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)

A sensor experiment which can be applied to advanced undergraduate laboratory course in physical or analytical chemistry is described along with certain concepts like the demonstration of chemical sensing, preparation of thin films on a substrate, microtitration, optical determination of complex ion stoichiometry and isosbestic point. It is seen…

Describes a low-cost activity designed to help students visualize both the kinetic and the stoichiometric nature of chemical reactions at the particle level, by creating a flip book. Suggests ideas for evaluation of student work, and extension activities. (WRM)

Analyzes students' attempts to answer examination questions involving stoichiometry and chemical equilibrium and reports that the majority of the students do not fully understand either concept. Concludes that the main difficulty with these topics is that they are highly abstract and first taught to students before they have reached the stage of…

Investigates reasoning strategies students use in solving stoichiometric problems and explores the relation between these strategies and alternative conceptions, prior knowledge, and cognitive variables. Results show how stoichiometric relations produce conflicting situations for students leading to conceptual misunderstanding of certain concepts.…

Discusses an alternate path to teaching introductory stoichiometry based on research findings. The recommendation is to use problems that can be solved easily by rapid mental calculation as well as by pure logic. (AIM)

Describes a variation of typical introductory chemistry stoichiometry experiments in which the reaction is run in a modified 20-ounce plastic soda bottle. (WRM)

We present an alternative to a traditional first-year chemistry laboratory experiment. This experiment has four key features: students utilize stoichiometry, learn and apply principles of green chemistry, engage in authentic scientific inquiry, and discover why each part of a scientific lab report is necessary. The importance and essential…

Discusses problem-solving strategies and the successful strategy used to solve stoichiometric problems in general college chemistry courses. Reports that rereading problems, recalling a related concept, and reasoning deductively/inductively are the most heavily used strategies among 13 categories. (YP)

Results of a HyperCard method for assessing the performance of expert and novice high school chemistry students solving stoichiometric chemistry problems (balancing chemical equations) is reported. MANOVA results indicate significant difference between expert and novice students solving the five stoichiometric chemistry problems using…

Presents a method to teach stoichiometry where a problem is broken down into four factors and two cycles. Offers grams of known, moles of known, moles of unknown, and grams of unknown as the factors. Uses factor labeling as the second cycle. (MVL)