This page presents combustion analysis data for the determination of empirical formulas. Its operation is quite straightforward. When you click on "New Problem" a window with information about a chemical compound and five possible answers will open. The first time you generate a question, you may have to "drag" tha window to a new position so that you can see the scoring table on the main page. Use the data provided to ascertain the empirical formula and then click on the circle in front of the answer. The results will appear in the table on the main window.