An open-access, Web-based mnemonic game is described whereby introductory chemistry knowledge is tested using mahjong solitaire game play. Several tile sets and board layouts are included that are themed upon different chemical topics. Introductory tile sets can be selected that prompt the player to match element names to symbols and metric prefixes to powers of 10. More advanced tile sets are available that require the player to assign oxidation numbers and electronic configurations, predict precipitation, and recognize weak and strong acids and bases. Chemical Mahjong is intended for introductory chemistry students. Adobe Flash Player 10.1+ must be installed to run this application. (Contains 2 figures.)