Chemistry lessons where students get their hands on the chemistry: mix, heat, dilute, shift the equilibrium and check the numbers. As with the physics lessons, each lesson is a single page that opens on a phone or a computer, with nothing to install.
States of matter, properties of matter, substances and mixtures, and how to separate a mixture: filtration, decanting, distillation.
From Dalton to Bohr by way of Thomson and Rutherford; atomic number, mass, isotopes and electron configuration.
How the table is laid out, groups and periods, and the properties that rise and fall across it: radius, ionisation energy, electronegativity.
Ionic, covalent and metallic bonds, molecular shape, polarity and the intermolecular forces that decide the boiling point.
Acids, bases, salts and oxides, indicators and the pH scale, neutralisation and acid rain.
Types of reaction, balancing equations, the mole, molar mass, limiting reagent, yield and purity.
Solubility and solubility curves, concentration, dilution, mixing solutions, titration and colligative properties.
Reactions that give out and take in heat, enthalpy, Hess's law, bond energy and the energy content of fuels.
Rate of reaction, effective collisions, activation energy, catalysts and the effect of temperature, concentration and surface area.
Reactions that go both ways, the equilibrium constant, Le Chatelier's principle, pH and pOH, hydrolysis and solubility product.
Redox, cells and standard potential, batteries, corrosion and electrolysis.
Carbon and its chains, hydrocarbons, functional groups and IUPAC naming.
Structural, geometric and optical isomerism: molecules with the same formula and different properties.
Substitution, addition, elimination, oxidation and combustion; esterification and saponification.
Plastics, rubber and recycling; carbohydrates, lipids and proteins; crude oil and biofuels.
Each step will have a drawing that responds to the controls: colliding particles, balloons filling up, a beaker changing colour. The numbers on screen use the same formulas as the text.
Questions that ask you to try things: ‘double the concentration’, ‘heat the system’, ‘take away some product and see which way the equilibrium goes’.
10 per step (4 basic, 4 intermediate and 2 challenges), with the worked solution hidden until you click.
At the end, challenges that mix the steps, five ENEM-style questions (Brazil's national secondary-school exam) with references to real exam questions, and a sheet with every formula in the lesson.