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Journal Articles: 27 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
Introducing Undergraduate Students to Electrochemistry: A Two-Week Discovery Chemistry Experiment  Kenneth V. Mills, Richard S. Herrick, Louise W. Guilmette, Lisa P. Nestor, Heather Shafer, and Mauri A. Ditzler,
Within the framework of a laboratory-focused, guided-inquiry pedagogy, students discover the Nernst equation, the spontaneity of galvanic cells, concentration cells, and the use of electrochemical data to calculate equilibrium constants.
Mills, Kenneth V.; Herrick, Richard S.; Guilmette, Louise W.; Nestor, Lisa P.; Shafer, Heather;Ditzler, Mauri A. J. Chem. Educ. 2008, 85, 1116.
Electrochemistry |
Electrolytic / Galvanic Cells / Potentials |
Equilibrium
Discovering the Thermodynamics of Simultaneous Equilibria. An Entropy Analysis Activity Involving Consecutive Equilibria  Thomas H. Bindel
This activity explores the thermodynamics of simultaneous, consecutive equilibria and is appropriate for second-year high school or AP chemistry. Students discover that a reactant-favored (entropy-diminishing) reaction can be caused to happen if it is coupled with a product-favored reaction of sufficient entropy production.
Bindel, Thomas H. J. Chem. Educ. 2007, 84, 449.
Acids / Bases |
Equilibrium |
Thermodynamics
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
The Reaction Quotent Is Unnecessary To Solve Equilibrium Problems. The Limitation of a Qualitative Reasoning—Editor's Note  John W. Moore
Discusses the relationship between the concentration of an aqueous solution of acetic acid, its ion concentration, and its equivalent conductance.
Moore, John W. J. Chem. Educ. 2006, 83, 384.
Aqueous Solution Chemistry |
Equilibrium |
Conductivity |
Mathematics / Symbolic Mathematics
The Reaction Quotent Is Unnecessary To Solve Equilibrium Problems. The Limitation of a Qualitative Reasoning  Rob Lederer
Discusses the relationship between the concentration of an aqueous solution of acetic acid, its ion concentration, and its equivalent conductance.
Lederer, Rob. J. Chem. Educ. 2006, 83, 384.
Aqueous Solution Chemistry |
Equilibrium |
Mathematics / Symbolic Mathematics |
Conductivity
The Reaction Quotent Is Unnecessary To Solve Equilibrium Problems. The Limitation of a Qualitative Reasoning  Paul Matsumoto
Discusses the relationship between the concentration of an aqueous solution of acetic acid, its ion concentration, and its equivalent conductance.
Matsumoto, Paul. J. Chem. Educ. 2006, 83, 383.
Equilibrium |
Mathematics / Symbolic Mathematics |
Aqueous Solution Chemistry |
Conductivity
The Reaction Quotent Is Unnecessary To Solve Equilibrium Problems. The Limitation of a Qualitative Reasoning  Michiel Vogelezang
Discusses the relationship between the concentration of an aqueous solution of acetic acid, its ion concentration, and its equivalent conductance.
Vogelezang, Michiel. J. Chem. Educ. 2006, 83, 383.
Aqueous Solution Chemistry |
Equilibrium |
Mathematics / Symbolic Mathematics |
Conductivity
The Reaction Quotent Is Unnecessary To Solve Equilibrium Problems. The Limitation of a Qualitative Reasoning  Michiel Vogelezang
Discusses the relationship between the concentration of an aqueous solution of acetic acid, its ion concentration, and its equivalent conductance.
Vogelezang, Michiel. J. Chem. Educ. 2006, 83, 383.
Aqueous Solution Chemistry |
Equilibrium |
Mathematics / Symbolic Mathematics |
Conductivity
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
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
The Reaction Quotient Is Unnecessary To Solve Equilibrium Problems: No Problems with Q  Robert Lederer
Mr. Matsumotos 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
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
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
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
Reaction to Why Do We Teach Equilibrium Calculations?  Stephen J. Hawkes
"Rigor" in introductory chemistry is often equated with quantitation. Consequently the understanding of chemical reactions and properties is obscured. This was illustrated by Stumpo who asked students to calculate ?E of a reaction, and then on another question on the same test asked a question aimed at its meaning. 77% of the students calculated correctly, but only 24% showed understanding of its meaning. The ability to calculate a number does not measure understanding of the number.
Hawkes, Stephen J. J. Chem. Educ. 2004, 81, 1265.
Equilibrium |
Chemometrics
Reaction to Why Do We Teach Equilibrium Calculations?   Don L. Lewis
A recently published correspondence by Stephen J. Hawkes on teaching equilibrium calculations troubles me. Hawkes dismisses equilibrium calculations as mere algorithms, best deferred until the student can use computer programs. I find it difficult to believe that a computer program enhances understanding. From a chemists point of view, the equilibrium condition is a limit, a limit that (because of stochastic considerations) does not exist. It might be better to make the reaction quotient statement using < or > but the use of those relations is delayed until quantum mechanics.
Lewis, Don L. J. Chem. Educ. 2004, 81, 1265.
Equilibrium |
Chemometrics
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 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
The Nernst Equation: Determination of Equilibrium Constants for Complex Ions of Silver  Martin L. Thompson and Laura J. Kateley
The experiment requires a voltmeter capable of recording millivolts (or a good pH meter) and inexpensive chemicals. It allows students to check the validity of the Nernst equation and compare their experimental Kform values to reported ones.
Thompson, Martin L.; Kateley, Laura J. J. Chem. Educ. 1999, 76, 95.
Equilibrium |
Coordination Compounds |
Electrochemistry |
Oxidation / Reduction
Teaching Chemical Equilibrium and Thermodynamics in Undergraduate General Chemistry Classes  Anil C. Banerjee
Discussion of the conceptual difficulties experienced by undergraduates when dealing with equilibrium and thermodynamics, along with teaching strategies for dealing with these difficulties.
Banerjee, Anil C. J. Chem. Educ. 1995, 72, 879.
Equilibrium |
Thermodynamics
Will a precipitate form? Will it dissolve?: The Role of Lecture Demonstrations in Facilitating the Introduction to Solubility Product Equilibria  Pacer, Richard A.; Williams, Kathryn
Three demonstrations to illustrate solubility product equilibria.
Pacer, Richard A.; Williams, Kathryn J. Chem. Educ. 1994, 71, 69.
Precipitation / Solubility |
Aqueous Solution Chemistry |
Equilibrium
Demonstration of the Common Ion Effect  Koubek, E.
KCl and HCl are used in this demonstration to describe the common ion effect and to show the difference between values Q and K.
Koubek, E. J. Chem. Educ. 1993, 70, 155.
Solutions / Solvents |
Equilibrium
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
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