Chemistry
The core high-school chemistry course, from atoms and bonding through the mole, gases, solutions, and acids and bases, as animations.
12 units · 118 topics · 535 questions
What matter actually is, how chemists sort it, and the counting and measuring skills every later unit leans on.
1.1 States of Matter and the Particle Model · 1.2 Classifying Matter: Pure Substances and Mixtures · 1.3 Elements, Compounds, and Mixtures · 1.4 Physical Properties of Matter · +6 more
How a handful of scientists figured out what's inside an atom, and how the periodic table turns that structure into a predictive map.
2.1 Dalton's Atomic Theory · 2.2 Thomson's Discovery of the Electron · 2.3 Rutherford's Gold Foil Experiment · 2.4 The Bohr Model of the Atom · +10 more
Why atoms give up, share, or pool their electrons, and how that single choice decides a compound's shape, polarity, and physical behavior.
3.1 Why Atoms Bond: The Octet Rule · 3.2 Ionic Bonding: Electron Transfer · 3.3 Properties of Ionic Compounds · 3.4 Covalent Bonding: Electron Sharing · +9 more
The rulebook that turns a formula into a name and a name back into a formula, for ionic compounds, covalent compounds, and acids.
4.1 Naming Binary Ionic Compounds · 4.2 Writing Formulas for Ionic Compounds · 4.3 Polyatomic Ions and Their Formulas · 4.4 Naming Compounds with Polyatomic Ions · +4 more
Reading a chemical equation as a real rearrangement of atoms, balancing it correctly, and sorting reactions into the patterns they actually follow.
5.1 Reading and Writing Chemical Equations · 5.2 Balancing Chemical Equations · 5.3 Conservation of Mass in a Reaction · 5.4 Synthesis (Combination) Reactions · +6 more
The counting unit that lets chemists weigh out atoms and molecules on a balance, and the arithmetic that turns a balanced equation into real masses.
6.1 Why Chemists Count in Moles · 6.2 Avogadro's Number as a Counting Unit · 6.3 Converting Between Moles and Number of Particles · 6.4 Molar Mass · +8 more
How gas particles behave according to kinetic theory, and the laws that let you predict a gas's pressure, volume, and temperature from any two.
7.1 Kinetic Molecular Theory of Gases · 7.2 Gas Pressure and How It's Measured · 7.3 Boyle's Law · 7.4 Charles's Law · +6 more
What actually happens when one substance dissolves into another, and how chemists measure and control exactly how concentrated a solution is.
8.1 Solutions, Solutes, and Solvents · 8.2 Like Dissolves Like · 8.3 Factors That Speed Up Dissolving · 8.4 Saturated, Unsaturated, and Supersaturated Solutions · +5 more
What makes a solution acidic or basic, how the pH scale measures it, and how a titration finds an unknown concentration one drop at a time.
9.1 Properties of Acids and Bases · 9.2 The Arrhenius and Bronsted-Lowry Definitions · 9.3 Strong versus Weak Acids and Bases · 9.4 The pH Scale · +5 more
A first, mostly qualitative look at the energy a reaction releases or absorbs, what speeds a reaction up, and what it means for a reaction to reach balance.
10.1 Exothermic and Endothermic Reactions · 10.2 Enthalpy and Reaction Energy Diagrams · 10.3 Measuring Heat with a Calorimeter · 10.4 Specific Heat Capacity · +5 more
What happens inside an unstable nucleus, the radiation it gives off, and how splitting or fusing nuclei releases energy on a completely different scale.
11.1 Radioactivity and the Unstable Nucleus · 11.2 Alpha, Beta, and Gamma Decay · 11.3 Writing Nuclear Equations · 11.4 Half-Life · +3 more
Why carbon builds more compounds than every other element combined, and the naming and shape rules that organize its endless chains and rings.
12.1 Why Carbon Forms So Many Compounds · 12.2 Naming Simple Alkanes · 12.3 Alkenes, Alkynes, and Multiple Bonds · 12.4 Structural and Skeletal Formulas · +3 more