| Journal Articles: 47 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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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
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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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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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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
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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 acidbase 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 acidbase 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
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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
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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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Equilibrium: A Teaching/Learning Activity: Author Reply Audrey Wilson
Thanks for input.
Wilson, Audrey . J. Chem. Educ. 2000, 77, 1410.
Equilibrium
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Equilibrium: A Teaching/Learning Activity Todd P. Silverstein
Further refinement of equilibrium activity.
Silverstein, Todd P. J. Chem. Educ. 2000, 77, 1410.
Equilibrium
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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
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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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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
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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
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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
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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
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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
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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
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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
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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
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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
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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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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
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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
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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
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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
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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
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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
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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
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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
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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
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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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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
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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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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
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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
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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
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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
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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
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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
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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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KineticsEarly 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
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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
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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
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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
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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
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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
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