Cambridge International · International A Level · 9701
Chemistry — Keywords & Key Terms — Definitions Glossary (2026)
Cambridge International A Level Chemistry (9701)
Topic-by-topic keywords, key terms and definitions for precise exam language—separate from our revision checklists (topic coverage) and formula sheets (equations).
Keywords & Key Terms — definitions
Examiner-style keywords and definitions organised by syllabus topic. Terms are tagged Essential (start here), Core (typical exam standard), and Advanced for harder distinctions — tick each row when you can recall it. Your progress is saved in this browser for this list.
Cambridge International International A Level Chemistry (9701)
Cambridge International International A Level Chemistry (9701)
Cambridge International A Level Chemistry (9701)
Cambridge 9701 is organised into physical chemistry, inorganic chemistry and organic chemistry with practical skills (Paper 3 / Paper 5). Topics include atomic structure, bonding, energetics, kinetics, equilibria, electrochemistry, Group chemistry, transition metals, and organic mechanisms through to polymers and biochemistry context as specified.
Mark schemes: Organic responses: curly arrows from bond or lone pair to electrophilic centre; show dipoles δ+/δ− where relevant. Physical chemistry: state symbols in equations; correct signs for ΔH; K expressions use equilibrium concentrations/partial pressures with stoichiometric powers. ‘Explain’ in kinetics/equilibria should reference collision theory or Le Chatelier with correct conditions.
Active recall: 0 / 50 terms ticked
| Recalled | Topic | Level | Keyword | Definition |
|---|---|---|---|---|
| Atomic structure & bonding | Core | First ionisation energy | Energy to remove one mole of electrons from one mole of gaseous atoms. | |
| Atomic structure & bonding | Core | Successive ionisation energies | Evidence for shells and group number. | |
| Atomic structure & bonding | Core | Electronegativity | Relative attraction for bonding electrons — Pauling scale. | |
| Atomic structure & bonding | Core | Bond energy | Enthalpy to break 1 mole of a specific bond in gas phase. | |
| Atomic structure & bonding | Core | Lattice energy | Enthalpy change forming one mole of ionic lattice from gaseous ions. | |
| Atomic structure & bonding | Core | Born–Haber cycle | Thermochemical cycle for lattice energy and related enthalpies. | |
| Atomic structure & bonding | Advanced | Polarisation of anion | Large anion + small highly charged cation — covalent character (Fajans). | |
| Atomic structure & bonding | Core | Hybridisation | sp, sp², sp³ — explains bond angles in organic and molecular structures. | |
| Energetics & thermodynamics | Core | Enthalpy change ΔH | Heat energy change at constant pressure. | |
| Energetics & thermodynamics | Core | Standard conditions | 298 K, 100 kPa, stated states. | |
| Energetics & thermodynamics | Core | Hess’s law | ΔH route-independent — construct cycles. | |
| Energetics & thermodynamics | Core | Bond enthalpy | Average across molecules — use with care in calculations. | |
| Energetics & thermodynamics | Core | Entropy S | Measure of disorder; units J mol⁻¹ K⁻¹. | |
| Energetics & thermodynamics | Advanced | Gibbs free energy | ΔG = ΔH − TΔS; ΔG < 0 feasible under constant p and T. | |
| Kinetics | Core | Rate of reaction | Change in concentration per unit time. | |
| Kinetics | Core | Order with respect to A | Exponent of [A] in experimentally determined rate equation. | |
| Kinetics | Core | Overall order | Sum of individual orders. | |
| Kinetics | Core | Rate constant k | Depends on temperature via Arrhenius: k = Ae^(−Ea/RT). | |
| Kinetics | Core | Half-life | For first order: t½ independent of [A]; for zero order: t½ ∝ [A]₀. | |
| Kinetics | Advanced | Boltzmann distribution | Fraction of molecules with E ≥ Ea increases with T — explains rate. | |
| Chemical equilibria | Core | Dynamic equilibrium | Forward and reverse rates equal; concentrations constant in closed system. | |
| Chemical equilibria | Core | Kc | Equilibrium constant from equilibrium concentrations — powers = stoichiometry. | |
| Chemical equilibria | Core | Kp | Partial pressures for gas equilibria. | |
| Chemical equilibria | Core | Kp and Kc | Kp = Kc(RT)^Δn when applicable. | |
| Chemical equilibria | Advanced | Le Chatelier’s principle | System at equilibrium partially counteracts imposed change — qualitative predictions. | |
| Chemical equilibria | Core | Partition coefficient | Ratio of solute concentrations in two immiscible solvents at equilibrium. | |
| Acids, bases & buffers | Core | Brønsted–Lowry acid | Proton donor. | |
| Acids, bases & buffers | Core | Brønsted–Lowry base | Proton acceptor. | |
| Acids, bases & buffers | Core | pKa | −log10 Ka — smaller pKa means stronger acid. | |
| Acids, bases & buffers | Core | Buffer solution | Resists pH change — weak acid + conjugate base salt (or weak base + salt). | |
| Acids, bases & buffers | Advanced | Henderson–Hasselbalch | pH = pKa + log([A⁻]/[HA]) for acid buffer. | |
| Acids, bases & buffers | Core | Indicator | Weak acid with different colours for HIn and In⁻ — pKin ≈ pH at endpoint. | |
| Electrochemistry | Core | Standard electrode potential E° | Potential of half-cell vs standard hydrogen electrode. | |
| Electrochemistry | Core | Cell e.m.f. | E°cell = E°red − E°oxid or right − left in cell diagram context. | |
| Electrochemistry | Core | Electrolysis | External supply drives non-spontaneous reaction. | |
| Electrochemistry | Core | Faraday constant | Charge per mole of electrons — mass deposited m = QMr/nF. | |
| Electrochemistry | Advanced | Nernst equation | Concentration dependence of electrode potential — qualitative at A Level. | |
| Inorganic trends | Core | Periodicity | Repeating trends across a period. | |
| Inorganic trends | Core | Group 2 trends | Atomic radius, reactivity with water/oxygen, thermal stability of nitrates/carbonates. | |
| Inorganic trends | Core | Group 17 trends | Boiling points, reactivity as oxidising agents, displacement. | |
| Inorganic trends | Core | Transition metals | Variable oxidation states, coloured complexes, catalytic behaviour. | |
| Inorganic trends | Advanced | Ligand exchange | Substitution in complex ions — colour changes. | |
| Organic mechanisms & functional groups | Core | Electrophile | Electron-pair acceptor (e.g. NO₂⁺, δ+ on carbonyl C). | |
| Organic mechanisms & functional groups | Core | Nucleophile | Electron-pair donor (e.g. OH⁻, NH₃, CN⁻). | |
| Organic mechanisms & functional groups | Core | SN1 / SN2 | Unimolecular vs bimolecular nucleophilic substitution — carbocation stability vs sterics. | |
| Organic mechanisms & functional groups | Core | Elimination | E1/E2 — competition with substitution; base strength and temperature. | |
| Organic mechanisms & functional groups | Core | Electrophilic addition | Alkenes + H⁺ then nucleophile; bromine via polarised Br₂. | |
| Organic mechanisms & functional groups | Advanced | Electrophilic aromatic substitution | Nitration, halogenation — mechanism with NO₂⁺, X⁺. | |
| Organic mechanisms & functional groups | Core | Nucleophilic addition–elimination | Acyl chlorides / anhydrides with nucleophiles. | |
| Organic mechanisms & functional groups | Core | Carbonyl chemistry | Aldehyde vs ketone reactivity — Tollens, Fehling’s. |
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Chemistry (9701) — Keywords & Key Terms FAQ
- What is on this Cambridge International International A Level Chemistry keywords and key terms list?
- It is a topic-organised glossary of important chemistry terms with short, exam-style definitions aligned to Cambridge International A Level Chemistry (9701) (9701). It is designed for “define”, “state”, “outline” and “explain” questions where precise vocabulary earns marks.
- How should I use this Chemistry glossary alongside past papers?
- Tick terms when you can recall them without reading the answer, then check your wording against mark schemes. Pair vocabulary practice with past papers for International A Level Chemistry (9701) so you apply terms in context.
- Is this the same as a revision checklist or a formula sheet?
- No. Revision checklists help you track which syllabus topics you have covered and your confidence—separate pages on Tutopiya. Formula sheets summarise equations and quantitative relationships. This page is only a definitions and key-terms glossary for Chemistry. Quantitative relationships belong on formula sheets; this list emphasises language and concepts.
- Can I download this Chemistry keywords and key terms list for free?
- Yes. After a quick free sign-up you can download a UTF-8 CSV (opens in Excel or Google Sheets) or open a print-friendly page and save as PDF. Browsing the list on the page is free.
- Is this Chemistry list aligned to the 9701 specification?
- Topic groupings and wording follow Cambridge International A Level Chemistry (9701) for Cambridge International International A Level. Always confirm final learning objectives and any regional options in your official specification and recent examiner reports for your exam session.
- Why focus on definitions instead of full notes?
- Mark schemes reward correct technical terms and clear links between ideas. A compact glossary lets you drill the exact language examiners expect for Chemistry at International A Level, separate from longer notes or topic trackers.