Learning thermochemistry: Understanding the challenges and promoting its success

This study was conducted to investigate how students approach the learning of thermochemistry, what the challenges are and how instruction can make learning of thermochemistry more accessible. Specifically, this study seeks to understand: 1) which topics in thermochemistry are more difficult to learn and which topics are easier; 2) why the difficult topics are problematic for student learning; and 3) what effect chemistry-related epistemological beliefs have on conceptual understanding of thermochemistry.;Nine high school students, ages 15 to 17, enrolled in a six-week chemistry enrichment course, participated in the study. Semi-structured clinical interviews, each of which was 15 to 40 minutes, were used to probe students' understanding. The students were interviewed either three or four times over the six-week period. Analysis of the interview data involved the identification and categorization of facets and microgenetic analysis of students' explanations.;Results indicate that the topics that were relatively easy to learn at the high school level include temperature, energy transfer for physical changes, tactile thermal sensation, heat of combustion and thermodynamic laws. In contrast, students have problems learning about heat, heat capacity, bond energy, q=mcΔT and the energetics of solution reactions.;More in-depth analysis revealed that the problematic topics are challenging for a variety of reasons. One, learning a thermochemistry topic may be troublesome if a strongly distracting alternative conception is present. Two, hidden assumptions of instructors may remain unarticulated to students. Three, students may have alternative but valid perspectives that are unknown to instructors. Lastly, information that is relevant to understanding a topic is omitted from instruction which can cause confusion. Reformulations for instruction are suggested.;In order to understand the effect of epistemological beliefs on conceptual understanding, case studies of two students were conducted. Results show that a student who believes chemistry is an integrated system of knowledge is more likely to engage in sense-making and develop deep conceptual understanding. However, a student who views chemistry to be a collection of individual facts, laws and equations is more likely to engage in rule-based reasoning, and will more likely develop alternative conceptions and misaccommodate instructed knowledge.