Physical chemistry – A Level AQA Chemistry revision notes

What this topic covers

Physical chemistry has 12 subtopics, including:

• Atomic structure
• Amount of substance
• Bonding
• Energetics
• Kinetics
• Chemical equilibria, Le Chatelier’s principle and Kc

Physical chemistry lessons by subtopic

68 lessons, grouped by subtopic.

Atomic structure

• Unveiling the Atom: A Journey Through Time: Explore the historical development of atomic theory and identify the fundamental particles that constitute an atom.
• Atomic Structure: Mass Number, Isotopes, and Calculations: Explore mass number, atomic number, isotopes, and relative atomic mass calculations.
• Mass Spectrometry: Principles and Interpretation: Understand the principles of time of flight mass spectrometry and interpret simple mass spectra.
• Ionisation Energy Explained: Understand the definition of first ionisation energy and learn to write equations for first and successive ionisation energies.
• Electron Configuration Evidence: Explore how first and successive ionisation energies provide evidence for electron configuration in Period 3 and Group 2 elements.

Amount of substance

• Balancing Equations and Stoichiometric Calculations: Learn to balance chemical equations and perform calculations involving masses, gas volumes, solution concentrations, and titrations.
• Percentage Yield and Atom Economy (Part 1/2): Explore percentage yield and atom economy calculations, including real-world applications such as determining the purity of substances and analysing experimental results.
• Percentage Yield and Atom Economy (Part 2/2): Explore percentage yield and atom economy calculations, including real-world applications such as determining the purity of substances and analysing experimental results.
• Relative Atomic Mass and Relative Molecular Mass: Learn about relative atomic mass (Ar), relative molecular mass (Mr) and relative formula mass.
• Introduction to the Ideal Gas Equation: Learn about the ideal gas equation, its variables in SI units, and how to use it in calculations. You will be provided the gas constant R.
• The Mole & Avogadro's Constant: An introduction to the mole concept, Avogadro's constant, and their applications in chemistry.
• Moles, Mass & Mr Calculations: Learn how to calculate moles using mass and Mr, with plenty of practice questions.
• Concentration Calculations: Understand concentration in mol dm-3 and perform calculations involving concentration, volume, and amount of substance.

Bonding

• Predicting Ion Charges & Formula Construction: Learn how to predict ion charges based on the periodic table and construct formulas for ionic compounds.
• Ionic Lattices & Compound Ions: Understand the electrostatic forces in ionic lattices and learn about common compound ions.
• Crystal Structures: Ionic, Metallic & Molecular (Part 1/2): Explore ionic, metallic, and molecular crystal structures, including examples like sodium chloride, magnesium, ice and iodine. Relate structure and bonding to melting point and conductivity. Draw diagrams of crystal structures.
• Crystal Structures: Ionic, Metallic & Molecular (Part 2/2): Explore ionic, metallic, and molecular crystal structures, including examples like sodium chloride, magnesium, ice and iodine. Relate structure and bonding to melting point and conductivity. Draw diagrams of crystal structures.
• Giant Covalent Structures: Diamond & Graphite: Investigate macromolecular (giant covalent) structures, focusing on diamond and graphite. Relate their structure and bonding to their physical properties, including melting point and conductivity. Draw diagrams of diamond and graphite.
• Energy Changes & States of Matter: Explain the energy changes associated with changes of state. Consider this in the context of different types of bonding.
• Intermolecular Forces: Dipoles and Van der Waals: Explore permanent dipole-dipole forces, induced dipole-dipole (van der Waals) forces, and their influence on molecular interactions. Understand how these forces arise and affect molecular properties.
• Hydrogen Bonding: Strength and Effects: Examine hydrogen bonding, its effects on melting and boiling points and how it affects the properties of specific compounds like water, particularly focusing on ice density and anomalous boiling points.

Energetics

• Enthalpy Change: Definitions: Learn the definitions of standard enthalpy of combustion (∆cHƟ) and standard enthalpy of formation (∆fHƟ).
• Enthalpy Changes: Explore endothermic and exothermic reactions, enthalpy change (∆H), and standard conditions.
• Mean Bond Enthalpy: Definitions: Define mean bond enthalpy and understand its significance in thermochemical calculations.
• Calculating Enthalpy Changes Using Mean Bond Enthalpies: Use mean bond enthalpies to calculate approximate enthalpy changes (∆H) for reactions in the gaseous phase and explore the limitations of this method.
• Hess's Law Calculations: Master the calculations involved in Hess's Law using enthalpies of combustion and formation.
• Hess's Law: Experimental Applications: Explore the practical applications of Hess's Law with thermal decomposition of sodium bicarbonate and hydration of magnesium and copper sulfates.
• Calorimetry Calculations: q=mcΔT and Molar Enthalpy Change: Learn how to calculate the heat change (q) using q=mcΔT and relate it to molar enthalpy changes. Understand the meaning of each variable and perform related calculations.
• Enthalpy Change Examples: Dissolution, Neutralization, Displacement, and Combustion: Explore various examples of enthalpy changes, including the dissolution of potassium chloride and sodium carbonate, neutralization of NaOH with HCl, displacement reaction between CuSO4 and Zn, and combustion of alcohols.

Kinetics

• Temperature's Effect on Reaction Rate: Explore how temperature affects reaction rates, using the Maxwell-Boltzmann distribution and practical investigations.
• What are Catalysts?: An introduction to catalysts, their definition, and how they speed up reactions.
• Maxwell-Boltzmann Distribution: Explore the Maxwell-Boltzmann distribution of molecular energies in gases and how temperature affects the distribution curve.
• Collision Theory and Activation Energy: Explore the basics of collision theory, the importance of activation energy, and why not all collisions lead to reactions.
• Concentration, Pressure, and Reaction Rates: Explore how concentration and pressure affect reaction rates by influencing collision frequency.

Chemical equilibria, Le Chatelier’s principle and Kc

• Kc Expressions and Calculations: Learn how to construct Kc expressions, calculate Kc values, and perform related calculations.
• Factors Affecting Kc: Explore the effects of temperature on Kc and understand what does NOT influence Kc.
• Equilibrium: The Dynamic Balance: Explore the concept of dynamic equilibrium, including forward and reverse reaction rates and constant concentrations.
• Le Chatelier's Principle: Shifting Equilibria: Learn about Le Chatelier's principle and how changes in temperature, pressure, and concentration affect equilibrium position in homogeneous reactions. Also, how catalysts influence equilibrium.
• Industrial Equilibria: Finding the Balance: Understand the compromise conditions (temperature and pressure) used in industrial processes for reversible reactions.

Oxidation, reduction and redox equations

• Oxidation States: Learn how to determine the oxidation state of elements in compounds and ions using established rules.
• Half-Equations and Redox: Explore the concepts of oxidation and reduction, and learn how to write and combine half-equations to form overall redox equations.

Thermodynamics (A-level only)

• Enthalpy Definitions: Learn to define enthalpy of formation, ionisation energy, enthalpy of atomisation, bond enthalpy, electron affinity and lattice enthalpy (dissociation and formation).
• Born-Haber Cycles and Lattice Enthalpy: Construct Born-Haber cycles to calculate lattice enthalpies and other enthalpy changes. Compare experimental lattice enthalpies with theoretical values to predict covalent character.
• Enthalpy of Solution: Calculate enthalpy changes using Born-Haber cycles, lattice enthalpies, and enthalpies of hydration for ionic compounds in solution.
• Introduction to Gibbs Free Energy: Explore entropy, enthalpy, and feasibility in chemical reactions. Understand the limitations of enthalpy and the importance of entropy.
• Gibbs Free Energy Calculations: Learn to calculate entropy changes, and use the Gibbs free energy equation to determine how feasibility changes with temperature.

Rate equations (A-level only)

• Introduction to Rate Equations: Learn about rate equations, including order of reaction, rate constant, and the general form of the rate equation.
• Rate Equation Calculations: Practice calculations using the rate equation and explore the effect of temperature on the rate constant.
• The Arrhenius Equation: Understand and apply the Arrhenius equation, including calculations and graphical analysis.
• Concentration-Time Graphs and Initial Rates: Learn how to use concentration-time graphs and initial rate data to determine reaction rates.
• Orders of Reaction and Rate Equations: Explore how to determine the order of reaction with respect to reactants and derive the rate equation.
• Reaction Mechanisms and Rate-Determining Step: Understand how rate equations and reactant orders provide insights into reaction mechanisms and the rate-determining step.

Equilibrium constant Kp for homogeneous systems (A-level only)

• Kp and Partial Pressures: Learn how to calculate partial pressures and construct Kp expressions for homogeneous gaseous equilibria.
• Kp Calculations and Le Chatelier's Principle: Master Kp calculations and use Le Chatelier's principle to predict the effects of changing conditions on equilibrium and Kp.

Electrode potentials and electrochemical cells (A-level only)

• Electrochemical Cells: Principles and Applications: Explore how electrode reactions generate electric current in electrochemical cells, calculate EMF using electrode data, and classify cells as rechargeable or non-rechargeable.
• Lithium Cells: Reactions and Function: Analyse the electrode reactions in lithium cells and understand how these reactions contribute to the cell's function as a commercial energy source.
• Fuel Cells: Hydrogen-Oxygen and Societal Impact: Investigate the electrode reactions in alkaline hydrogen-oxygen fuel cells, compare them with other cells, and evaluate the benefits and risks of using these cells in society.
• Electrode Potentials and Redox Reactions: Learn about standard electrode potentials, how to use them to predict redox reactions, and understand the importance of standard conditions.
• Electrochemical Cells: EMF and Representation: Understand how electrochemical cells work, how to calculate their EMF, and how to represent them using IUPAC conventions.
• Practical: Measuring EMF of an Electrochemical Cell: This lesson focuses on the practical aspects of measuring the EMF of an electrochemical cell, covering the required practical 8.

Acids and bases (A-level only)

• Titration Calculations and Curve Shapes: Learn to perform titration calculations and understand the shapes of typical pH curves for different acid-base combinations.
• Indicators and Weak/Strong Acid-Base Reactions: Explore how to select appropriate indicators using pH curves and investigate pH changes in reactions involving weak acids and strong bases.
• Understanding Ka and Acid Dissociation: Explore the concept of weak acids, their dissociation in solution, and the meaning of the acid dissociation constant, Ka.
• Calculations with Ka and pKa: Learn how to calculate pH using Ka, convert between Ka and pKa, and apply these concepts to weak acid solutions.
• Brønsted-Lowry Acids and Bases: Learn about the Brønsted-Lowry definitions of acids and bases as proton donors and acceptors, and explore their role in acid-base equilibria.
• Understanding and Calculating pH: Learn about the pH scale, how it relates to hydrogen ion concentration, and how to calculate pH for strong acids.
• Introduction to Kw and Water's Dissociation: Explore the dissociation of water and the concept of the ionic product of water (Kw).
• Kw Calculations and Temperature Dependence: Learn how to use Kw to calculate the pH of strong bases and understand how Kw varies with temperature.

Revise Right Mocks '26

AQA A-Level Chemistry mock draft, 26–31 Oct. Draft coverage: Chemistry 7405/1 · Paper 1. Reviewed for an original-practice sitting; check student availability before registering. Marking and results will follow later, after separate approval. Eligible new accounts receive a five-day Pro trial when signup email verification completes. Previous trials keep their original expiry. After expiry, new papers need Pro unless you have an explicitly confirmed free sitting offer for this event. That offer adds no Pro time or AI learning. Saved attempts and released results remain readable. No card or automatic charge.

More in this course

Go back to the full A Level AQA Chemistry topic list, or practise this topic with past-paper questions.