Identifying Liquid–Gas System Misconceptions and Addressing Them Using a Laboratory Exercise on Pressure–Temperature Diagrams of a Mixed Gas Involving Liquid–Vapor Equilibrium

This study focuses on students’
understandings of a liquid–gas
system with liquid–vapor equilibrium in a closed system using
a pressure–temperature (P–T) diagram. By administrating three assessment questions concerning
the P–T diagrams of liquid–gas
systems to students at the beginning of undergraduate general chemistry
course, lack of understanding of the fundamental concepts concerning
liquid–vapor equilibria, the ideal gas law, and boiling points
was identified. A learning program for liquid–gas systems was
then designed for students at the undergraduate general chemistry
level to address this issue. It consists of a laboratory experiment
and postlaboratory exercise and is intended to provide integrated
student understanding. During the learning program, students actively
used the related concepts to explain the physical chemistry of a liquid–gas
system and integrated the concepts to explain practical systems in
their daily lives using a P–T diagram. An outline of the learning program is reported on the basis
of our educational practice.