Treating the Avogadro Constant as a Unity-Dimensional Conversion Factor

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 12 Issue 4 (2007) pp 236-239

Treating the Avogadro Constant as a Unity-Dimensional Conversion Factor

Fred Watson

Chemistry Department, University of Louisiana at Monroe, Monroe, LA 71209, watson@ulm.edu
Received July 15, 2006. Accepted January 11, 2007.

Published online: 4 August 2007

Abstract. University students of introductory general chemistry can be perplexed when they are introduced to the dimensioned quantity, the Avogadro constant (N_A = N_A mol^–1). They may be awed by the enormity of its numerical part (Avogadro’s number) and confused by its numerator-less units (mol^–1). To ease students’ discomfort in dealing with this quantity, it is recommended that general chemistry lectures not stress the enormity of N_A and simplify the units by expressing a numerator (things/mol). It is further recommended that N_A be interpreted as unity. Lecture notes are presented that demonstrate the unity-factor interpretation, followed by questions designed to affirm students’ understanding of the mole concept.

Key Words: In the Classroom; physical chemistry; kinetics

(*) Corresponding author. (E-mail: watson@ulm.edu)

Article in PDF format (84 KB) HTML format page numbers updated 9/15/07