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Journal Articles: 26 results
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
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
Using the Science Writing Heuristic To Improve Students' Understanding of General Equilibrium  James A. Rudd, II, Thomas J. Greenbowe, and Brian M. Hand
This study examines the performance of students using the Science Writing Heuristic approach, which facilitates scientific inquiry by structuring the laboratory notebook in a format that guides students to answer directed questions, on lecture exams and a laboratory practical exam on chemical equilibrium.
Rudd, James A., II; Greenbowe, Thomas J.; Hand, Brian M. J. Chem. Educ. 2007, 84, 2007.
Equilibrium |
Learning Theories |
TA Training / Orientation |
Student-Centered Learning
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
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
Equilibria That Shift Left upon Addition of More Reactant  Jeffrey E. Lacy
Most textbook presentations of Le Chtelier'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
Playing-Card Equilibrium  Robert M. Hanson
A simple hands-on simulation suitable for either classroom use or laboratory investigation involves using a standard deck of playing cards to explore the statistical aspects of equilibrium. Concepts that can be easily demonstrated include fluctuation around a most probable distribution, Le Chtelier's principle, the equilibrium constant, prediction of the equilibrium constant based on probability, and the effect of sample size on equilibrium fluctuations.
Hanson, Robert M. J. Chem. Educ. 2003, 80, 1271.
Equilibrium |
Statistical Mechanics |
Thermodynamics
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
Simulating Dynamic Equilibria: A Class Experiment  John A. Harrison and Paul D. Buckley
A first-order reversible reaction is simulated on an overhead projector using small coins or discs. Results illustrate how dynamic equilibria are established and allow the introduction of the concept of an equilibrium constant. Le Chtelier's principle is illustrated by further simulations.
Harrison, John A.; Buckley, Paul D. J. Chem. Educ. 2000, 77, 1013.
Equilibrium |
Rate Law |
Reactions
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
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
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
Tools of the trade   Bruno, Michael J.
High school teachers can never have too many visual aids when teaching chemistry. This author shares some demonstrations in equilibrium that often produce "oohs" and "aaaahs" from his students.
Bruno, Michael J. J. Chem. Educ. 1988, 65, 698.
Equilibrium |
pH
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
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
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
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
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
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
An apparent contradiction in the application of the principle of Le Chtelier  Mellon, E. K.
Unless some care is exercised, the application of free energy concepts in situations where marked temperature changes occur can lead to apparent contradictions like the one described in this paper.
Mellon, E. K. J. Chem. Educ. 1979, 56, 380.
Equilibrium |
Thermodynamics
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
A dynamic lecture demonstration of dynamic equilibrium - The BG system  Battino, Rubin
This demonstration uses students as atoms and molecules.
Battino, Rubin J. Chem. Educ. 1975, 52, 55.
Equilibrium
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
The design and use of an equilibrium machine  Alden, Robert T.; Schmuckler, Joseph S.
An operating model that can be used to determine quantitatively equilibrium shifts when demonstrating Le Chatelier's Principle and relates to molecular level considerations and the probabilistic nature of equilibrium.
Alden, Robert T.; Schmuckler, Joseph S. J. Chem. Educ. 1972, 49, 509.
Equilibrium
Principles of chemical equilibrium (Morris, Kelso B.)  Eblin, Lawrence P.

Eblin, Lawrence P. J. Chem. Educ. 1966, 43, 110.
Equilibrium |
Enrichment / Review Materials
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