An Integrated Approach To Introducing Biofuels, Flash Point, and Vapor Pressure Concepts into an Introductory College Chemistry Lab

Abstract

Students explore the fundamental chemical concepts of vapor pressure and flash point in a real-world technical context, while gaining insight into the contemporary societal issue of biofuels. Lab activities were developed using a closed-cup instrument to measure the flash point of various biodiesel samples. Pre- and post-tests revealed that the student’s grasp of the relationship between vapor pressure and flash point went from 46% to 91% after completing the lab and 76% of students responded that measurement of flash point helped them better understand the concept of vapor pressure. In the 3-h lab, students produce a small sample of biodiesel fuel and then evaluate the safety and quality of their product compared with a commercially available reference fuel that meets ASTM specifications. The experiment illustrates how fuel properties depend on the production process and the resulting composition and purity of the fuel product. The observed differences in fuel flash points provide for an introduction of the concepts of chemical quality assurance and quality control. The goal of this lab is to increase understanding of biofuels and associated chemical concepts that influence the properties of various renewable and fossil fuels.