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Journal Articles: 31 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 Use of Limits in an Advanced Placement Chemistry Course  Paul S. Matsumoto, Jonathan Ring, and Jia Li (Lily) Zhu
This article describes the use of limits in topics usually covered in advanced placement or first-year college chemistry. This approach supplements the interpretation of the graph of an equation since it is usually easier to evaluate the limit of a function than to generate its graph.
Matsumoto, Paul S.; Ring, Jonathan; Zhu, Jia Li (Lily). J. Chem. Educ. 2007, 84, 1655.
Acids / Bases |
Equilibrium |
Gases |
Mathematics / Symbolic Mathematics |
Thermodynamics
Flame Emission Spectrometry in General Chemistry Labs: Solubility Product (Ksp) of Potassium Hydrogen Phthalate  Frazier W. Nyasulu, William Cusworth III, David Lindquist, and John Mackin
In this general chemistry laboratory, flame emission spectrometry is used to determine the potassium ion concentration in saturated solutions of potassium hydrogen phthalate. From these data the solubility products, the Gibbs free energies of solution, the standard enthalpy of solution, and the standard entropy of solution are calculated.
Nyasulu, Frazier W.; Cusworth, William, III; Lindquist, David; Mackin, John. J. Chem. Educ. 2007, 84, 456.
Acids / Bases |
Atomic Properties / Structure |
Spectroscopy |
Equilibrium |
Quantitative Analysis |
Thermodynamics |
Titration / Volumetric Analysis |
Solutions / Solvents |
Aqueous Solution Chemistry |
Atomic Spectroscopy
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
Using Computer Simulations To Teach Salt Solubility. The Role of Entropy in Solubility Equilibrium  Victor M. S. Gil and João C. M. Paiva
Pairs of salts are discussed to illustrate the interpretation of their different behavior in water in terms of the fundamental concept of entropy. The ability of computer simulations to help improve students' understanding of these chemistry concepts is also examined.
Gil, Victor M. S.; Paiva, João C. M. J. Chem. Educ. 2006, 83, 170.
Computational Chemistry |
Equilibrium |
Thermodynamics |
Solutions / Solvents |
Precipitation / Solubility
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
Microscopic Description of Le Châtelier's Principle  Igor Novak
The analysis based on microscopic descriptors (energy levels and their populations) is given that provides visualization of free energies and conceptual rationalization of Le Châtelier's principle. The misconception "nature favors equilibrium" is highlighted.
Novak, Igor. J. Chem. Educ. 2005, 82, 1190.
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: 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
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
Rubber Bands, Free Energy, and Le Châtelier's Principle  Warren Hirsch
Using a rubber band to illustrate Gibbs free energy, entropy, and enthalpy.
Hirsch, Warren. J. Chem. Educ. 2002, 79, 200A.
Noncovalent Interactions |
Thermodynamics |
Equilibrium
Determination of Ksp, ΔG0, ΔH0, and ΔS0 for the Dissolution of Calcium Hydroxide in Water: A General Chemistry Experiment  William B. Euler, Louis J. Kirschenbaum, and Ben Ruekberg
This exercise utilizes low-cost, relatively nonhazardous materials presenting few disposal problems. It reinforces the students' understanding of the interrelationship of solubility, Ksp, ΔG0, ΔH0, and ΔS0.
Euler, William B.; Kirschenbaum, Louis J.; Ruekberg, Ben. J. Chem. Educ. 2000, 77, 1039.
Equilibrium |
Thermodynamics |
Titration / Volumetric Analysis
Chemical Equilibrium (the author replies)  Banerjee, Anil
Item 7 deserves a fuller answer than was provided.
Banerjee, Anil J. Chem. Educ. 1996, 73, A262.
Equilibrium |
Thermodynamics
Chemical Equilibrium  Logan, S. R.
Item 7 deserves a fuller answer than was provided.
Logan, S. R. J. Chem. Educ. 1996, 73, A261.
Equilibrium |
Thermodynamics
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
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
REACT: Exploring Practical Thermodynamic and Equilibrium Calculations  Ramette, Richard W.
Description of REACT software to balance complicated equations; determine thermodynamic data for all reactants and products; calculate changes in free energy, enthalpy, and entropy for a reaction; and find equilibrium conditions for the a reaction.
Ramette, Richard W. J. Chem. Educ. 1995, 72, 240.
Stoichiometry |
Equilibrium |
Thermodynamics |
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
A simple explanation of the salt water oscillator  Noyes, Richard M.
Yoshikawa et al. have described a simple device that undergoes repeated oscillations and that can also illustrate some of the principles essential to the oscillators driven by chemical reactions.
Noyes, Richard M. J. Chem. Educ. 1989, 66, 207.
Laboratory Equipment / Apparatus |
Thermodynamics |
Equilibrium
Thermodynamics of the rhodamine B lactone zwitterion equilibrium: An undergraduate laboratory experiment  Hinckley, Daniel A.; Seybold, Paul G.
An experiment to derive thermodynamic values from a thermochromic equilibrium that uses a commercially available dye, attains equilibrium rapidly, and employs a simple, single-beam spectrophotometer.
Hinckley, Daniel A.; Seybold, Paul G. J. Chem. Educ. 1987, 64, 362.
Thermodynamics |
Dyes / Pigments |
Spectroscopy |
Equilibrium
Thermodynamic changes, kinetics, equilibrium, and LeChatelier's principle  Hansen, Robert C.
A series of demonstrations in which water in beakers and the flow of water between beakers is used to represent the components of an exothermic chemical reaction and the flow and quantity of thermal energy involved in chemical changes.
Hansen, Robert C. J. Chem. Educ. 1984, 61, 804.
Equilibrium |
Kinetics |
Thermodynamics
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
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
A simple analogy of the relationship of ?G to the position of equilibrium  Marks, D. J.
This short note describes a simple demonstration to serve as an analogy of the relationship of ?G to the position of equilibrium.
Marks, D. J. J. Chem. Educ. 1967, 44, 402.
Thermodynamics |
Equilibrium
Concerning equilibrium, free energy changes, LeChatelier's Principle. III. Halide-halate equilibria  Eberhardt, William H.
Compares four equilibria: KI + KIO3, KI + KBrO3, KBR + KBrO3, and KBr + KIO3.
Eberhardt, William H. J. Chem. Educ. 1964, 41, A883.
Equilibrium |
Aqueous Solution Chemistry |
Thermodynamics
Concerning equilibrium, free energy changes, Le Châtelier's principle II  Eberhardt, William H.
This demonstration involves a reversible, temperature-based transformation from blue tetrahedrally coordinated Co2+ to pink sixfold coordinated Co2+.
Eberhardt, William H. J. Chem. Educ. 1964, 41, A591.
Equilibrium |
Thermodynamics |
Aqueous Solution Chemistry |
Coordination Compounds
Concerning equilibrium, free energy changes, Le Chtelier's principle  Eberhardt, William H.
Aqueous KI is added to a solution of CuSO4 in a separatory funnel; adding more CuSO4 demonstrates an equilibrium sift.
Eberhardt, William H. J. Chem. Educ. 1964, 41, A477.
Equilibrium |
Thermodynamics |
Reactions
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
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