Physical chemistry examines the physical principles underlying chemical systems. It draws on mathematics and physics to explain why reactions occur, how fast they proceed, and what determines the stability of molecular structures. Core topics include thermodynamics, chemical kinetics, quantum mechanics, and spectroscopy.

Thermodynamics describes the energy changes and spontaneity of reactions through quantities such as enthalpy ($H$), entropy ($S$), and Gibbs free energy ($G$). The relationship $\Delta G = \Delta H - T \Delta S$ determines whether a process is thermodynamically favourable at a given temperature. Chemical kinetics, by contrast, concerns the rate at which reactions occur and the mechanisms by which they proceed.

Consider a reaction with $\Delta H = -92.2 \text{ kJ mol}^{-1}$ and $\Delta S = -198.7 \text{ J K}^{-1} \text{mol}^{-1}$ at $T = 298 \text{ K}$. Converting entropy to kJ: $\Delta S = -0.1987 \text{ kJ K}^{-1} \text{mol}^{-1}$. Applying the equation:

$\Delta G = -92.2 - (298)(-0.1987) = -92.2 + 59.2 = -33.0 \text{ kJ mol}^{-1}$

Since $\Delta G < 0$, the reaction is spontaneous under these conditions.

University-level physical chemistry notes covering thermodynamics, kinetics, quantum chemistry, and spectroscopy.

• Thermodynamics: Enthalpy, entropy, Gibbs free energy, phase equilibria
• Kinetics: Rate laws, reaction mechanisms, catalysis, Arrhenius equation
• Quantum Chemistry: Wave functions, Schrodinger equation, molecular orbitals
• Spectroscopy: IR, UV-Vis, NMR, mass spectrometry

• General chemistry (first-year university level)
• Calculus (differentiation, integration, differential equations)
• Linear algebra (matrices, eigenvalues)
• Basic physics (mechanics, thermodynamics)

Start with the introductory sections to build foundational knowledge, then progress to more advanced topics. Each section includes worked examples and practice problems.

Use the sidebar to browse topics, or start with the introductory pages linked from the sidebar.

Each section includes:

• Detailed explanations of key concepts
• Worked examples with step-by-step solutions
• Practice problems with answers
• Common pitfalls and how to avoid them
• Connections to other areas of physical chemistry

1. Build a strong foundation: Ensure you understand the basic concepts before moving to advanced topics
2. Practice regularly: Physical chemistry requires active practice, not just reading
3. Work through derivations: Practice deriving equations from first principles
4. Use mathematical tools: Familiarise yourself with calculus and linear algebra techniques
5. Connect theory to experiment: Relate theoretical concepts to experimental observations