Undergraduate chemistry students' perceptions of and misconceptions about buffers and buffer problems

Both upper-and lower-level chemistry students struggle with understanding the concept of buffers and with solving corresponding buffer problems. While it might be reasonable to expect general chemistry students to struggle with this abstract concept, it is surprising that upper-level students in analytical chemistry and biochemistry continue to struggle even though buffers are taught in many chemistry classes in an undergraduate program. Anecdotal evidence indicates that this is the case; however, little research exists to describe or explain students' difficulties with buffers. The goal of the research presented in this paper is to determine how undergraduate general chemistry, analytical chemistry, and biochemistry students perceive buffers and buffer problems. In order to examine students' experiences with buffers and buffer problems, we first interviewed students about how they understand and visualize buffer systems. We then asked the students to think aloud as they solved buffer problems and to reflect on what they do and do not understand about buffers. Here, we discuss students' ideas about buffers and how they function, the misconceptions students have about buffers and buffer problems, and the types of support students need to understand buffers and solve buffer problems.