JCE Software, 1D1: Equilibrium Calculator

Equilibrium Calculator

Robert D. Allendoerfer
State University of New York at Buffalo, Buffalo, NY 14214-3094

Note:
This program is included in both the General Chemistry Collection (SP-16) and the Advanced Chemistry Collection (SP-28).

To Order General Chemistry Collection
To Order Advanced Chemistry Collection

Equilibrium Calculator, adapted from a previously published computer program (1), has the potential to eliminate quadratic equations from general chemistry books as calculators have eliminated logarithm tables. Many current textbooks limit the discussion of the calculation of equilibrium concentrations to a few carefully chosen examples that can be treated using only second order polynomials, e.g., PCl₅ = PCl₃ + Cl₂, because these are the only type of problems that students can solve exactly.
Equilibrium Calculator can calculate the equilibrium concentrations of all the reagents in an arbitrary chemical reaction with as many as five reactants and products:

a A + b B + c C + d D + e E = v V + w W + x X + y Y + z Z
without the necessity of solving polynomial equations. The program works by minimizing the Gibbs free energy as a function of the extent of reaction using an iterative algorithm. This method for single step equilibria (2, 3) has been extended to competing and coupled reactions (4).
The input data are

The stoichiometric coefficients in the balanced equation
The initial concentrations of the chemical species
The equilibrium constant, Kc.
Thus by using this program, chemically relevant examples such as the production of ammonia from nitrogen and hydrogen, can be introduced into general chemistry without regard to mathematical difficulty.
The program uses the same algorithms and has the same functionality as the previously published DOS version (5). The advantages over the DOS version are those of the Windows interface: integrated mouse support, on-line help files, and the ability to vary screen colors and printer fonts through the use of an initiation file.
Hardware and Software Requirements
Series D of JCE: Software requires Microsoft Windows version 3.0 or later and associated hardware as defined by Microsoft. We recommend an IBM-PC/AT, PS/2, or compatible computer with a 80386 or higher processor, a minimum of 4 MB of memory, a hard disk, one floppy disk drive to install the software, and a Windows-compatible graphics card, such as an IBM VGA or a Super VGA adapter with a compatible color monitor, and a mouse. DOS version 5.0 or later is highly recommended.
Equilibrium Calculator requires only the software and hardware listed above, but for complicated equilibria may benefit from a math coprocessor.
Literature Cited

Campanario, J. M. and Ballesteros, R., J. Comp. Math. Sci. Teaching, 1991, 10 (2), 87.
Weltin, E. J. Chem. Educ., 1990, 67 (7), 548.
Weltin, E. J. Chem. Educ., 1991, 68( 6), 486.
Weltin, E. J. Chem. Educ., 1992, 69 (5), 393.
Allendoerfer, R. J. Chem. Educ.: Software, 1992, V B (2).

First Published: June 1993
Citation: Allendoerfer, R. D. Equilibrium Calculator J. Chem. Educ. Software 1D1
Keywords: Lecture Aid; Computer Room; Laboratory; Simulation; Instructor; High School; General; Analytical; Physical; Equilibrium calculations

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JCE Online | Journal | Software | Internet | Happenings | About JCE | Contact JCE

Last Updated: July 19, 2001
Created: December 4, 1996 Created by: J. L. Holmes
Comments to: jceonline@chem.wisc.edu

© 1997 Division of Chemical Education, Inc., American Chemical Society. All rights reserved.



Equilibrium Calculator
Robert D. Allendoerfer State University of New York at Buffalo, Buffalo, NY 14214-3094

Note:	This program is included in both the General Chemistry Collection (SP-16) and the Advanced Chemistry Collection (SP-28). To Order General Chemistry Collection To Order Advanced Chemistry Collection

Equilibrium Calculator, adapted from a previously published computer program (1), has the potential to eliminate quadratic equations from general chemistry books as calculators have eliminated logarithm tables. Many current textbooks limit the discussion of the calculation of equilibrium concentrations to a few carefully chosen examples that can be treated using only second order polynomials, e.g., PCl₅ = PCl₃ + Cl₂, because these are the only type of problems that students can solve exactly. Equilibrium Calculator can calculate the equilibrium concentrations of all the reagents in an arbitrary chemical reaction with as many as five reactants and products: a A + b B + c C + d D + e E = v V + w W + x X + y Y + z Z without the necessity of solving polynomial equations. The program works by minimizing the Gibbs free energy as a function of the extent of reaction using an iterative algorithm. This method for single step equilibria (2, 3) has been extended to competing and coupled reactions (4). The input data are The stoichiometric coefficients in the balanced equation The initial concentrations of the chemical species The equilibrium constant, Kc. Thus by using this program, chemically relevant examples such as the production of ammonia from nitrogen and hydrogen, can be introduced into general chemistry without regard to mathematical difficulty. The program uses the same algorithms and has the same functionality as the previously published DOS version (5). The advantages over the DOS version are those of the Windows interface: integrated mouse support, on-line help files, and the ability to vary screen colors and printer fonts through the use of an initiation file. Hardware and Software Requirements Series D of JCE: Software requires Microsoft Windows version 3.0 or later and associated hardware as defined by Microsoft. We recommend an IBM-PC/AT, PS/2, or compatible computer with a 80386 or higher processor, a minimum of 4 MB of memory, a hard disk, one floppy disk drive to install the software, and a Windows-compatible graphics card, such as an IBM VGA or a Super VGA adapter with a compatible color monitor, and a mouse. DOS version 5.0 or later is highly recommended. Equilibrium Calculator requires only the software and hardware listed above, but for complicated equilibria may benefit from a math coprocessor. Literature Cited Campanario, J. M. and Ballesteros, R., J. Comp. Math. Sci. Teaching, 1991, 10 (2), 87. Weltin, E. J. Chem. Educ., 1990, 67 (7), 548. Weltin, E. J. Chem. Educ., 1991, 68( 6), 486. Weltin, E. J. Chem. Educ., 1992, 69 (5), 393. Allendoerfer, R. J. Chem. Educ.: Software, 1992, V B (2).


News \| Issues \| CD-ROM / Video \| Find It! \| Technical Support \| For Authors
JCE Online \| Journal \| Software \| Internet \| Happenings \| About JCE \| Contact JCE

Last Updated: July 19, 2001 Created: December 4, 1996	Created by: J. L. Holmes Comments to: jceonline@chem.wisc.edu

© 1997 Division of Chemical Education, Inc., American Chemical Society. All rights reserved.