IB Diploma Programme Chemistry Higher Level
IB Diploma Programme Chemistry Higher Level (first assessment 2025) is a rigorous two-year pre-university science course organized around two unifying concepts — Structure and Reactivity — that interweave quantitative calculation, mechanistic reasoning, and experimental inquiry across 240 teaching hours. The course spans six thematic strands (Structure 1–3, Reactivity 1–3), with Higher Level students additionally mastering Advanced Higher Level (AHL) extensions including Born-Haber energy cycles, Gibbs-energy spontaneity calculations, advanced acid-base and buffer equilibria, electrochemical cell thermodynamics, and multi-step organic reaction mechanisms. Assessment combines two written papers (Paper 1A MCQ + Paper 1B data-based, Paper 2 extended response) with an independent internal investigation worth 20% of the final grade.
270
Minutes
$123
Exam Cost
Who Should Take This
Pre-university students pursuing the IB Diploma who intend to study chemistry, biochemistry, medicine, pharmacy, chemical engineering, or any natural-science discipline at university, and who require the quantitative and mechanistic depth that selective universities expect at matriculation.
What's Covered
1Structure 1 — Models of the Particulate Nature of Matter
2Structure 2 — Models of Bonding and Structure
3Structure 3 — Classification of Matter
4Reactivity 1 — What Drives Chemical Reactions?
5Reactivity 2 — How Much, How Fast, and How Far?
6Reactivity 3 — What Are the Mechanisms of Chemical Change?
7Tools for Chemistry — Practical and Analytical Skills
What's Included in AccelaStudy® AI
Adaptive Knowledge Graph
Practice Questions
Lesson Modules
Console Simulator Labs
Exam Tips & Strategy
13 Activity Formats
Course Outline
1Structure 1 — Models of the Particulate Nature of Matter 3 topics
S1.1 Introduction to the Particulate Nature of Matter
- Recall the three states of matter and apply kinetic molecular theory to explain the macroscopic properties of solids, liquids, and gases in terms of particle arrangement, motion, and energy.
- Recall the definitions of element, compound, and mixture, and classify samples of matter using physical and chemical evidence.
S1.2 The Nuclear Atom
- Comprehend how isotopes differ in neutron count yet share chemical behavior, and calculate relative atomic mass from isotopic masses and natural abundances using mass-spectrometry data.
- Recall the nature of alpha, beta, and gamma radiation and write balanced nuclear equations for radioactive decay, identifying changes in atomic number and mass number.
S1.3 Electron Configuration
- Apply the Aufbau principle, Hund's rule, and the Pauli exclusion principle to write ground-state electron configurations in spdf notation for elements Z = 1–36, including exceptions at Cr and Cu.
- Analyze the shapes and spatial orientations of s, p, and d atomic orbitals, and explain how the four quantum numbers (n, l, ml, ms) uniquely define each electron's state within an atom (AHL).
- Analyze atomic emission spectra of hydrogen to calculate the energy and frequency of photon emission using E = hv and the Rydberg relationship, connecting spectral series to electron transitions between quantized energy levels.
2Structure 2 — Models of Bonding and Structure 4 topics
S2.1 Ionic Bonding and Structures
- Comprehend the electrostatic forces in ionic lattices and explain how charge density of ions determines lattice enthalpy magnitude, melting point, and solubility trends across a series of ionic compounds.
S2.2 Covalent Bonding
- Apply Lewis structure rules — including formal charge minimization and expanded octets for period 3 elements — to draw correct structures for molecules and polyatomic ions with up to five non-hydrogen atoms.
- Apply VSEPR theory to predict molecular geometry and bond angles for molecules with two to six electron domains including lone pairs, explaining how lone-pair repulsion deforms ideal geometries.
- Analyze molecular polarity by combining electronegativity differences with three-dimensional geometry to determine whether net dipole moments cancel or reinforce, predicting physical property differences between isomers.
- Apply sp, sp2, and sp3 hybridization models to explain the geometry and bond angles of organic and inorganic molecules, distinguishing sigma bonds formed by head-on orbital overlap from pi bonds formed by lateral p-orbital overlap (AHL).
S2.3 Metallic Bonding
- Comprehend the sea-of-electrons model of metallic bonding and use it to explain electrical and thermal conductivity, malleability, and variation in melting point across a period and down a group.
S2.4 Intermolecular Forces and Physical Properties
- Analyze the relative strength of London dispersion forces, dipole-dipole interactions, and hydrogen bonding, using them to explain and predict boiling point, viscosity, and surface tension trends for structurally related compounds.
- Comprehend the structure and properties of network covalent solids (diamond, graphite, silicon dioxide) and explain why each exhibits exceptional hardness or conductivity from the nature of its extended covalent bonding network.
3Structure 3 — Classification of Matter 3 topics
S3.1 The Periodic Table — Classification and Periodic Trends
- Analyze periodic trends in atomic radius, ionic radius, first ionization energy, electron affinity, and electronegativity across periods and down groups, explaining anomalies using effective nuclear charge and electron-shielding arguments.
- Apply knowledge of periodic trends to predict the acid-base character of Period 3 oxides and explain the physical and chemical properties of their halides from structure and bonding principles.
S3.2 Functional Groups — Organic Classification and Stereochemistry
- Recall and apply IUPAC nomenclature rules to name and draw structural formulas for alkanes, alkenes, alkynes, arenes, halogenoalkanes, alcohols, aldehydes, ketones, carboxylic acids, esters, amines, and amides up to six carbons.
- Analyze structural isomerism (chain, positional, functional group) and stereoisomerism (cis/trans geometric and optical enantiomeric) in organic compounds, identifying chiral centers and predicting optical activity from molecular symmetry (AHL).
S3.3 Transition Metals and Complex Ions
- Apply 3d/4s electron configuration rules to assign oxidation states of transition metals in ions and coordination compounds, explaining why multiple oxidation states arise from similar successive ionization energies of 3d electrons (AHL).
- Analyze the formation, geometry, and naming of transition-metal complex ions, applying the spectrochemical series to predict whether a given ligand produces high-spin or low-spin d-orbital splitting and its consequence for magnetic properties (AHL).
- Comprehend why transition-metal compounds are colored by linking the energy of absorbed visible photons to d-d electronic transitions induced by crystal-field splitting, and correlate predicted colors with colorimetric or UV-visible spectral data (AHL).
4Reactivity 1 — What Drives Chemical Reactions? 3 topics
R1.1 Measuring Enthalpy Changes
- Apply calorimetry data and q = mcDeltaT to calculate experimental enthalpy changes of combustion, neutralization, and dissolution reactions, propagating uncertainty and evaluating systematic error sources.
- Apply Hess's Law to calculate standard enthalpy changes via multi-step thermochemical cycles, including standard enthalpy of formation, combustion, and average bond-enthalpy routes, selecting the most reliable data source for a given target reaction.
R1.2 Energy Cycles in Reactions — Born-Haber (AHL)
- Construct and interpret Born-Haber cycles for ionic compounds to calculate lattice enthalpy indirectly from atomization, ionization, electron-affinity, and bond-dissociation enthalpy data, identifying the largest energy term and its physical origin.
- Apply enthalpy of solution cycles linking lattice enthalpy and enthalpy of hydration to explain and predict solubility trends of ionic salts, accounting for the competing effects of lattice energy and ion-dipole stabilization.
R1.3 Entropy and Gibbs Energy (AHL)
- Comprehend entropy as the measure of dispersal of energy and matter at the molecular level, predicting the sign of DeltaS for phase changes, dissolution, mixing, and gas-phase reactions from particle-count and freedom-of-motion arguments.
- Apply the Gibbs equation DeltaG = DeltaH minus T*DeltaS to calculate free energy changes at various temperatures, predict spontaneity, and determine the crossover temperature at which a reaction switches between spontaneous and non-spontaneous.
- Analyze the thermodynamic relationships DeltaG = minus RT ln K and DeltaG = minus nFE to connect free-energy spontaneity with equilibrium constants and electrochemical cell potentials, interpreting sign and magnitude in a unified framework (AHL).
5Reactivity 2 — How Much, How Fast, and How Far? 4 topics
R2.1 Stoichiometry and the Mole
- Apply molar mass, Avogadro's number, and stoichiometric ratios to calculate theoretical yield, percentage yield, and atom economy for multi-step synthetic routes from limiting-reagent analysis.
- Apply concentration and dilution relationships to design titration experiments, calculate molarity from primary standard data, and propagate volumetric uncertainties through to a reported analyte concentration.
R2.2 Reaction Kinetics
- Apply rate law expressions to determine reaction orders experimentally from initial-rate data, and distinguish zero-, first-, and second-order kinetics from the shape of concentration-time and rate-concentration graphs.
- Apply the Arrhenius equation k = Ae^(minus Ea/RT) to calculate activation energy from a ln k versus 1/T graph, interpret the physical meaning of the pre-exponential factor A and Ea, and predict how catalyst introduction alters both parameters (AHL).
- Analyze multi-step reaction mechanisms to identify the rate-determining step, verify consistency of the proposed mechanism with the experimentally observed rate law, and distinguish a reactive intermediate from a transition state (AHL).
R2.3 Chemical Equilibrium
- Apply the equilibrium constant expression Kc to calculate equilibrium concentrations via ICE tables, predict the direction of reaction from Q vs K comparison, and apply Le Chatelier's principle to predict shifts caused by concentration, pressure, and temperature changes.
- Apply the Kp/Kc relationship Kp = Kc(RT)^Deltan to interconvert pressure- and concentration-based equilibrium constants for gas-phase reactions, and evaluate how pressure changes shift heterogeneous equilibria (AHL).
R2.4 Proton Transfer — Acid-Base Equilibria
- Apply Ka, Kb, Kw, and pH/pOH relationships to calculate the pH of strong acids, strong bases, weak acids, weak bases, and salts undergoing hydrolysis, including amphiprotic species such as the hydrogen carbonate ion.
- Apply the Henderson-Hasselbalch equation to calculate buffer pH, evaluate buffer capacity as a function of component concentrations and pKa proximity, and design a buffer of specified pH from given weak acid/conjugate base pairs (AHL).
- Analyze acid-base titration curves to identify equivalence points, select appropriate pH indicators, calculate pH at the half-equivalence point (= pKa for weak acids), and distinguish strong-acid/strong-base from weak-acid/strong-base curve profiles (AHL).
6Reactivity 3 — What Are the Mechanisms of Chemical Change? 2 topics
R3.1 Electron Transfer — Redox Chemistry and Electrochemistry
- Apply oxidation-state rules to assign oxidation numbers in complex ions and organic molecules, identify oxidizing and reducing agents from half-equations, and balance redox equations by the half-reaction method in acidic and basic media.
- Apply standard electrode potentials from the electrochemical series to calculate standard cell potential E_cell, predict the spontaneity of redox reactions, and relate E to DeltaG and Kc using the relationship DeltaG = minus nFE (AHL).
- Apply the Nernst equation E = E_standard minus (RT/nF) ln Q to calculate cell potential under non-standard concentration conditions, predict how diluting a cell component affects spontaneity, and analyze concentration cells (AHL).
- Apply Faraday's laws to calculate the mass deposited or volume of gas liberated during electrolysis, predict electrode products from competing discharge reactions based on reduction potential and concentration, and relate this to the industrial chlor-alkali process.
R3.2 Organic Reaction Mechanisms
- Analyze SN1 and SN2 nucleophilic substitution mechanisms for halogenoalkanes — drawing complete curly-arrow mechanistic steps, comparing transition-state geometries, and predicting which pathway dominates based on substrate class, nucleophile strength, and solvent polarity (AHL).
- Apply E1 and E2 elimination reaction conditions to predict the major alkene product from a given halogenoalkane using Zaitsev's rule, and explain how substrate structure, base strength, and temperature control competition between substitution and elimination (AHL).
- Apply electrophilic addition mechanisms for alkenes — including Markovnikov regioselectivity arising from carbocation stability, anti-addition stereochemistry of Br2, and the role of the bromonium ion intermediate — drawing full curly-arrow mechanisms (AHL).
- Analyze electrophilic aromatic substitution reactions (nitration, Friedel-Crafts acylation and alkylation) using curly-arrow mechanisms that include the arenium-ion intermediate, and predict the directing effects of activating and deactivating substituents on benzene (AHL).
- Apply nucleophilic addition and addition-elimination mechanisms to carbonyl compounds — distinguishing aldehyde vs. ketone reactivity, and predicting products of reactions with HCN, LiAlH4, NaBH4, and Grignard-type reagents (AHL).
- Synthesize multi-step organic reaction pathways — selecting reagents, solvents, and conditions — to convert a given starting material into a target molecule, justifying each functional-group transformation and predicting all stereochemical outcomes (AHL).
7Tools for Chemistry — Practical and Analytical Skills 3 topics
T1 Experimental Uncertainty and Graphical Data Processing
- Apply absolute and percentage uncertainty rules for addition/subtraction and multiplication/division to propagate measurement errors through multi-step calculations, presenting results with appropriate significant figures and uncertainty bounds.
- Analyze experimental data graphically by constructing best-fit lines, determining gradients with uncertainty ranges from max/min gradient lines, linearizing non-linear relationships (e.g., ln k vs. 1/T for Arrhenius analysis), and classifying systematic vs. random error.
T2 Spectroscopic Identification (AHL)
- Apply infrared spectroscopy to identify functional groups by matching characteristic absorption wavenumbers (O-H, N-H, C=O, C-O, C-C) from a data table, and distinguish primary, secondary, and tertiary alcohol O-H stretching patterns.
- Analyze mass spectra to determine molecular formula from the M+ peak and identify structural fragments from characteristic m/z losses (loss of 15 for CH3, loss of 29 for CHO), proposing candidate structures consistent with the fragmentation pattern.
- Analyze 1H NMR spectra by assigning chemical shift values to proton environments, interpreting integration ratios to count equivalent protons, and applying the n+1 splitting rule to determine connectivity and propose constitutional structures of organic molecules (AHL).
- Synthesize IR, mass spectrometry, and 1H NMR spectral data to determine the complete structural formula of an unknown organic compound, constructing a coherent argument from all three data sources and systematically eliminating alternative structures (AHL).
T3 Internal Assessment — Individual Scientific Investigation
- Synthesize a focused research question into a complete experimental design — specifying independent, dependent, and controlled variables, justifying apparatus choices, addressing safety considerations, and predicting expected outcomes with mechanistic rationale.
- Evaluate the quality of an experimental investigation by identifying and quantifying the most significant sources of random and systematic error, proposing realistic improvements with mechanistic justification, and comparing results to published values with percentage-error analysis.
Scope
Included Topics
- Structure 1 — Atomic theory, electron configuration, sub-levels (spdf), emission spectra, and isotopes
- Structure 2 — Covalent, ionic, and metallic bonding; VSEPR; sp/sp2/sp3 hybridization; intermolecular forces and network solids
- Structure 3 — Periodic trends; IUPAC organic nomenclature and functional groups; stereoisomerism; transition-metal chemistry and complex ions
- Reactivity 1 — Thermochemistry: enthalpy (calorimetry, Hess's Law), Born-Haber energy cycles, entropy, and Gibbs energy spontaneity (AHL)
- Reactivity 2 — Stoichiometry and titration; chemical kinetics including rate laws and Arrhenius equation; chemical equilibrium (Kc, Kp); acid-base equilibria, buffer design, and titration curves (AHL)
- Reactivity 3 — Redox chemistry; galvanic and electrolytic cells; Nernst equation; organic reaction mechanisms including SN1/SN2, E1/E2, electrophilic addition, electrophilic aromatic substitution, and carbonyl chemistry (AHL)
- Tools for Chemistry — Experimental uncertainty propagation; graphical analysis; IR, mass spectrometry, and 1H NMR spectroscopic identification (AHL)
- Internal Assessment — Individual scientific investigation (10 hours minimum, 20% of final grade)
Not Covered
- Undergraduate-level quantum mechanics and full molecular orbital theory beyond hybridization
- Industrial process engineering and chemical plant design
- Biochemistry and metabolic pathways (covered in IB Biology HL)
- Nuclear fission and fusion beyond basic decay equations
- Polymer synthesis and materials science beyond introductory classification
- Environmental chemistry as a standalone option topic (removed in the 2025 syllabus restructure)
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