Activity Number 44

	Overview and Learning Objectives
	Classroom Practice
	Central Concepts
	Textbook References
	Activity Credits
	Requirements

Chemical Reaction Kinetics: Dissociation and Recombination of Diatomic Molecules (Demo)

Interactive model, with minimal support

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	Overview and Learning Objectives This model shows the dissociation and recombination of diatomic molecules. When the temperature rises, the diatomic bonds start to break, resulting in free radicals. When the temperature drops, the free radical starts to recombine and form diatomic bonds again. To provide the energy for dissociation and maintain the thermal stability of the recombined molecules, a heat bath is applied. This model can be used to explain a class of reactions, such as O2-->2O, H2-->2H. return to top



	Classroom Practice A metaphor for students? Chemical reactions can be regarded as the processes of changing partners of atoms. A partnership between a pair of atoms is typically a covalent bond. The collision theory suggests that atoms bind with others, or lose partners, or swap partners, or do nothing when they collide. return to top



	Central Concepts Key Concept: Chemical reactions result from making and breaking chemical bonds. The number of each kind of atom in a reaction remains constant. There are two types of two-body elementary reactions: breaking and making a bond. The rule for breaking a bond is simple: a bond is broken only when enough energy is given to a bonded party for escaping the potential well formed by its binding partner. Diatomic molecules that disassociate create free radicals. Free radicals react easily with molecules and other radicals. Additional Related Concepts Physics/Chemistry Association Breaking bonds Range of reactions Reaction rate return to top



	Textbook References Biology: Concepts and Connections (Pearson) 5th Edition - Chapter 5: The Working Cell BSCS Blue (8th Edition) - Chapter 12: Reproduction BSCS Blue (8th Edition) - Chapter 2: Energy, Life and the Biosphere BSCS Human - Chapter 9: The Cycling of Matter and the Flow of Energy in Communities Cell Biology (Pollard and Earnshaw) Saunders 2002 - Chapter Three: Basic Biophysical Concepts Web of Life - Chapter 4: Photosynthesis and Cellular Respiration return to top



	Activity Credits Created by CC Project: CCATOMS using Molecular Workbench return to top



	Requirements Java 1.5+ - Java 1.5+ is available for Windows, Linux, and Mac OS X 10.4 and greater. If you are using Mac OS X 10.3, you can download MW Version 1.3 and explore within it instead. return to top

These materials are based upon work supported by the
National Science Foundation under grant number DUE-0402553

Any opinions, findings, and conclusions
or recommendations expressed in this material are those of
the author(s) and do not necessarily reflect the views
of the National Science Foundation.

Chemical Reaction Kinetics: Dissociation and Recombination of Diatomic Molecules (Demo)

Overview and Learning Objectives

Classroom Practice

Central Concepts

Additional Related Concepts

Textbook References

Activity Credits

Requirements