university levels of education Chemistry I — V
Five levels in one page, from counting the significant figures in a measurement to counting the isomers of an alkane — handmade, no ads, no sign-ups. One hundred topics and one thousand two hundred problems, every one of them carrying a full worked solution laid out step by step, a written lecture for every one of the hundred topics, and ten ways to study the same material. Start at whichever level you need; it is all one file, and the last entry opens the whole subject at once.
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Chemistry I
Matter, Atoms, the Mole and Equations. Where chemistry starts and where the habits are formed. Significant figures and the discipline of not claiming more precision than you measured, unit conversion including the cubed prefixes that catch everyone out, density and the temperature scales. Then the atom itself: protons, neutrons and electrons read off Z and A, isotopes, the weighted mean that gives an average atomic mass, and the electrons lost or gained to make an ion. The mole follows as the bridge between grams and particles — molar mass, moles both ways, Avogadro's number and the 22.4 litres a mole of gas occupies at STP. Then formulas from percentage composition, empirical to molecular, and hydrates with their water counted in. It closes on the balanced equation every later calculation depends on, reaction types, net ionic equations and the solubility rules that predict a precipitate. Twenty topics, 240 problems. Every topic is a full lecture: a summary, sections of explanation including how the problems are solved and where they go wrong, a formula table, worked examples with the reason for every step, practice with hints, a quiz, defined terms, and three problems left unsolved for the reader — all typeset as real mathematics by KaTeX, from ion charges to equilibrium arrows, readable one lecture at a time or as one continuous scroll.
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Chemistry II
Stoichiometry, Solutions and Gases. The arithmetic of reactions, and the place most marks are lost. Mole ratios read off the coefficients, mass-to-mass calculations through the grams-moles-ratio-moles-grams chain, the limiting reagent found by dividing moles by coefficient, and percentage yield. Then concentration in every form it is asked for: molarity, dilution by c1V1 = c2V2, mass percentage and parts per million, and the molality that uses kilograms of solvent and so survives a temperature change. The gas laws follow — Boyle, Charles, the combined law and PV = nRT solved for each of its unknowns — then partial pressures and mole fractions, gas stoichiometry, d = PM/RT in both directions and Graham's law of effusion. It ends on solution stoichiometry: titration to an endpoint, the mass of a precipitate, percentage purity and serial dilution. Twenty topics, 240 problems. Every topic is a full lecture: a summary, sections of explanation including how the problems are solved and where they go wrong, a formula table, worked examples with the reason for every step, practice with hints, a quiz, defined terms, and three problems left unsolved for the reader — all typeset as real mathematics by KaTeX, from ion charges to equilibrium arrows, readable one lecture at a time or as one continuous scroll.
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Chemistry III
Structure, Bonding and Thermochemistry. Why atoms behave as they do. Photon energy from both E = hf and E = hc/lambda, the Bohr levels and the energy of a jump between them, quantum numbers and the capacity they set, and electron configurations filled by energy rather than by shell number. Then the periodic trends that follow: atomic radius down a group and across a period, ionisation energy, electronegativity differences and the effective nuclear charge behind all three. Bonding comes next — ionic against covalent read off that difference, Lewis structures counted before they are drawn, formal charge, and enthalpy of reaction from bonds broken and formed — then VSEPR shapes, bond angles squeezed by lone pairs, hybridisation counted from electron domains, and whether the molecule's dipoles cancel. It closes on heat: q = mcdT, calorimetry, Hess's law and enthalpies of formation. Twenty topics, 240 problems. Every topic is a full lecture: a summary, sections of explanation including how the problems are solved and where they go wrong, a formula table, worked examples with the reason for every step, practice with hints, a quiz, defined terms, and three problems left unsolved for the reader — all typeset as real mathematics by KaTeX, from ion charges to equilibrium arrows, readable one lecture at a time or as one continuous scroll.
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Chemistry IV
Kinetics, Equilibrium, Acids and Bases. How fast, how far, and how acidic. Average rates, rate laws and the order that decides how a rate answers a change in concentration, the first-order half-life that ignores concentration entirely, and the Arrhenius equation behind the effect of heating. Then equilibrium: the constant as products over reactants raised to the coefficients, ICE tables, the reaction quotient Q and the direction it implies, and Le Chatelier's principle applied to pressure, temperature, concentration and the catalyst that changes nothing. Acids and bases follow — pH and pOH, strong acids and bases that ionise completely, weak acids through the square-root shortcut and weak bases through percentage ionisation — then buffers by Henderson-Hasselbalch, what happens when strong acid is added to one, equivalence volumes and matching an indicator to the curve. It ends on the solubility product, the common ion effect and predicting a precipitate. Twenty topics, 240 problems. Every topic is a full lecture: a summary, sections of explanation including how the problems are solved and where they go wrong, a formula table, worked examples with the reason for every step, practice with hints, a quiz, defined terms, and three problems left unsolved for the reader — all typeset as real mathematics by KaTeX, from ion charges to equilibrium arrows, readable one lecture at a time or as one continuous scroll.
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Chemistry V
Thermodynamics, Electrochemistry and Beyond. The questions that decide whether a reaction happens at all. Entropy change, Gibbs free energy and the unit trap inside dG = dH - TdS, the temperature at which a reaction turns spontaneous, and the link dG = -RT ln K. Then electrochemistry: oxidation numbers assigned from the reliable elements outward, oxidising and reducing agents that do the opposite of what their names suggest, cell potential as cathode minus anode, and the Nernst equation away from standard conditions. Electrolysis puts Faraday's laws to work in both directions — charge to electrons to moles to mass, the time a given deposit demands, the gas volumes collected at each electrode, and dG = -nFE. It finishes on the nucleus, with alpha and beta decay, half-lives, mass defect at 931.5 MeV per u and radiometric dating, then a first pass through organic chemistry: alkanes and alkenes, functional groups, structural isomers and degrees of unsaturation. Twenty topics, 240 problems. Every topic is a full lecture: a summary, sections of explanation including how the problems are solved and where they go wrong, a formula table, worked examples with the reason for every step, practice with hints, a quiz, defined terms, and three problems left unsolved for the reader — all typeset as real mathematics by KaTeX, from ion charges to equilibrium arrows, readable one lecture at a time or as one continuous scroll.
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The whole of Chemistry
All five courses in one reader — one hundred lectures across twenty-five chapters, from counting the significant figures in a measurement to counting the structural isomers of an alkane. Every lecture explains its topic in full: sections of prose with the chemistry typeset by KaTeX — formulas with real subscripts, ion charges as superscripts, reaction and equilibrium arrows — a section on how the problems are solved and another on where they go wrong, a formula table, three worked examples with the reason for every step spelled out, four practice problems with hints and answers, a three-question quiz, defined terms, and three problems left unsolved for the reader to do on their own. Nineteen ways to study the same material, from a plain reading mode and a continuous view that carries a whole course end to end in one scroll, to drills, quizzes, flashcards, formula sheets, a searchable index, progress tracking and print. Forty-six colour palettes, twelve layouts and custom colours throughout.
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