P88: Analyzing upper-level undergraduate biochemistry students’ conceptual understanding of acid-base chemistry using different visual representations of titration curves

Author: Jon Stoltzfus, Michigan State University, USA

Co-Author: Julie Libarkin, Michigan State University, USA; Thomas Kim, Rochester Institute of Technology, USA

Date: 8/3/14

Time: 4:00 PM4:20 PM

Room: LTT 103

Related Symposium: S13

The impact of pH on the protonation state and charge of specific functional groups is important for many aspects of protein structure and function. To understand how the protonation state and charge of functional groups in proteins changes with variations in pH, students must understand what is happening to the hydrogen ion concentration of the solution during a titration and why this is occurring. We observed that visual representations of titration curves in biochemistry textbooks typically focus on the buffering region of the titration curve while visual representations of titration curves from general chemistry textbooks typically focus on the equivalence point. This study explores the effects of different visual representations of titration curves on student conceptual understanding of what happens during titration. We hypothesized that differences in the visual representation of the titration curve would influence student explanation of what was happening at different points on the titration curve. This study tests this hypothesis using surveys administered to students in their second semester of a two-semester upper-level biochemistry course. An exploratory grounded approach is used to analyze students’ constructed responses to survey items. We present data from this study and discuss implications for use of different visual representations of titration curves when teaching topics related to acid-base chemistry.