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

Abstract

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.

Improving the Teaching/Learning Process in the Binary Vapor–Liquid Equilibrium Experiment Based on the Activity Coefficient Model

“…Vapor−liquid equilibrium (VLE) is the thermodynamic foundation of distillation processes and plays an important role in the students' understanding of phase behavior, 1,2 laboratory research, 3 and industrial operations. 4 A fundamental experiment in physical chemistry laboratories is to construct the VLE phase diagram, usually the T−x−y diagram, for a twocomponent nonideal solution system exhibiting substantial deviations from Raoult's law.…”

“…Vapor–liquid equilibrium (VLE) is the thermodynamic foundation of distillation processes and plays an important role in the students’ understanding of phase behavior, , laboratory research, and industrial operations . A fundamental experiment in physical chemistry laboratories is to construct the VLE phase diagram, usually the T–x–y diagram, for a two-component nonideal solution system exhibiting substantial deviations from Raoult’s law. , This entails gathering boiling temperature and corresponding composition data for both vapors and liquids through the use of self-designed special glass boiling bottles in experimental teaching (Figure ).…”

Creating and Experimenting with a Low-Cost, Rugged System to Visually Demonstrate the Vapor Pressure of Liquids as a Function of Temperature

“…In this context, some advances were reached regarding the dissemination of low-cost activities that promote contact between students and experimentation, either through the use of computational resources that simulate laboratory conditions and allow the student to carry out virtual experiments; − through the creation of real experiments with a lower cost apparatus; ,− or through experiments that are simpler to execute, − are miniaturized, or are environmentally friendly. , Aligned with this trend and motivated to improve students’ current understanding of liquid–vapor equilibrium − and properties of solutions, , the aim of this work was the creation of a low-cost alternative apparatus to study the vapor pressures of different liquids as functions of temperature.…”

A Simple and Fast Method for Investigating the Liquid–Vapor Equilibrium of the Water-Acetic Acid System

“…This topic has been extensively explored in the J. Chem. Edu . − and is a fundamental educational aspect for students. Therefore, it is included in the high school chemistry curriculum …”