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

JCE Print
   Current Issue
 Previous Issues
 Supplements
 Search JCE Index

JCE Digital Library
   DigiDemos
 QBank
 SymMath
 WebWare

JCE Software
   Latest Releases
 Software & Video
 Downloads
 Support

Only@JCE Online
   JCE Online Store
 JCE HS CLIC
 JCE Discussion Forums
   Biographical Snapshots
 ChemEd Resource Shelf
 Featured Molecules
 Hal's Picks
 Project Chemlab
 Reviewed WWW Sites
 "Web-Ed" Articles

About JCE
   Features
 Publications
 Operations
 Outreach
 Contact Us


  Home > JCE Print > Journal of Chemical Education > Issues > 1999  > October  >
Research: Science and Education
Chemical Kinetics in Constant-Pressure Systems
P. L. Corio
University of Kentucky, Department of Chemistry, Lexington, KY 40506-0055
Cover
October 1999
Vol. 76 No. 10
p. 1452
Abstract
A theory is developed for treating chemical kinetics in nonflow, constant-pressure systems. The procedure is straightforward and applicable to systems in which several reactions occur, subject to any given rate laws. A significant difference from kinetics at constant volume is that the varying volume precludes the use of concentrations to express the conservation conditions. Instead the conservation conditions must be expressed in terms of the moles of components and converted to concentrations when the relation between volume and concentration is established. The theory is applied to reactions in ideal systems for zero-, first-, and second-order reactions, permitting an immediate comparison with the corresponding rate laws in constant-volume kinetics. In each of these constant pressure systems, a stationary state is possible in which the concentration of a reactant does not appear to exhibit a change of concentration; that is, the decrease in its concentration is exactly compensated by the decrease in volume. A similar stationary state is also possible for the concentration of a product. Both cases can be experimentally realized by specialization of the initial conditions, though both stationary states are unstable. Finally, for rate laws of the form r = k[A]a[B]b[C]c, there is an apparent linear variation of the rate constant with concentration.
More Information
*  Citation
 Corio, Paul L. J. Chem. Educ. 1999 76 1452.
*  Keywords
 Physical Chemistry; Chemical Education Research; Kinetics; Mechanisms; Theoretical Chemistry; Teaching/Learning Theory/Practice
*  History
 Created:
Last Updated:		 September 6, 1999
June 23, 2005
<< Previous Article Table of Contents Next Article >>
  Home > JCE Print > Journal of Chemical Education > Issues > 1999 > October > Page 1452


Subscriptions
 Subscription Info
 Order Forms

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.
 JCE HS CLIC

Contributions Welcome
JCE welcomes your submission
 Contributors' Corner

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.
 Recent Advertisers

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.
 Outreach with JCE

Comments to
jceonline@chem.wisc.edu		 Copyright © Division of Chemical Education, Inc., American Chemical Society.
All rights reserved.