|
|
| Home > JCE Print > Journal of Chemical Education > Issues >
2003
>
September
> |
|
In the Classroom
|
|
|
|
Multiple Linear Least-Squares Fits with a Common Intercept: Determination of the Intrinsic Viscosity of Macromolecules in Solution
|
M. C. López Martínez, F. G. Díaz Baños, A. Ortega Retuerta, and J. García de la Torre
Departamento de Química Física, Facultad de Química, Universidad de Murcia, 30071 Murcia, Spain
|
|
September 2003
Vol. 80 No. 9
p. 1036
|
|
|
|
|
|
|
| Abstract |
|
A procedure, based on the least-squares principle for simultaneously fitting two or more linear data sets with a common intercept, is described. Expressions are derived to calculate the common intercept and the slopes. The procedure is applied to several laboratory experiments. Particularly, this procedure is employed in the measurement of the intrinsic viscosity, which expresses the concentration dependence of the viscosity of a dilute polymer solution. The intrinsic viscosity is determined by extrapolation to zero concentration of a polymer quantity that involves the solution viscosity and concentration. The extrapolation can be done by two procedures, associated with the names of Huggins and Kraemer, both yielding the intrinsic viscosity as the common intercept. A numerical procedure, implemented with the computer program VISFIT was devised. This procedure is employed for the data analysis in the determination of intrinsic viscosities.
|
| Supplement |
VISFIT for Linux and Microsoft MSDOS/Windows platform, along with sample input and output is available. A document that describes the details of the experimental measurements and the use of VISFIT for data analysis is also available.
|
 Contents |
Folder JCE2003p1036W containing Visfit1a-lnx.exe (Linux) and Visfit1a-msd.exe (MSDOS/Windows)
|
| Download |
|
|
| More Information |
Citation |
López Martínez, M C.; Díaz Baños, F. G.; Ortega Retuerta, A.; García de la Torre, J. J. Chem. Educ. 2003 80 1036.
|
Keywords |
Biophysical Chemistry; Physical Chemistry; Polymer Chemistry; Solutions / Solvents; Statistics / Data Analysis
|
History |
Created:
Last Updated: |
August 4, 2003
February 28, 2005
|
|
|
|
|
|
| Home > JCE Print > Journal of Chemical Education > Issues >
2003
>
September
> Page
1036
|
|
|
| JCE HS CLIC |
|
Our Secondary School editors work hard to distill all the JCE materials to produce a fraction of particular interest to high school teachers. We call it CLIC.
|
| Contributions Welcome |
| JCE welcomes your submission |
| Advertisers |
| In recent years we have worked hard to better match our advertisers with our readers. When shopping for chemistry education materials, visit our advertisers' WWW sites first. |
| Be An Ambassador |
| Take JCE along on your outreach missions. Copies of the Journal, guest access to JCE Online, our publications catalog, and more are available for your participants. |
|
