Stoichiometry
(see description below the applet)
One of the first numerical problems encountered in introductory chemistry is that of "limiting reagents". The applet does not approach or solve the problem as it would be done with paper and pencil, on the blackboard, or in the textbook. Rather, it serves as a supplement to such calculations, providing imagery that helps students see beyond a rote mathematical procedure. In lecture, the instructor may work through the problem on the blackboard, referring to the applet as a constant visual reminder of what is being calculated and why. Outside lecture, students may use the applet while solving problems, to generate and check intermediate results and help them discover and correct their own mistakes.
For more information on in-class uses of this applet.