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Journal Articles: 47 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
The Physical Meaning of the Mathematical Formalism Present in Limiting Chemical Equations; Or, How Dilute Is Dilute?  C. Contreras-Ortega, N. Bustamante, J. L. Guevara, C. Portillo, and V. Kesternich
Proposes general mathematical formulations to offer students a better understanding of the real scope of scientific expressions dealing with limiting physical conditions, such as those concerning dilute and concentrated solutions and low and high temperatures and pressures.
Contreras-Ortega, C.; Bustamante, N.; Guevara, J. L.; Portillo, C.; Kesternich, V. J. Chem. Educ. 2007, 84, 788.
Aqueous Solution Chemistry |
Equilibrium |
Gases |
Mathematics / Symbolic Mathematics |
Quantitative Analysis |
Solutions / Solvents
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
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
The Reaction Quotient Is Unnecessary To Solve Equilibrium Problems  Paul S. Matsumoto
The traditional method to determine the equilibrium concentration of chemicals in a reaction, given the equilibrium constant and the initial concentration of chemicals in the reaction, involves the determination of the reaction quotient. This article will demonstrate that this step may be eliminated; thereby simplifying the algorithm to solve such problems. Such a reduction in the complexity of the algorithm may result in more students successfully being able to solve such problems.
Matsumoto, Paul S. J. Chem. Educ. 2005, 82, 406.
Equilibrium |
Learning Theories |
Chemometrics
Unified Approximations: A New Approach for Monoprotic Weak Acid–Base Equilibria  Harry L. Pardue, Ihab N. Odeh, and Teweldemedhin M. Tesfai
This article describes a new approach to approximate calculations for monoprotic acidbase equilibria in otherwise pure water. The new approach, identified herein as unified approximations, uses a simple decision criterion to select between situations that should be treated as deprotonation and protonation reactions. The remaining treatment takes account of changes in concentrations of conjugate acidbase pairs for all situations and ignores autoprotolysis only for situations for which the analytical concentration of either the conjugate acid or conjugate base will always be larger than zero.
Pardue, Harry L.; Odeh, Ihab N.; Tesfai, Teweldemedhin M. J. Chem. Educ. 2004, 81, 1367.
Acids / Bases |
Equilibrium |
Chemometrics
Equilibrium  Matthew Sandberg and Michael K. Bellamy
Software (applet) to help students visualize what actually happens in an equilibrium system.
Sandberg, Matthew ; Bellamy, Michael K. J. Chem. Educ. 2003, 80, 456.
Equilibrium |
Molecular Modeling |
Molecular Mechanics / Dynamics
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
Equilibrium: A Teaching/Learning Activity: Author Reply  Audrey Wilson
Thanks for input.
Wilson, Audrey . J. Chem. Educ. 2000, 77, 1410.
Equilibrium
Equilibrium: A Teaching/Learning Activity  Todd P. Silverstein
Further refinement of equilibrium activity.
Silverstein, Todd P. J. Chem. Educ. 2000, 77, 1410.
Equilibrium
Graphing Calculator Strategies for Solving Chemical Equilibrium Problems  Henry Donato Jr.
A general method for finding the roots of polynomial equations using the ubiquitous and inexpensive graphing calculator is presented. It is suggested that important reactions, which are not discussed in introductory chemistry courses because of computational considerations, may now be discussed.
Donato, Henry, Jr. J. Chem. Educ. 1999, 76, 632.
Aqueous Solution Chemistry |
Learning Theories |
Equilibrium
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
A Simplified Method for Finding the pKa of an Acid-Base Indicator by Spectrophotometry  George S. Patterson
Experiments on determining the pKa of an acid-base indicator by visible spectroscopy are often found in analytical and physical chemistry lab texts. The procedure described here is a modification suitable for general chemistry lab students.
Patterson, George S. J. Chem. Educ. 1999, 76, 395.
Acids / Bases |
Equilibrium |
UV-Vis Spectroscopy
The Fizz Keeper, a Case Study in Chemical Education, Equilibrium, and Kinetics  Reed Howald
The chemistry of the loss of carbonation from carbonated beverages on storage is considered. Increasing the pressure of CO2(g) will restore carbonation, but an increase in pressure adding air should not affect the equilibria. It can and does, however, affect the kinetics-the rate at which a new equilibrium is established. Thus the Fizz Keeper is effective for storage of resealed pop containers for hours, but not for periods of weeks or months.
Howald, Reed. J. Chem. Educ. 1999, 76, 208.
Transport Properties |
Equilibrium |
Gases |
Kinetics |
Aqueous Solution Chemistry |
Consumer Chemistry |
Applications of Chemistry
Why and How To Teach Acid-Base Reactions without Equilibrium  Terry S. Carlton
A stepwise method enables students to predict which acid-base reactions occur when two solutions are mixed. The complexities of equilibrium are avoided by treating reactions as all-or-none and by providing a table of acids in order of strength.
Carlton, Terry S. J. Chem. Educ. 1997, 74, 939.
Learning Theories |
Acids / Bases |
Aqueous Solution Chemistry |
Equilibrium
Thermodynamics and Spontaneity  Raymond S. Ochs
Despite the importance of thermodynamics as the foundation of chemistry, most students emerge from introductory courses with only a dim understanding of this subject.
Ochs, Raymond S. J. Chem. Educ. 1996, 73, 952.
Thermodynamics |
Learning Theories |
Equilibrium
Chemical Equilibrium in the General Chemistry Course  Fainzilberg, Vladimir E.; Karp, Stewart
The first chapters on chemical equilibrium in first-year college chemistry texts make an "error" in the solution of certain types of equilibria problems.
Fainzilberg, Vladimir E.; Karp, Stewart J. Chem. Educ. 1994, 71, 769.
Equilibrium |
Kinetics
The acid equilibrium constant is unity!  Baldwin, W. G.; Burchill, C. E.
The attempt to assign a non-unity value to this equilibrium constant is a consequence of misunderstanding the way in which the (nearly) constant concentration or activity of the solvent in a dilute solution (or of a pure solid or liquid in a heterogeneous system) is treated when formulating the conventional equilibrium constant expression.
Baldwin, W. G.; Burchill, C. E. J. Chem. Educ. 1992, 69, 514.
Acids / Bases |
Equilibrium |
Aqueous Solution Chemistry
Advanced titration plots using spreadsheet scripting  Currie, James O., Jr.; Whiteley, Richard V., Jr.
131. A spreadsheet aids in student understanding of acid/base titration calculations.
Currie, James O., Jr.; Whiteley, Richard V., Jr. J. Chem. Educ. 1991, 68, 923.
Acids / Bases |
Titration / Volumetric Analysis |
pH |
Laboratory Computing / Interfacing |
Equilibrium
Chemical equilibrium: III. A few math tricks   Gordus, Adon A.
The third article in a series on chemical equilibrium that considers a few math "tricks" useful in equilibrium calculations and approximations.
Gordus, Adon A. J. Chem. Educ. 1991, 68, 291.
Acids / Bases |
Equilibrium |
Chemometrics |
Titration / Volumetric Analysis
Chemical equilibrium: II. Deriving an exact equilibrium equation   Gordus, Adon A.
In this article appearing in a series on chemical equilibrium, authors consider how to derive a completely general equation for any chemical mixture.
Gordus, Adon A. J. Chem. Educ. 1991, 68, 215.
Equilibrium |
Chemometrics
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
Measurements of equilibrium constants of acid-base indicators with a blocktronic colorimeter  Walters, David; Birk, James P.
A computer-interfaced measurement of equilibrium constants of acid-base indicators (methyl orange, methyl red, and phenolphthalein).
Walters, David; Birk, James P. J. Chem. Educ. 1990, 67, A252.
Acids / Bases |
Dyes / Pigments |
Spectroscopy |
Equilibrium |
Laboratory Computing / Interfacing
Solving quadratic equations  Brown, R. J. C.
A better technique than the quadratic equation for chemical equilibria is offered here.
Brown, R. J. C. J. Chem. Educ. 1990, 67, 409.
Chemometrics |
Equilibrium
An efficient method for the treatment of weak acid/base equilibria  Burness, James H.
The use of the ionization ratio concept enables students to perform many of the calculations for aqueous acid/base equilibria more quickly and efficiently.
Burness, James H. J. Chem. Educ. 1990, 67, 224.
Equilibrium |
Acids / Bases
The extent of acid-base reactions  Thompson, Ralph J.
How to calculate the equilibrium constant of an acid-base reaction.
Thompson, Ralph J. J. Chem. Educ. 1990, 67, 220.
Acids / Bases |
Reactions |
Equilibrium
Solving equilibrium constant expressions using spreadsheets  Metz, Clyde; Donato, Henry, Jr.
Description and application of solving equilibrium constant expressions using spreadsheets.
Metz, Clyde; Donato, Henry, Jr. J. Chem. Educ. 1989, 66, A241.
Equilibrium
Computer simulation of chemical equilibrium  Cullen, John F., Jr.
108. The "Great Chemical Bead Game" requires no instruments and presents the concepts of equilibrium and kinetics more clearly than an experiment. [October and November Computer Series both inadvertently called number 107. Numbering restored by skipping 109 and calling January 1990 number 110.]
Cullen, John F., Jr. J. Chem. Educ. 1989, 66, 1023.
Equilibrium |
Kinetics |
Rate Law
Solution equilibrium problems(Moss, David B.)  Cass, Don; Murray, Marilee
Two reviews of a two disk set with a 44-page manual that discusses equilibria in general and specific techniques of solving equilibrium problems.
Cass, Don; Murray, Marilee J. Chem. Educ. 1988, 65, A114.
Equilibrium
Correct equilibrium constants for water  Baldwin, W. George; Burchill, C. Eugene
Disagreement with the numerical values assigned to equilibrium constants.
Baldwin, W. George; Burchill, C. Eugene J. Chem. Educ. 1987, 64, 1067.
Equilibrium |
Water / Water Chemistry |
Acids / Bases |
Aqueous Solution Chemistry
Solubility and Ksp of calcium sulfate: a general chemistry laboratory experiment  Sawyer, Albert K.
The experiment shared in this note can be used to accompany lectures on solubility or chemical equilibrium.
Sawyer, Albert K. J. Chem. Educ. 1983, 60, 416.
Solutions / Solvents |
Aqueous Solution Chemistry |
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
Intuitive and general approach to acid-base equilibrium calculations  Felty, Wayne L.
The purpose of this paper is to show that the usual intuitive approach used in general chemistry can be readily extended without introduction of additional, sophisticated concepts to give the general, exact expression and to point out the pedagogical advantage of its use.
Felty, Wayne L. J. Chem. Educ. 1978, 55, 576.
Acids / Bases |
Equilibrium |
Chemometrics
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 computer program to support equilibrium constant theory  Thielmann, Vernon
A Fortran IV program calculates ten different K values based on different equilibrium expressions that are chosen at random.
Thielmann, Vernon J. Chem. Educ. 1975, 52, 468.
Equilibrium
Molar solubility calculations and the control equilibrium  Chaston, S. H. H.
The Control-Equilibrium method uses as its starting point a precise procedure for obtaining the equilibrium that accounts for the bulk of the decomposition of starting materials.
Chaston, S. H. H. J. Chem. Educ. 1975, 52, 206.
Solutions / Solvents |
Chemometrics |
Equilibrium
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
Demonstrating the relation between rate constants and the equilibrium constant  Meyer, Edwin F.; Glass, Edward
Presents an approach used with an apparatus to demonstrate quantitatively the relationship between rate constants and the equilibrium constant for simple reversible reactions.
Meyer, Edwin F.; Glass, Edward J. Chem. Educ. 1970, 47, 646.
Rate Law |
Equilibrium |
Reactions
Component concentrations in solutions of weak acids  Goldish, Dorothy M.
presents a new approach to teaching the subject of weak acid equilibria and its associated calculations.
Goldish, Dorothy M. J. Chem. Educ. 1970, 47, 65.
Acids / Bases |
Aqueous Solution Chemistry |
Equilibrium |
Chemometrics |
pH
Rapid graphical method for determining formation constants  Christian, Sherril D.
This paper presents a rapid graphical method for determining formation constants and absorptivities of 1:1 complexes in dilute solution.
Christian, Sherril D. J. Chem. Educ. 1968, 45, 713.
Equilibrium
Principles of chemical equilibrium (Morris, Kelso B.)  Eblin, Lawrence P.

Eblin, Lawrence P. J. Chem. Educ. 1966, 43, 110.
Equilibrium |
Enrichment / Review Materials
KineticsEarly and often  Campbell, J. A.
Describes an approach to investigating kinetics and its application to the "blue bottle" experiment.
Campbell, J. A. J. Chem. Educ. 1963, 40, 578.
Kinetics |
Equilibrium |
Mechanisms of Reactions
Heterogeneous equilibria in general chemistry  Grotz, Leonard C.
Presents suggestions for approaching the subject of heterogeneous equilibria in general chemistry.
Grotz, Leonard C. J. Chem. Educ. 1963, 40, 479.
Equilibrium |
Kinetics
Temperature dependence of equilibrium: A first experiment in general chemistry  Mahan, Bruce H.
This experiment uses cooling curves to derive the expression for the temperature dependence of the equilibrium constant.
Mahan, Bruce H. J. Chem. Educ. 1963, 40, 293.
Equilibrium |
Thermodynamics
Potentiometric measurements of equilibria: In general chemistry laboratory  Chesick, J. P.; Patterson, Andrew, Jr.
The authors describe an experiment in which the solubility product of silver chloride, the ionization constant of the silver-ammonia complex, and the ionization constant of acetic acid can be determined with one afternoon of work.
Chesick, J. P.; Patterson, Andrew, Jr. J. Chem. Educ. 1959, 36, 496.
Electrochemistry |
Equilibrium |
Precipitation / Solubility |
Aqueous Solution Chemistry |
Acids / Bases
Praseodymium tetrafluoride  Perros, Theodore P.; Munson, Thomas R.; Naeser, Charles R.
In spite of the experimental failures to prepare praseodymium tetrafluoride, there is strong evidence for its possible formation to be found by calculating the equilibrium constants for some of the reactions by which this compound might be prepared.
Perros, Theodore P.; Munson, Thomas R.; Naeser, Charles R. J. Chem. Educ. 1953, 30, 402.
Oxidation State |
Equilibrium |
Thermodynamics
A procedure for solving equilibrium problems  Boyd, Robert Neilson
A procedure for solving equilibrium problems is illustrated through several sample problems.
Boyd, Robert Neilson J. Chem. Educ. 1952, 29, 198.
Equilibrium |
Chemometrics |
Aqueous Solution Chemistry