JCE Online Journal of Chemical Education
 | Subscriptions  | Software Orders  | Support  | Contributors  | Advertisers  | 

JCE Print

JCE Digital Library

JCE Software

Only@JCE Online

About JCE


  Home > JCE Print > Journal of Chemical Education > Issues > 2002  > March  >
Research: Science and Education
Statistical Study of Distribution Diagrams for Two-Component Systems: Relationships of Means and Variances of the Discrete Variable Distributions with Average Ligand Number and Intrinsic Buffer Capacity
Rosario Moya-Hernández and Juan Carlos Rueda-Jackson
Sección de Química Analítica, Universidad Nacional Autónoma de México, Cuautitlán Izcalli, México; and Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, 09340 México, D.F., México

María Teresa Ramírez and Guillermo A. Vázquez
Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, 09340 México, D.F., México

Josef Havel
Department of Analytic Chemistry, Masaryk University, Brno, Czech Republic

Alberto Rojas-Hernández
Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, 09340 México, D.F., México

Cover
March 2002
Vol. 79 No. 3
p. 389

Abstract
The lack of emphasis on the analogy between mathematical statistical distributions and physicochemical distributions in statistical teaching in chemistry courses may be due to a lack of application examples. This paper demonstrates that what is known as a distribution diagram for a two-component polydonor system (MLn/.../ML/M/L) is the set of molar fraction distributions of M species as functions of stoichiometric coefficients of L, formally defining a molecular isotopy. The correspondence between the set of means of these distributions of a discrete variable with the average ligand number and the equivalence between the set of its variances with the intrinsic buffer capacity of the polydonor system is shown. The particular case of phosphates in water is presented. This view of distribution diagrams could help teachers of mathematical statistics to illustrate the fundamental notions of mathematical distributions of discrete variables with chemical application examples.
Supplement
Mathematical demonstration of the relationships discussed in this paper is available.
*  Contents JCE2002p0389W1.doc (Microsoft Word) and JCE2002p0389W2.xls (Microsoft Excel)
*  Download
JCE2002p0389W.pdf

JCE2002p0389W.zip

JCE2002p0389W.sit

More Information
*  Citation
Moya-Hernández, Rosario; Rueda-Jackson, Juan Carlos; Ramírez, María Teresa; Vázquez, Guillermo A.; Havel, Josef; Rojas-Hernández, Alberto. J. Chem. Educ. 2002 79 389.
*  Keywords
Acid-Base Chemistry; Demonstrations; Solutions / Solvents; Statistics / Data Analysis; Thermodynamics
*  History
Created:
Last Updated:
January 31, 2002
March 16, 2005
  Home > JCE Print > Journal of Chemical Education > Issues > 2002  > March  > Page 389


Subscriptions

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.