I do find one small quibble. A stoichiometry problem need not start at the house of a Starting Material and end at the house of a Product. For example: How many grams (moles, liters, etc.) of oxygen are required to completely oxidize a given amount of iron? Both oxygen and iron reside in the houses of the Starting Materials (on the same side of Mole River), and yet one must cross the Mole Street Bridge (use the stoichiometric ratio) to solve the problem. I plan to ask my students to critique their maps and think of ways to include such problems.

Literature Cited

1. Ault, A. Mole City: A Stoichiometric Analogy. J.Chem. Educ. 2006, 83, 1587–1588.

See author's reply.