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The connection between success in introductory college chemistry and high school chemistry content coverage is explored by taking stoichiometry as the parameter. The results suggest stoichiometry to be the one chemistry topic among a group to be an important predictor of college chemistry performance and the predicted grade of the students who reported a heavy emphasis on stoichiometry was 2.6 points higher than their peers who reported studying stoichiometry for a few weeks or a month.

A series of synthetic chemistry experiments suitable for advanced undergraduate chemistry students learning about catalytic and stoichiometric reaction methodologies is described. Preparation of aniline derivatives with HOOH as the oxidant and FeCl(sub.2)py(sub.4)(super.+) as catalyst is covered. The students are to think about design of cost-effective and environmentally sound synthetic routes and about sustainable global growth. Students can learn about the differences between the catalytic reactions and the stoichiometric reactions.

Langmuir and Freundlich adsorption and the stoichiometric displacement model (SDM), an equilibrium model for proposed for reversed-phase liquid chromatography (RPLC), are discussed. The SDM is conceptualized, then the basic equations are described and related to the Langmuir and Freundlich isotherms. Applications to education are covered.

An approach developed for teaching descriptive inorganic chemistry courses involves presenting a limited set of facts about several elements or several compounds. The facts are not memorized, but used as jumping-off points for inquiry into whys and wherefores of the chemistry of the elements. Stoichiometries of known, stable binary compounds is a fundamental aspect of descriptive chemistry, but it is not interesting to memorize a list of chemical formulas when d-metals compound stochiometry is studied.

Stoichiometry is a difficult subject to teach secondary school students but it is essential for understanding qualitative and quantitative chemical reactions. It is therefore essential that teachers design and use appropriate strategies to address these difficulties and to help students become conceptual problem solvers. A new study of students' problem solving strategies classifies them into three categories: correct, incorrect and incomplete strategies. Details of the study are further presented.

A humorous approach to teaching stoichiometry and moles minimizes information overload and allows chemistry students to develop a better understanding of the mole concept. The approach uses a locational device called Moe's Mall that is based on dimensional analysis. Moe's Mall provides a single algorithm for solving all mole-based exercises and so students do not have to memorize discrete solutions to each exercise. Guidelines for implementing Moe's Mall in chemistry classes are included.

The graphic organizer method aims to help students, especially beginners, by simplifying stoichiometry problems involving abstract equations and symbols. The graphic organizer enables students to grasp the relationship between reactants and products in a clear manner with the use of simple diagrams. The stoichiometry graphic organizer does not interfere with normal studies and the students can abandon it once they have mastered the stoichiometric concepts.

Chemical reactions are more effectively taught using atomic or molecular models. An innovative approach of teaching uses several sets of circular magnets and a tin pizza pan. The magnets can represent the interacting particles and the interaction itself can be illustrated on the pie plate. This exercise will help students solve problems in stoichiometry.

A experiment in which the empirical formula of a simple binary compound is determined has been developed for beginning stoichiometry study in general chemistry courses. The empirical formula of a copper oxide salt is found using two methods, a methane reaction and an aluminum reaction. Students pool their data in each method. With two sets of data they cut down the error in the final calculations. They are involved in interactions with one another as they solve the problem. The proportion of copper in the unknown copper oxide can be seen to be independent of the method used to isolate the pure metal.

A experiment designed to measure the stoichiometry of copper oxide is described. Specified quantities of copper oxide and charcoal are placed into a glass tube with an attached long narrow glass tube with a water band inserted. Water is added and then heated and the production of carbon dioxide raises the water band.

A pictorial representation of the ways by which chemists specify an amount of a material is given and recommended for use by teachers and students of chemistry. A systematic way of creating a visual representation or map for the solution of typical stoichiometry problems discussed in general chemistry is then given and suggested as useful in making calculations. All stoichiometry problems become variations on one theme. Topics include gram-to-gram, mole-to-mole, and limiting reagent problems and extensions to amount of gas expressed by volume at STP and extension to problems that involve a solution or a titration.

Incomplete combustion demonstrations for the teaching of chemistry are discussed. Kinetics may be more important than thermodynamics of stoichiometry in explaining what takes place in the real world. An experiment with favorable kinetics has been developed to actually reach equilibrium. It is shown that experiments that purport to measure the percent oxygen in air stoichiometrically by burning candles or other means of that sort must fail because the rate goes to zero while the reaction is spontaneous. Favorable kinetics must exist in the experiment to reach equilibrium. A new and better demonstration has been developed.

The concept of extent of reaction can be used in introductory chemistry courses to help students learn. The approach to stoichiometry and limiting reagent calculations suggested uses the physical significance of the extent of reaction as a measure of the number of times the change that is equivalent to the balanced equation has taken place. The coefficient of a reagent would then be the change in amount every time the change takes place. The symbols make a much-needed distinction between changes in amounts and starting amounts.

Amounts tables can be used as a diagnostic tool for faulty stoichiometric reasoning on the part of chemistry students based on results of a pilot study involving second-semester students in a general chemistry class. Students were given a simple limiting reagent problem. About a third of the students did not take stoichiometric coefficients into account. Incorrect application of an algorithm for determining the limiting reagent was a common mistake. Some used seriously deficient reasoning and made errors that were interesting for their idiosyncrasies. About half of the students had a satisfactory grasp of stoichiometric reasoning.

The stoichiometry of the neutralization of citric acid by sodium hydroxide is determined in the chemistry laboratory using the continuous variation method. The method encourages teamwork and active learning. The concept of acid-base neutralization and the evolution of heat is briefly discussed. The class is divided into groups which use a different ratio of acid and base for the experiment. The results of each group are plotted, which confirm the 3:1 stoichiometry of the reaction. A discussion on the stoichiometry and the other related topics is conducted at the end of the laboratory session.

Calculating for carbon footprints begins with the balanced chemical equation for the reaction that produces the carbon dioxide gas. The footprint of each source can be determined from its carbon dioxide emission factor. Stoichiometry, thermochemistry, and the ideal gas law is useful in this student activity.

The decomposition of hydrogen peroxide and the formation of oxygen gas can be demonstrated using a short, safe and simple experiment. The procedure involves adding a small amount of yeast to hydrogen peroxide contained in a volumetric flask. The oxygen gas yielded in this reaction is allowed to pass through a rubber tubing and ends up in a graduated cylinder. The escape of oxygen from the solution can be shown by weighing the reactants and by performing the 'glowing splint' test. This activity can be adapted for use in the preparation of oxygen gas in the laboratory.

Stoichiometry, enthalpies of reactions and solutions, and heat transfer are tackled in a science activity that uses two commercial self-heating food products. Students get to calculate the heat produced by the chemical reaction or the dissolution process in this activity.

A demonstration of the titration of HCl with NaOH with phenolphthalein indicator is conducted to explain the concepts of acid-base chemistry and stoichiometry to the students. The phenolphthalein-pink tornado demonstration also helps the applications of the limiting reagent to the observer.

A food motivation activity, using a candy bar for high school chemistry classes is described. The use of everyday item like candy makes lab session interesting for students and may also help connect chemical concepts to their observable world and encourage them to ask questions.

A method was developed to give more quantitative data on reaction stoichiometry and provide more insight into the combustion processes. The method would make excellent classroom demonstration or investigation because they provide ample opportunity for students to make predictions about the range when the fuel to oxygen ratio is varied for variety of fuels.

A study was conducted to assess junior and high school students learning achievement in the topic of stoichiometry by using The Student Conceptual Understanding Test (SCUT). The low student achievement on the SCUT test deserves special attention from chemistry teachers, and it is stated that effective teaching strategies to promote student understanding should be developed.

A work that illustrates the power of a stoichiometric approach to evolution across multiple scales is reviewed, and then points to important open questions that may chart the way forward in the field of ecological stoichiometry. At the molecular level, stoichiometry links hereditary changes in the molecular composition of organisms to key phenotypic functions.

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 that a simple titration method with optical detection assists in determining the complex ion stoichometry.

The calculations of uncertainties in the formula or molar masses of compounds are streamlined. Three rules of increasing complexity are proposed, which overestimate the uncertainty so there is little if any risk that the true values are missed.

The existence of different stoichiometries in two basic zinc carbonates helps to explain their decomposition potential, and to select between the two compound formulas, which better describes zinc carbonate. The accuracy of the experiment makes it a viable means for students to perform various quantitative measurements.

The study of stoichiometry deals with the skills of balancing equations and the usage of these equations to calculate the masses involved in chemical reactions. This includes some mathematical operations on the chemical reactions, to find out the final product.

A study called Multidimensional Analysis System (MAS) for quantitative chemistry problems is conducted to analyze the introductory stoichiometry problems. The MAS is tested with two groups of students, and the result revealed that the achievements of both groups increased according to the usage of this system.

Two experiments concerning the synthesis of zinc iodide from its elements, which involve an alternate synthesis as well as an investigation of the side reaction, are discussed. The results suggest that these experiments could help introductory chemistry students understand some fundamental concepts related to stoichiometry.

A procedure that makes it pos sible for students to focus on the central issues of s toichiometry, not data collection, which is automated, in introductory and general chemistry labs has been developed and uses the reaction of magnesium with hydrochloric acid. At least five trials can be done in a 3 -hour lab period. A graph of th e amount in moles of hydrogen produced vs the amount of magnesium used in the reaction can help students see the linear relationship between products and reactants .

Students of chemistry can learn about stoichiometry by carrying out a n undergraduate general chemistry experiment involving determination of percent by mass of sodium bicarbonate, NaHCO(sub.3), in Alka Seltzer, an over-the-counter pain reliever and antacid . Using a simple method, students measure the weight loss and use a common household material, vinegar. High school or college general chemistry students can learn from carrying out this exercise. The use of familiar materials makes the activity more interesting.

An analogy is drawn between understanding of a problem and the solution with the help of a mental map with clear directions towards a solution, and a city's clearly laid out map, which is called the Mole city. It is argued that a student is more likely to think when the logical steps are clearly laid out, as, for example, paths on a map.

Understanding of stoichiometry for those first learning it can be much enhanced by resenting the concepts in a concrete manner, using familiar objects such as Lego, or a similar product, building-block car kits. Car kits are chosen because usually at least one piece, the tire piece, is used at least four times and at least one piece, the steering wheel, is used only once.

A classroom activity using fizzy drinks has been developed for use as a stoichiometry introduction in a general or advanced high school course or an introductory college one. It can be a concluding activity for testing on stoichiometry fundamentals. Fizzies drink tablets may be demonstrated to introduce the activity, in which students create their own carbonated beverage, learning that too much baking soda or too much citric acid will ruin flavor. Both aspartame and sugar are used.

Chemical concepts can be applied to a scenario to teach students, who may be non-chemistry majors or in upper-level analytical or environmental chemistry courses, about some principles of moles and molar masses and elementary stoichiometry or about advanced concepts. The effectiveness of two deicers, rock salt and calcium magnesium acetate, must be evaluated based on a written scenario in which a town council must decide how to budget for deicing of a new bridge giving direct, easy access to a large city nearby.

Students of chemistry can learn from a new, safe demonstration that uses apparatus similar to the traditional ammonia fountain equipment. It uses hydrogen chloride gas in the place where water was used in the traditional demonstration. Water is placed in the flask; the pressure decreases as in the ammonia fountain. Hydrogen chloride is drawn into the flask instead of water, and ammonia combines with hydrogen chloride to form ammonium chloride smoke, which is produced in puffs. The new demonstration is easy, interesting and can be a way to show several important properties and concepts, among them high solubility of ammonia in water, basicity of ammonia, acidity of HCl and the solid state of ionic compounds. Concepts learned may include stoichiometry, heat capacity, gas laws and thermochemistry.

Chemistry students at the secondary level can learn about matter and its behavior at the particle level by making flip books with about twenty 3 x 5 cards. The books allow an illusion of motion and are best used for a rather simple reaction. The students need to be sure to use a color code or labeling system to make representations of atoms identifiable.

The titration of carbon dioxide-containing, commercially available mixtures can be used to teach acid-base reaction principles and stoichiometry in the general, quantitative analysis and physical chemistry course. The experiment requires readily available, low-cost equipment and interests students through its real-world samples, such as soda, and the use of rubber balloons.

Usage of real objects in teaching solutions to stoichiometric problems is a useful strategy in proving students with a strong conceptual knowledge base of stoichiometry. Such innovations in chemistry teaching can ensure that students gain much-needed insight on chemical formulas.

Chemistry teachers can use rockets made of plastic Beral pipets to teach students about chemical stoichiometry. The pipets are ignited after being filled with hydrogen and oxygen. The pipets having the proper ratio of hydrogen to oxygen travel the farthest. Glass vials or test tubes can be made into highly efficient micro-Kipp gas generators. Water is poured into the rockets, which are placed over the exit tube of the generator.

Chemical concepts applied to bizarre or sensational situations intrigue students and one such experiment determines the concentration of HCN produced in a fire when polyacrylonitrile is burned. HCN is used in gas chambers but is also a by-product of burning polyacrylonitrile so students can calculate how much carpet or other polyacrylonitrile-containing products must burn before a lethal dose of HCN is produced.