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 > 2005  > February  >
In the Classroom
Sublimination of Iodine at Various Pressures: Mutlipurpose Experiments in Inorganic and Physical Chemistry
Ilya A. Leenson
Department of Chemistry, Moscow State University, Moscow 119899, Russia
Cover
February 2005
Vol. 82 No. 2
p. 241
Abstract
The aim of this article is to elucidate some interesting phenomena, which can be observed in the process of heating solid iodine in closed vessels at various pressures. The experiments provide useful possibilities for discussing the following items: vaporization and melting of iodine crystals at atmospheric pressure; long storage of iodine crystals in air and in vacuum; temperature at which iodine vapors above crystals in a closed vessel becomes visible; the rate of iodine sublimation in high vacuum; “jumping” of heated iodine crystal in vacuum and “jet force” which emerges at different temperatures; diffusion of iodine vapors and “random walk” of iodine molecules; experimental determination of mean free path and collision frequency; mean free path in real life; calculation of the number of iodine atoms in equilibrium with molecular iodine at boiling point; and safety considerations (strength of glass ampules of different diameters against internal and external pressure). The article and questions therein may be used in classroom discussion with students of the general, inorganic, and physical chemistry (molecular-kinetic theory).
Supplement

Video 1. Iodine in a closed vessel is liquified then cooled.

 

Video 2. Iodine crystals in a sealed, evacuated vessel are gently heated over a hot plate.

 

Video 3. The vessel is placed in room temperature water, and the walls of the vessel heated.

Video 4. The vessel is allowed to cool.

*  Contents
*  Download
More Information
*  Citation
 Leenson, Ilya A. J. Chem. Educ. 2005 82 241.
*  Keywords
 Demonstrations; Descriptive Chemistry; Diffusion; Gases; General Chemistry; Iodine; Phase Transitions / Diagrams; Physical Chemistry; Physical Properties; Problem-Based Learning
*  History
 Created:
Last Updated:		 January 4, 2005
January 12, 2005
<< Previous Article Table of Contents Next Article >>
  Home > JCE Print > Journal of Chemical Education > Issues > 2005  > February  > Page 241


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.