Students’ difficulties with chemical reaction types

Abstract

The initial problem that prompted this study was students’ difficulties with chemical reaction types (CRT). In diagnostic tests in South Africa, across some of the major universities, CRT reflected as the poorest score of the basic and special topics in chemistry. Questionnaire results from both South Africa and Norway also reflected the inability of students and teachers to classify chemical reaction types and underlined the misconceptions about important CRT principles. The aim of this study was twofold: (1) to investigate why students struggle with chemical reaction types and the extent to which textbook related problems and teacher induced problems play a role, and (2) how practical work can be used as an intervention to address CRT misconceptions. To achieve the first part of the aim, a review of 102 general chemistry textbooks on CRT was conducted. In the review, numerous CRT and inconsistent and problematic chemical reaction type terminology were identified. To achieve the second part of the aim, documented international misconceptions on CRT were collected and these misconceptions were used to teach for conceptual change with the aid of the MYLAB small scale chemistry (SSC) kits as an intervention tool. The results of the textbook study showed no progression towards a standard in CRT classification over the years from 1661 to 2017 (year of textbook publication). Furthermore, confusing and ambiguous CRT terms are used in textbooks. Consequently, a new theoretical framework (fig.1, paper 1) and a theoretical framework model (TFM, fig.2, paper 1) were proposed to simplify and clarify the classification principles of CRT and CRT terminology. The TFM is supported by the analysis on the listed CRT and the complete chapter content analysis of the CRT chapters in the textbooks. The outcomes of the textbook investigations recommend a standard classification system and standardized terminology for CRT to assist students to understand and master a complex chemistry concept and led to the proposal of such a classification system. The aim of the practical intervention was to attempt to reduce misconceptions in CRT by doingpractical work, using structured and open worksheets, to enhance learners’ understanding of theoretical work. Much of a teacher’s time is taken up with identifying and correcting misconceptions during students’ journey to a more complete understanding of concepts and construction of knowledge in chemistry. The SSC kit proved to be a useful tool in the intervention of teaching for conceptual change. A number of conceptual change models were successfully implemented, using the kit and the worksheets. Metacognition especially was addressed effectively, leading students to identify the incorrect concept, the correct scientific concept, the possible origin of the concept and also strategies for conceptual change. The metacognition activity highlighted the students’ superficial knowledge of CRT and their inability to propose strategies for teaching for conceptual change. They often know what they must do, but not how to do it. More practice and skills training needs to take place. Thus, our basic hypothesis, that misconceptions about chemical reaction types are symptomatic of textbook related problems and problems with other related chemistry concepts, is true and SSC kits can successfully be used as intervention tools to address these misconceptions.