A Closer Look at the Addition of Equations and Reactions

• Damon Diemente ^[1]
  1. [1] Trinity School
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 75, Nº 3 (March), 1998, págs. 319-321
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • 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.