Determining the Carbon-Carbon Distance in an Organic Molecule with a Ruler.

This article describes how to estimate the carbon–carbon bond distance for the naphthalene molecule. The fundamental idea of this procedure is based on the well-known experimental determination of Avogadro's number using an oil, such as oleic acid. The experimental results are good and the cost of the experiment is negligible. All the products and objects used can be obtained at home or purchased for little cost. The procedure is easily performed and can be done either at home or in classroom, with the restriction that the mass of the naphthalene must be determined using an analytical or, at least, a precise balance. If there is not an appropriate balance, a neighborhood pharmacist could help weigh the samples. Before performing the experiment, it is necessary for the students to be familiar with: the form and size of atoms and molecules; Avogadro's number; atomic and molecular masses; the chemical bond, with emphasis on the carbon-carbon bond; and liquid solutions and solution concentrations. For the stu...