Issue Date: October 31, 2011
AP Chemistry ‘Big Ideas’ Fail Reality Tests
To claim “all matter can be understood in terms of arrangements of atoms” (C&EN, Sept. 12, page 54) fails to acknowledge that most matter and mass in the universe are not atomic (Science, DOI: 10.1126/science.1085976). The implications of this for chemistry teachers are discussed in papers in the Journal of Chemical Education (DOI: 10.1021/ed073p1073 and 10.1021/ed076p353). Certainly neutron stars, black holes, dark matter, and dark energy are not arrangements of atoms or molecules.
Furthermore, many terrestrial reactions alter the identity of atoms involved. One example is cosmic-ray neutrons transmuting atmospheric nitrogen (isotope 14) to carbon-14, which produces radioactive 14C, and thereby provides the basis of carbon dating.
Neutron absorption activates (that is, makes radioactive) and thereby transmutes many atomic species from natural neutron emitters in the earth, from nuclear reactors, and also from an analytical technique called neutron activation analysis (Anal. Chem., DOI: 10.1021/ac60149a017).
Cosmic and solar neutrinos also transmute multiple types of atoms, for example, chlorine to argon—previously used in solar neutrino detectors—but these reactions continue to occur in oceans, continents, our bodies, and so on. These reactions are regarded by many as chemistry, since they change the elemental (chemical) name of the atoms involved. If so, then the statement in the C&EN article that “atoms retain their identity in chemical reactions” is invalid.
If chemical reactions were to be defined as processes in which reacting atoms retain their identity, then chemistry is one of many sets of natural and industrial processes that alter the atomic and molecular forms of matter, some identified above. And universality for one set should not be claimed. Defining chemistry this way would also seem to exclude the work of many who now call themselves chemists.
Motivating Advanced Placement chemistry students is a challenge we appreciate, but using distorted claims seems inappropriate.
By Sarah Brooke
Jay S. Huebner
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