Chemistry Notes & Lessons

Chemistry Notes helps you learn chemistry step by step: clear chemistry notes for high school and first-year general chemistry, with 80 topics in 16 sections, 53 original diagrams, 132 worked examples and 177 practice questions.
From atoms and the periodic table to equilibrium, acids and bases and electrochemistry, every lesson is written in plain language and works offline.

Each topic explains the ideas first, then the formulas and chemical equations. Worked examples use real numbers, and notes point out common mistakes.

What you will learn

• Matter and Measurement: SI units, significant figures and unit conversions
• Atoms and Electrons: atomic structure, isotopes, atomic spectra, quantum numbers, orbitals and electron configurations
• The Periodic Table: periodic trends (atomic radius, ionization energy, electronegativity) and element families
• Chemical Bonding: ionic, covalent and metallic bonds, Lewis structures, VSEPR shapes, hybrid orbitals, polarity and intermolecular forces
• Naming Compounds: ionic compounds, molecular compounds and acids
• The Mole and Stoichiometry: molar mass, empirical formulas, balancing chemical equations, limiting reactant and percent yield
• States of Matter: gas laws, the ideal gas law, partial pressures, kinetic theory, crystal structures and phase diagrams
• Solutions: solubility, concentration units, dilution and titration calculations, colligative properties
• Thermochemistry and Thermodynamics: calorimetry, enthalpy, Hess's law, entropy and Gibbs energy
• Chemical Kinetics: rate laws, half-life, activation energy, catalysts and mechanisms
• Chemical Equilibrium: equilibrium constants, ICE tables, Le Chatelier's principle and solubility equilibria
• Acids and Bases: the pH scale, weak acids and bases, buffers and titrations
• Redox and Electrochemistry: oxidation numbers, balancing redox equations, galvanic cells, electrode potentials, the Nernst equation and electrolysis
• Nuclear Chemistry: binding energy, radioactive decay, half-life and dating, fission and fusion
• Organic Chemistry Basics: naming hydrocarbons, functional groups, isomers and reactions
• Reference Tables: constants (CODATA 2022), atomic weights, common ions, solubility rules, Ka and Kb values, thermodynamic data and reduction potentials

Features
• 80 chemistry topics in 16 sections, including 7 reference tables
• 53 original diagrams: orbital shapes, the periodic table, VSEPR shapes, phase diagrams, energy profiles, titration curves, a galvanic cell and more
• 132 worked examples with step-by-step numbers
• 177 practice questions with tap-to-reveal answers
• Formulas with the meaning and unit of each symbol
• Search all chemistry notes from the home screen
• Dark mode
• Works offline, no account needed
• Available in 8 languages: English, Español, Português, Français, Deutsch, العربية, हिन्दी and Bahasa Indonesia

Who it is for
• High school students who want to learn chemistry or review it before tests; useful when revising for AP, A-level or IB Chemistry
• College and university students taking introductory general chemistry
• Teachers and tutors who want clear chemistry notes with diagrams to share

Chemistry Notes is an independent study aid. Content is checked against the OpenStax Chemistry 2e textbook, IUPAC recommendations, NIST reference data (CODATA 2022) and the CRC Handbook of Chemistry and Physics. It is not affiliated with any exam board, textbook publisher or standards body.