About these exercises

Each exercise gives you a compound name. Draw its structure in the editor and press Check answer. The checker compares the molecule you drew with the answer as a chemical graph (atoms, bonds, charges and, where the exercise asks for it, stereochemistry), so a correct structure is accepted however it is drawn, rotated or numbered. It does not compare pictures. Read exactly how answers are graded.

There are currently 50 exercises covering alkanes and cycloalkanes, alkenes and alkynes, haloalkanes, alcohols and ethers, aldehydes and ketones, carboxylic acids and derivatives, amines and nitriles, benzene derivatives, stereochemistry: e/z and r/s. Every name has been checked against its structure with two independent tools (the OPSIN name parser and PubChem); see the topic guides for the naming rules behind them. Your progress is stored only in this browser.