| Journal Articles: 42 results |
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Does the Addition of Inert Gases at Constant Volume and Temperature Affect Chemical Equilibrium? João C. M. Paiva, Jorge Gonçalves, and Susana Fonseca
This article examines three approaches, leading to different conclusions, for answering the question "Does the addition of inert gases at constant volume and temperature modify the state of equilibrium?"
Paiva, João C. M.; Gonçalves, Jorge; Fonseca, Susana. J. Chem. Educ. 2008, 85, 1133.
Equilibrium |
Gases |
Thermodynamics
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An Updated Equilibrium Machine Emeric Schultz
Describes a device that can demonstrate equilibrium and the Le Châtelier principle, as well as kinetic and thermodynamic concepts. The device consists of a leaf blower attached to a plastic container divided into two chambers by a barrier of variable size and form. Styrofoam balls can be exchanged across the barrier when various air pressures are applied by the blower.
Schultz, Emeric. J. Chem. Educ. 2008, 85, 1131.
Equilibrium |
Kinetics |
Thermodynamics
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A Simplified Model To Predict the Effect of Increasing Atmospheric CO2 on Carbonate Chemistry in the Ocean Brian J. Bozlee, Maria Janebo, and Ginger Jahn
The chemistry of dissolved inorganic carbon in seawater is reviewed and used to predict the potential effect of rising levels of carbon dioxide in the atmosphere. It is found that calcium carbonate may become unsaturated in cold surface seawater by the year 2100, resulting in the destruction of calcifying organisms such as coral.
Bozlee, Brian J.; Janebo, Maria; Jahn, Ginger. J. Chem. Educ. 2008, 85, 213.
Applications of Chemistry |
Aqueous Solution Chemistry |
Atmospheric Chemistry |
Equilibrium |
Green Chemistry |
Water / Water Chemistry
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Exception to the Le Châtelier Principle David S. Corti and Mark J. Uline
Disagreement regarding an apparent exception to the Le Chtelier principle involving the effects of nonideality on the direction in which the ammonia synthesis reaction shifts upon addition of infinitesimal and finite quantities of nitrogen at constant pressure and temperature.
Corti, David S.; Uline, Mark J. J. Chem. Educ. 2007, 84, 1427.
Equilibrium
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Exception to the Le Châtelier Principle Thomas R. Herrinton
Disagreement regarding an apparent exception to the Le Chtelier principle involving the effects of nonideality on the direction in which the ammonia synthesis reaction shifts upon addition of infinitesimal and finite quantities of nitrogen at constant pressure and temperature.
Herrinton, Thomas R. J. Chem. Educ. 2007, 84, 1427.
Equilibrium |
Gases
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Exception to the Le Châtelier Principle Thomas R. Herrinton
Disagreement regarding an apparent exception to the Le Chatelier principle involving the effects of nonideality on the direction in which the ammonia synthesis reaction shifts upon addition of infinitesimal and finite quantities of nitrogen at constant pressure and temperature.
Herrinton, Thomas R. J. Chem. Educ. 2007, 84, 1427.
Equilibrium |
Gases
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Achieving Chemical Equilibrium: The Role of Imposed Conditions in the Ammonia Formation Reaction Joel Tellinghuisen
The conditions under which chemical reactions occur determine which thermodynamic functions are minimized or maximized. This point is illustrated for the formation of ammonia in the ideal gas approximation using a numerical exercise.
Tellinghuisen, Joel. J. Chem. Educ. 2006, 83, 1090.
Gases |
Equilibrium |
Thermodynamics
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Give Them Money: The Boltzmann Game, a Classroom or Laboratory Activity Modeling Entropy Changes and the Distribution of Energy in Chemical Systems Robert M. Hanson and Bridget Michalek
Described here is a short, simple activity that can be used in any high school or college chemistry classroom or lab to explore the way energy is distributed in real chemical systems and as an entry into discussions of the probabilistic nature of entropy.
Hanson, Robert M.; Michalek, Bridget. J. Chem. Educ. 2006, 83, 581.
Equilibrium |
Statistical Mechanics |
Thermodynamics
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Equilibria That Shift Left upon Addition of More Reactant Jeffrey E. Lacy
Most textbook presentations of Le Chtelier's principle in general and physical chemistry do not include a discussion of constant pressure conditions for which addition of a reactant can shift the equilibrium to the left. We propose presentations of isothermal, open systems at constant pressure for both levels of study by using concepts and skills that the respective students already possess. In addition, we derive novel criteria based on the stoichiometry of the reaction that can be used to identify those equilibria that will shift left upon addition of more reactant.
Lacy, Jeffrey E. J. Chem. Educ. 2005, 82, 1192.
Equilibrium |
Mathematics / Symbolic Mathematics |
Thermodynamics
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Microscopic Description of Le Châtelier's Principle Igor Novak
The analysis based on microscopic descriptors (energy levels and their populations) is given that provides visualization of free energies and conceptual rationalization of Le Châtelier's principle. The misconception "nature favors equilibrium" is highlighted.
Novak, Igor. J. Chem. Educ. 2005, 82, 1190.
Equilibrium |
Thermodynamics
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The Reaction Quotient Is Unnecessary To Solve Equilibrium Problems Paul S. Matsumoto
While my paper states that the reaction quotient (Q) is not needed to solve equilibrium problems, it does not imply that Q is not valuable. In fact, when I teach this topic to my AP chemistry class, I initially use Q to solve the problem, then mention the alternative method described in the paper.
Matsumoto, Paul S. J. Chem. Educ. 2005, 82, 1150.
Equilibrium |
Learning Theories |
Mathematics / Symbolic Mathematics
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The Reaction Quotient Is Unnecessary To Solve Equilibrium Problems: No Problems with Q Robert Lederer
Mr. Matsumotos students are to be congratulated for discerning an interesting mathematical procedure. Exclusively utilizing this algorithm, however, short-cuts the understanding of the chemistry involved. Students of chemistry should be challenged to understand why something occurs, and not to be satisfied with how to perform the often mundane calculations.
Lederer, Robert. J. Chem. Educ. 2005, 82, 1149.
Equilibrium |
Mathematics / Symbolic Mathematics
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The Reaction Quotient Is Unnecessary To Solve Equilibrium Problems: The Reaction Quotient (Q) IS Useful After All Todd P. Silverstein
Paul Matsumoto was absolutely correct in writing The Reaction Quotient Is Unnecessary To Solve Equilibrium Problems.
Silverstein, Todd P. J. Chem. Educ. 2005, 82, 1149.
Equilibrium |
Thermodynamics
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The Reaction Quotient Is Unnecessary To Solve Equilibrium Problems: The Reaction Quotient (Q) IS Useful After All Todd P. Silverstein
Paul Matsumoto was absolutely correct in writing The Reaction Quotient Is Unnecessary To Solve Equilibrium Problems.
Silverstein, Todd P. J. Chem. Educ. 2005, 82, 1149.
Equilibrium |
Thermodynamics
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Putting A Human Face on Equilibrium Neil Glickstein
A short biography of chemist Fritz Haber is used to personalize the abstract concepts of equilibrium chemistry for high school students in an introductory course. In addition to giving the HaberBosch process an historic, an economic, and a scientific background the reading and subsequent discussion allows students for whom the human perspective is of paramount importance a chance to investigate the irony of balance or equilibrium in Haber's life story.
Glickstein, Neil. J. Chem. Educ. 2005, 82, 391.
Equilibrium
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Using Clinical Cases To Teach General Chemistry Brahmadeo Dewprashad, Charles Kosky, Geraldine S. Vaz, and Charlotte L. Martin
This article describes how a fact-based clinical case was effectively used to motivate and enrich the classroom experience and review many of the concepts covered in general chemistry. The case involves an elderly patient who was brought to the emergency room. The results of his physical examination and laboratory analysis of his blood are presented. The students, in peer-led groups, work through the chemical principles involved in the doctor's diagnosis and treatment options for the patient. The article describes the case study, instructors' observations, and students' perception of the activity.
Dewprashad, Brahmadeo; Kosky, Charles; Vaz, Geraldine S.; Martin, Charlotte L. J. Chem. Educ. 2004, 81, 1471.
Acids / Bases |
Drugs / Pharmaceuticals |
Equilibrium |
Kinetics |
Medicinal Chemistry
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Le Chat: Simulation in Chemical Equilibrium João C. M. Paiva, Victor M. S. Gil, and António Ferrer Correia
Software that illustrates Le Chatelier's principle; found on the Advanced Chemistry Collection CD-ROM, 3rd Edition.
Paiva, João C. M.; Gil, Victor M. S.; Correia, António Ferrer. J. Chem. Educ. 2003, 80, 111.
Equilibrium
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Rubber Bands, Free Energy, and Le Châtelier's Principle Warren Hirsch
Using a rubber band to illustrate Gibbs free energy, entropy, and enthalpy.
Hirsch, Warren. J. Chem. Educ. 2002, 79, 200A.
Noncovalent Interactions |
Thermodynamics |
Equilibrium
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The State of Division of Solids and Chemical Equilibria João C. M. Paiva and Victor M. S. Gil
An experiment and a computer simulation are presented to address a counterintuitive situation often encountered when teaching chemical equilibria. This is prompted by the question "How can the subdivision of a solid reactant affect the reaction rate and not the composition of the equilibrium state?"
Paiva, João C. M.; Gil, Victor M. S. J. Chem. Educ. 2001, 78, 222.
Equilibrium |
Kinetics |
Laboratory Computing / Interfacing
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Simulations for Teaching Chemical Equilibrium Penelope A. Huddle, Margaret Dawn White, and Fiona Rogers
This paper outlines a systematic approach to teaching chemical equilibrium using simulation experiments that address most known alternate conceptions in the topic. Graphs drawn using the data from the simulations are identical to those obtained using real experimental data for reactions that go to equilibrium. This allows easy mapping of the analogy to the target.
Huddle, Penelope Ann; White, Margaret Dawn; Rogers, Fiona. J. Chem. Educ. 2000, 77, 920.
Equilibrium |
Learning Theories
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The Complexity of Teaching and Learning Chemical Equilibrium Louise Tyson, David F. Treagust, and Robert B. Bucat
This paper discusses three key issues relevant to secondary school chemistry teaching. They arise from a study of students' understanding of chemical equilibrium using qualitative and quantitative research methods.
Tyson, Louise; Treagust, David F.; Bucat, Robert B. J. Chem. Educ. 1999, 76, 554.
Equilibrium |
Learning Theories
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Computers and Practical Chemistry Gipps, John
164. Particularly appropriate examples for the computer interfacing of laboratory experiments.
Gipps, John J. Chem. Educ. 1994, 71, 671.
Laboratory Computing / Interfacing |
Acids / Bases |
Equilibrium |
Reactions
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Chemical equilibrium: I. The thermodynamic equilibrium constant Gordus, Adon A.
This is the first article in a series of eight that investigates the various assumptions that result in the simplified equilibrium equations found in most introductory texts. In this first article, the author considers the general nature of the constant K, Le Chatelier's principle, and the effect of the temperature on K.
Gordus, Adon A. J. Chem. Educ. 1991, 68, 138.
Thermodynamics |
Equilibrium
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Student ideas regarding chemical equilibrium: What written test answers do not reveal Bergquist, Wilbur; Heikkinen, Henry
Examples, evidence, and implications of student misconceptions regarding chemical equilibrium.
Bergquist, Wilbur; Heikkinen, Henry J. Chem. Educ. 1990, 67, 1000.
Equilibrium |
Constructivism
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Teaching freezing point lowering Ball, Jenelle; Cooke, Ron C.; Willis, Grover
Using Le Chatelier's principle, the van't Hoff equation, and the empirical equation to explain the lowering of the freezing point caused by dissolving antifreeze in water.
Ball, Jenelle; Cooke, Ron C.; Willis, Grover J. Chem. Educ. 1990, 67, 676.
Physical Properties |
Solutions / Solvents |
Equilibrium |
Aqueous Solution Chemistry
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Experimental work with tin(II) chloride in a high school Sanchez, Manuela Martin
The author describes a final-project performed by students that integrates concepts of hydrolysis, Le Chatelier's principle, and electrolysis. Students seek answers to questions such as: "What reactions were involved; why is an aqueous solution of SnCl2 acidic; how can elemental tin be recovered from the system?"
Sanchez, Manuela Martin J. Chem. Educ. 1988, 65, 898.
Separation Science |
Electrochemistry |
Electrolytic / Galvanic Cells / Potentials |
Equilibrium |
Oxidation / Reduction
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Le Châtelier's Principle Knox, Kerro
Question involving effect of increasing the pressure on the N2 + 3H2 <=> 2NH3 system.
Knox, Kerro J. Chem. Educ. 1985, 62, 863.
Equilibrium |
Gases
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Le Châtelier's principle, temperature effects, and entropy Campbell, J. Arthur
A useful extension of Le Chatelier's Principle to predict concentration, pressure, and temperature effects solely from the equation for the net reaction.
Campbell, J. Arthur J. Chem. Educ. 1985, 62, 231.
Equilibrium |
Thermodynamics
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Cooking with chemistry Grosser, Arthur E.
Two demonstrations involving cooking eggs and suggestions for many more examples of cooking that illustrate important principles of chemistry. From the "State-of-the-Art Symposium for Chemical Educators: Chemistry of the Food Cycle".
Grosser, Arthur E. J. Chem. Educ. 1984, 61, 362.
Food Science |
Gases |
Acids / Bases |
Equilibrium |
Kinetics
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Le Châtelier's principle: the effect of temperature on the solubility of solids in liquids Brice, L. K.
The purpose of this article is to provide a rigorous but straightforward thermodynamic treatment of the temperature dependence of solubility of solids in liquids that is suitable for presentation at the undergraduate level. The present discussion may suggest how to approach the qualitative aspects of the subject for freshman.
Brice, L. K. J. Chem. Educ. 1983, 60, 387.
Thermodynamics |
Liquids |
Solids |
Chemometrics |
Equilibrium
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Chemical equilibrium Mickey, Charles D.
The law of mass action, the equilibrium constant, and the effect of temperature, concentration, and pressure on equilibrium.
Mickey, Charles D. J. Chem. Educ. 1980, 57, 801.
Equilibrium |
Catalysis
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Le Châtelier's principle: A reexamination and method of graphic illustration Treptow, Richard S.
Le Châtelier's development of the principle that bears his name, and a rephrasing of that principle to make it technically and historically accurate.
Treptow, Richard S. J. Chem. Educ. 1980, 57, 417.
Equilibrium
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A chemistry lesson at Three Mile Island Mammano, Nicholas J.
Teaching principles of general chemistry through references made to the nuclear incident at Three Mile Island.
Mammano, Nicholas J. J. Chem. Educ. 1980, 57, 286.
Equilibrium |
Gases |
Stoichiometry |
Nonmajor Courses |
Nuclear / Radiochemistry |
Applications of Chemistry
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On the misuse of Le Châtelier's principle for the prediction of the temperature dependence of the solubility of salts Bodner, George M.
Explores why Le Châtelier's principle often fails to predict the temperature dependence of the solubility of salts.
Bodner, George M. J. Chem. Educ. 1980, 57, 117.
Equilibrium |
Precipitation / Solubility |
Solutions / Solvents |
Aqueous Solution Chemistry
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The temperature dependence of the equilibrium constant Burness, James H.
This exam question tests a student's ability to derive the temperature dependence of an equilibrium constant not by qualitatively applying Le Chatelier's principle, but by understanding the relationship between the kinetics of the equation and the value of Keq.
Burness, James H. J. Chem. Educ. 1979, 56, 395.
Equilibrium |
Kinetics
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Le Chtelier's principle: A laboratory exercise Friedman, Frederica
Le Chtelier's principle can be demonstrated by showing that water can boil at temperatures below 100C due to reduced vapor pressure.
Friedman, Frederica J. Chem. Educ. 1977, 54, 236.
Equilibrium |
Phases / Phase Transitions / Diagrams |
Gases |
Water / Water Chemistry
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On mole fractions in equilibrium constants Delaney, C. M.; Nash, Leonard K.
Proposes a hybrid equilibrium constant for use in introductory chemistry courses.
Delaney, C. M.; Nash, Leonard K. J. Chem. Educ. 1977, 54, 151.
Equilibrium |
Stoichiometry |
Aqueous Solution Chemistry |
Solutions / Solvents
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Lecture experiment: A quantitative illustration of LeChatelier's principle Nelson, D. L.; Ginns, E. I.; Richtol, H. H.; Reeves, R. R.
A short experiment involving the popular gaseous nitrogen dioxide system has been developed into a lecture demonstration which quantitatively illustrates the behavior of a homogeneous gas-phase equilibrium under conditions of varying temperature and pressure.
Nelson, D. L.; Ginns, E. I.; Richtol, H. H.; Reeves, R. R. J. Chem. Educ. 1973, 50, 721.
Equilibrium |
Gases
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Gas Laws, Equilibrium, and the Commercial Synthesis of Nitric acid. A Simple Demonstration Alexander, M. Dale
This demonstration of the commercial production of nitric acid uses a simple apparatus to illustrate a number of basic chemical concepts, including Le Chatelier's principle.
Alexander, M. Dale J. Chem. Educ. 1971, 48, 838.
Synthesis |
Industrial Chemistry |
Acids / Bases |
Gases |
Equilibrium |
Reactions |
Stoichiometry
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Principles of chemical equilibrium (Morris, Kelso B.) Eblin, Lawrence P.
Eblin, Lawrence P. J. Chem. Educ. 1966, 43, 110.
Equilibrium |
Enrichment / Review Materials
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Concerning equilibrium, free energy changes, Le Châtelier's principle II Eberhardt, William H.
This demonstration involves a reversible, temperature-based transformation from blue tetrahedrally coordinated Co2+ to pink sixfold coordinated Co2+.
Eberhardt, William H. J. Chem. Educ. 1964, 41, A591.
Equilibrium |
Thermodynamics |
Aqueous Solution Chemistry |
Coordination Compounds
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Le Châtelier's principle and the equilibrium constant Miller, Arild J.
Many students of chemistry have difficulty in understanding how the position of equilibrium in a gaseous reaction can change when the pressure is altered, in accordance with Le Châtelier's principle, without causing a corresponding variation in the equilibrium constant.
Miller, Arild J. J. Chem. Educ. 1954, 31, 455.
Equilibrium |
Reactions |
Gases
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