van der Waals and Redlich Kwong: Fitting Two Parameter Equations to Gas Data©
Theresa Julia Zielinski
Department of Chemistry, Medical Technology, and Physics
Monmouth University
West Long Branch, NJ 07764-1898
United States
mail to: tzielins@monmouth.edu



Abstract
The Mathcad document given here is a highly annotated application of non-linear curvefitting for determining the a and b parameters for the van der Waals and Redlich-Kwonge quations. The document goes through the development of the sum of squares of deviations SSD, applies the Minerr function to minimize the SSD and then uses the F-test to determine the equation that best represents the data. The determination of the standard deviation of the fitting parameters is done through the explicit construction and inversion of the Hessian matrix. The treatment here is more extensive than found in most texts. References are included. A suggestion is included for students to use to show mastery of the skills learned by using the document. The document is a solution to the problem presented in the play "It's a Gas!" The "It's a Gas" play and instructional materials can also be found at this site. The "It's a Gas" project is one of several context-rich physical chemistry projects being developed by the Physical Chemistry On Line Consortium. This document was created with Mathcad 6.0 Plus. It will work with higher versions of Mathcad but you may need to check the read statement. Be sure to copy the datafile for the calculation in the document.
Keywords
Audiences: Upper-Division Undergraduate
Pedagogies: Computer-Based Learning
Domains: Physical Chemistry
Topics: Chemometrics, Gases, Mathematics / Symbolic Mathematics
Documents
File NameDescriptionSoftware TypeSoftware Version
realgas.mcd Mathcad Computational Document Mathcad 6
realgas11.mcd Mathcad Computational Document Mathcad 11
n2data1.prn Data must be in the same directory as the Mathcad template.
realgas.pdf Read Only Document
Comments to: Theresa Julia Zielinski, tzielins@monmouth.edu
©Copyright Theresa Julia Zielinski, 1996. All rights reserved. You are welcome to use this document in your own classes but commercial use is not allowed without the permission of the author.