser manufacture

Chemical cells: voltage until a reactant is used up

Hydrogen–oxygen fuel cells: reactants and products

Evaluating fuel cells for specific uses (pros/cons) (Pearson Qualifications)

Locating group 1, group 7 and group 0 from periodic table position

Group 1 properties: soft and low melting points

Group 1 reactions with water (Li, Na, K): observations and products

Group 1 reactivity trend down the group

Explaining group 1 trend using electron configuration

Group 7 colours and states (Cl2, Br2, I2)

Group 7 physical trends down the group

Test for chlorine gas

Halogens reacting with metals to form metal halides

Hydrogen halides and acidic solutions (pattern down the group)

Halogen displacement reactions with halide ions

Using displacement to order halogen reactivity (including astatine)

Displacement as redox: identifying what’s oxidised and reduced

Explaining group 7 reactivity trend using electron configuration

Why noble gases are inert (full outer shell)

Uses of noble gases from inertness, low density and non-flammability

Trends in noble gas physical properties down the group (Pearson Qualifications)

What “rate of reaction” means in real experiments

Core practical: rate using gas volume (marble chips + acid) (Pearson Qualifications)

Core practical: rate using disappearing cross (thiosulfate + acid) (Pearson Qualifications)

Drawing and interpreting rate graphs (steeper = faster)

Calculating rate from gradients and time data

Collision theory: why reactions happen

Effect of concentration on rate (collision frequency)

Effect of temperature on rate (collision energy and activation energy)

Effect of surface area on rate (exposed particles)

Catalysts: lowering activation energy

Enzymes as biological catalysts (basic idea)

Exothermic vs endothermic reactions (energy out vs in)

Reaction profiles: reading energy diagrams

Activation energy on reaction profiles

Bond breaking vs bond making and energy changes

Calculating overall energy change using bond energies

Using profiles to compare catalysed vs uncatalysed reactions (Pearson Qualifications)

Hydrocarbons as compounds of only hydrogen and carbon

Crude oil as a complex mixture of hydrocarbons

Crude oil as a finite resource and why that matters

Fractional distillation of crude oil: how separation works

Fractions and their uses (gases, petrol, kerosene, diesel, fuel oil, bitumen)

Why fraction properties change with chain length (bp, viscosity, ignition)

Homologous series: definition and CH2 pattern

Complete combustion of hydrocarbons (products + energy)

Incomplete combustion: carbon monoxide and soot

Why carbon monoxide is toxic

Problems from incomplete combustion in appliances

Sulfur impurities and sulfur dioxide formation

Acid rain from sulfur dioxide: impacts

Nitrogen oxides from high-temperature engines

Hydrogen vs petrol as a car fuel (advantages and disadvantages)

Fossil fuels: petrol/kerosene/diesel from crude oil; methane from natural gas

Cracking: turning long alkanes into shorter alkanes and alkenes

Why cracking is needed (demand for fuels and feedstock)

Earth’s early atmosphere from volcanic gases

Early atmosphere evidence (little O2, lots CO2, water vapour)

Ocean formation by condensation of water vapour

CO2 decrease by dissolving in oceans

Oxygen increase from photosynthesis (primitive plants)

Test for oxygen (relights glowing splint)

Greenhouse effect: how gases absorb and re-radiate heat

Evaluating evidence for human-caused climate change (correlation + uncertainty)

Today’s atmosphere composition

Impacts of increased CO2 and methane and possible mitigation (Pearson Qualifications)

Why each ion test must be unique

Flame tests: identifying Li+, Na+, K+, Ca2+, Cu2+

Cation tests with sodium hydroxide: Al3+, Ca2+, Cu2+, Fe2+, Fe3+, NH4+

Test for ammonia gas

Carbonate test: acid then CO2 confirmation

Sulfate test: acid then barium chloride

Halide tests: nitric acid then silver nitrate (Cl–, Br–, I–)

Core practical: identifying ions in unknown salts (Pearson Qualifications)

Using test results to deduce the ions present

Instrumental methods: why they can be faster/more accurate

Flame photometry: calibration curve to find concentration

Flame photometry: identifying ions from reference results

Drawing and naming alkanes (methane, ethane, propane, butane)

Why alkanes are saturated

Drawing and naming alkenes (ethene, propene, butenes)

Why alkenes are unsaturated and the C=C functional group

Addition reaction: alkene + bromine (structures of reactants/products)

Bromine water test for unsaturation (alkenes vs alkanes)

Combustion of alkanes and alkenes as oxidation

What polymers are (repeating units, high Mr)

Making poly(ethene) from ethene (addition polymerisation)

Other addition polymers: poly(propene), PVC, PTFE

Linking monomers and polymers (deducing one from the other)

Polymer uses linked to properties (PE, PP, PVC, PTFE)

Polyesters as condensation polymers (water formed each link)

Problems with polymers (landfill persistence, combustion gases, sorting)

Evaluating polymer recycling (economic and environmental trade-offs)

Natural polymers: DNA, starch and proteins (what they’re made from)

Drawing alcohols (methanol, ethanol, propan-1-ol, butan-1-ol)

Alcohol functional group and dehydration to alkenes

Core practical: comparing heats of combustion of alcohols (Pearson Qualifications)

Drawing carboxylic acids (methanoic to butanoic)

Carboxylic acid functional group and acidic properties

Oxidising ethanol to ethanoic acid (and extension idea)

Using functional groups to predict reactions in a homologous series

Ethanol by fermentation (yeast enzymes)

Concentrating ethanol by fractional distillation after fermentation

Nanoparticles: size compared to atoms and molecules

Nanoparticles: surface area to volume ratio and uses (e.g. sunscreens)

Nanoparticles: possible risks

Comparing materials using data (glass/clay ceramics, polymers, composites, metals)

Selecting materials for uses based on properties and data (Pearson Qualifications)