Cart
Article
A Closer Look at the Addition of Equations and Reactions
Hi-Res PDFPurchase the full-text
- PDF/HTML,
figures/images,
references and tables,
(where available)
Abstract
Chemists occasionally find it convenient or even necessary to express an overall reaction as the sum of two or more component reactions. We add chemical equations as if they were algebraic equations, even to the point of cancelling out terms (actually quantities of chemical reagents) that appear on both sides. This amounts to assuming that the plus sign has the same significance in both kinds of equations, and that the arrows we customarily use in chemistry are simply a variation on the equals sign with no significant difference in meaning. A close examination, however, reveals that the resemblance between chemical algebraic equations is entirely superficial, and that the real meaning of addition in chemical equations is subtle and varies from case to case. In high-school courses, students are likely to encounter the addition of equations in thermochemistry, in electrochemistry, and in kinetics. This article looks into a few examples drawn from these three branches of chemistry.
See Letter re: this article.
Keywords (Audience):
High School / Introductory ChemistryKeywords (Feature):
Applications and AnalogiesKeywords (Subject):
Calorimetry / ThermochemistryCiting Articles
Citation data is made available by participants in CrossRef's Cited-by Linking service. For a more comprehensive list of citations to this article, users are encouraged to perform a search in SciFinder.
This article has been cited by 2 ACS Journal articles (2 most recent appear below).
Reactions (→) vs Equations (=)
S. R. LoganJournal of Chemical Education2003 80 (11), 1258Reactions (→) vs Equations (=)
S. R. LoganJournal of Chemical Education2003 80 (11), 1258Commentary on the distinction between chemical reactions and equations.
The Relationship between Stoichiometry and Kinetics
Sidney TobyJournal of Chemical Education2000 77 (2), 188The Relationship between Stoichiometry and Kinetics
Sidney TobyJournal of Chemical Education2000 77 (2), 188A mechanism consisting of several elementary steps may not have a unique stoichiometry. Even if one exists, a linear combination of the steps will not in general lead to a correct formulation of the overall stoichiometry. We consider the time dependence ...
Tools
-
Add to Favorites
-
Download Citation
-
Email a Colleague -
Permalink
Order Reprints
Rights & Permissions
Citation Alerts
History
- Received: August 03, 2009
ACS
Network
Facebook
Tweet This
CiteULike
Newsvine
Digg This
Delicious
