Students' inaccurate ideas about what is represented by chemical equations and concepts underlying stoichiometry are well documented; however, there are few classroom-ready instructional solutions to help students build scientifically accurate ideas about these topics central to learning chemistry. An intervention (two inquiry-based activities)…

This article explores the time it takes for a liquid to drain from a cylindrical container through a hole in the bottom. Using dimensional analysis and some thought experiments this time is determined and Torricelli's law derived as a consequence. Finally, the effect of pouring liquid into the container as it drains is considered.

Discusses how chemists describe an amount of material and provides a visual representation for the solution of typical stoichiometry problems. (YDS)

Teachers and students alike report difficulties with the measurement unit called mole. This article tries to demonstrate that mole and the corresponding quantity are not exceptional. Mole lacks the context of a given amount because the unit measures the relative number of atoms compared with those present in a standard. Discusses history of…

Indicates that the concept of definite proportions or constant composition should be introduced with qualification. Presents arguments against the Law of Definite Proportions and cites examples in the areas of solid solutions, compounds of the transition and inner transition elements, and in some compounds of the representative elements. (GS)

Presents experiments involving the analysis of commercial products such as carbonated beverages and antacids that illustrate the principles of acid-base reactions and present interesting problems in stoichiometry for students. (JRH)

Discusses an instructional strategy in which stoichiometric reactions are presented in terms of a recipe. Solutions for two different stoichiometric problems are included. (JN)

Reviews the history of the stoichiometric term "equivalent" and examines its relevance over the last hundred years. (MLH)

Describes an experiment presented to students as a problem in determining the stoichiometry of "copper iodide" to decide whether it is cuprous iodide or cupric iodide. The experiment illustrates stoichiometry principles, providing experiences with laboratory techniques and numerical computation. Detailed outline (written for student use) is…

Shows how the computer software programs Mathematica and Maple can be used to obtain chemical equations to represent the stoichiometry of a reacting system. Specific examples are included. Contains 10 references. (DKM)

Pictorial analogies that demonstrate concepts of amounts allow instructors to teach that in stoichiometric problems, the number--or moles--of molecules of a chemical is what matters, even though it must be measured in masses or volumes. Analogies to stoichiometric relationships include the ratio of four wheels to one body in making wagons and…

Presents a solution to the problem of finding the source of extra reducing equivalents, and accomplishing the stoichiometry of glucose oxidation reactions. Discusses the citric acid cycle and glycolysis. (CW)

Discusses a method to solve problems in stoichiometry which can also be applied to other problems involving relationships between constituents in a chemical reaction. Students with little prior knowledge of chemistry can successfully use the method. (Author/SK)

Presents an activity that is suitable for a high school chemistry or introductory college chemistry lab in which students create their own Fizzie-style carbonated beverage and use stoichiometry to calculate the correct mix of citric acid and baking soda. (Author/ASK)