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 TwoWeek 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 laboratoryfocused, guidedinquiry 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 secondyear high school or AP chemistry. Students discover that a reactantfavored (entropydiminishing) reaction can be caused to happen if it is coupled with a productfavored 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 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

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. Matsumotos students are to be congratulated for discerning an interesting mathematical procedure. Exclusively utilizing this algorithm, however, shortcuts 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 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

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 chemists 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

PlayingCard Equilibrium Robert M. Hanson A simple handson 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 Chtelier'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 nonunity 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

