Today
Keyboard: 1–4 to answer, N for next.
Lab
One molecule, two representations. The flat drawing is what the exam is written in; the three-dimensional object is what the drawing is about. Translating between them is the whole skill — a wedge is a claim about space, a chair is what a hexagon actually looks like, and R/S is read off a drawing but defined by geometry. The toggle keeps the molecule and changes only how you are looking at it.
Click an atom or a bond to interrogate it · switch to 3-D to turn it over
Challenge
Press for a challenge. In bond-line it hides whatever it is asking about, then switches it on when you answer. In 3-D you manipulate the model and it grades the geometry.
What each view is for
- Bond-line — what the notation hides: implicit hydrogens, undrawn lone pairs, formal charge, R/S. Each is computed, so switching it on reveals the real answer.
- 3-D — what the drawing cannot show: dihedrals, torsional strain named interaction by interaction, axial vs equatorial, and the backside an SN2 nucleophile has to reach.
- Ring flip is a real geometric operation, not a flipped template — it reports what the flip costs in kcal/mol.
- Curved arrows — draw them on the flat structure and the legality is checked against it: an arrow from an atom with no lone pair, or into an atom that already has an octet, is refused with the count that refutes it.
- Molecules marked ◆ carry a 3-D challenge. Paste any SMILES to interrogate a structure from a problem set.
Course
The official section 49 calendar from the Fall 2026 syllabus and Canvas: every lecture, instructor, Loudon reading, assigned problem set, recitation quiz, and exam.
Organic chemistry is a small set of rules generating a huge combinatorial space. Store the rules and the geometry; derive the space. Everything below is structure → energy → electron movement → reactivity → synthesis.
Exam blocks
Chapters
Your library
Loudon is the assigned book. These local PDFs sit in ~/papers and are served read-only —
every link opens the actual page.
Loudon Chapter 1 exercises
All 49 exercises from the local solutions scan. Each card keeps its source, chapter, exercise type, ability, and answer-status meta labels; the link opens the original scanned page.
The nine abilities the course compresses into
Reference
The structured knowledge the questions are generated from. The Atlas reduces every reaction to the same eight fields; the tables and charts compare across them. Both are the same idea — an artifact you can read down a column as well as across a row — and both generate their own questions.
Every reaction reduced to the same eight fields. Read enough of them and reactions that looked unrelated collapse into six families — which is the point at which orgo starts feeling small.
Reaction map — read it both ways
Left to right is product prediction. Right to left is retrosynthesis. Same table.
Comparison tables and decision charts you can edit. An organizer here is also a question source — Practise this organizer sends you to the modes generated from the table on screen, and those questions read your edits, because both read the same object. The interesting questions are the ones that cut across a table rather than read one cell: what SN1 and E1 share, and the single thing they do not.
Progress
Percent correct is the least interesting number here. The useful one is the error-type distribution: which misconception keeps producing your wrong answers.