C. Natural Systems
C.2 Structure and Reaction (Chemistry)
Course description
The free main text is OpenStax Chemistry 2e; Zumdahl works as an alternative.
- Atomic theory. Trace the atom from ancient philosophy to John Dalton's formal theory (1808), which proposed that matter is built from indivisible atoms combining in fixed ratios and made chemistry a quantitative science. Lavoisier's Traité élémentaire de chimie (1789) records oxygen chemistry replacing phlogiston theory and a new naming system; read it as a shift in explanatory framework rather than a clean break between alchemy and science, since earlier "chymistry" already shared much of its method. Follow the atomic models through Thomson's electron, Rutherford's nucleus, Bohr's orbits, and the quantum-mechanical atom.
- Periodic table and bonding. Study Mendeleev's periodic table (1869), arranged by atomic weight and properties well enough to predict undiscovered elements: it is a meta-pattern, an abstraction organizing chemical knowledge before anyone understood why it worked. Learn periodic trends, then ionic and covalent bonding, VSEPR molecular geometry, and, later, valence-bond and molecular-orbital theory. Kekulé proposed the benzene ring in 1865. His own account, told twenty-five years afterward at an 1890 celebration, of a dream about a snake biting its tail is disputed as history and is more useful as a prompt for how visual thinking works in chemistry than as an origin story to take literally. Grow copper sulfate or salt crystals to connect the macroscopic shape to the atomic arrangement.
- Thermochemistry and reaction mechanisms. Apply thermodynamics to chemical processes: enthalpy, entropy, and free energy explain why some reactions release heat and others absorb it. J. Willard Gibbs's 1875 papers on chemical equilibrium introduced free energy in its modern form. Measure the temperature rise of an acid-base neutralization to see an exothermic reaction directly, and study how mechanisms are inferred stepwise, as with SN1 and SN2 substitution in organic chemistry. Clayden's Organic Chemistry is the standard modern text.
- Organic chemistry and biochemistry. Move into the chemistry of carbon: hydrocarbons, functional groups, and typical reactions. Friedrich Wöhler's 1828 synthesis of urea from ammonium cyanate was later mythologized as the experiment that killed vitalism. It did not, Wöhler never claimed it did, and vitalist ideas about living matter persisted for decades afterward; Peter Ramberg traces how the myth was built. Read the story as a case study in how a field writes its own origin myths. In biochemistry, focus on proteins, nucleic acids, enzymes, and metabolism (Lehninger's Principles of Biochemistry or the Khan Academy chemistry-of-life material); Watson and Crick's roughly one-page 1953 Nature paper on the DNA double helix is worth reading in full to see how they argued from data to structure.
Checkpoints
Each checkpoint is tagged with the stage of the cycle it tests.| Stage | Checkpoint | Attempts |
|---|---|---|
skepticism | Explain phlogiston theory and the specific mass-gain evidence Lavoisier used against it. | Post the first attempt |
formalism | Predict periodic trends in ionization energy and atomic radius from electron configuration, then compute ΔG for a reaction to judge whether it is spontaneous at a given temperature. | Post the first attempt |
skepticism | State precisely what Wöhler's urea synthesis showed and what later textbooks added that he never claimed. | Post the first attempt |
formalism | Make a red-cabbage indicator, predict the color change for five household substances, and test them. | Post the first attempt |
abstraction | Explain why the periodic table is a compressed summary of quantum mechanics, linking back to C.1. | Post the first attempt |
Discussion
Proposed edits
Found an error, a missing idea, or a better source? Propose a change. A moderator reviews each proposal.Sources
- OpenStax. Chemistry 2e (free).
- "Atomic theory." Wikipedia.
- "Chemical thermodynamics." Wikipedia.
- Wöhler, Friedrich. "Ueber künstliche Bildung des Harnstoffs." Annalen der Physik und Chemie 88 (1828): 253–256.
- Ramberg, Peter J. "The Death of Vitalism and the Birth of Organic Chemistry: Wohler's Urea Synthesis and the Disciplinary Identity of Organic Chemistry." Ambix 47(3) (2000): 170–195.
- Watson, J. D. & Crick, F. H. C. "Molecular Structure of Nucleic Acids." Nature 171, 737–738 (1953).