Developing and evaluating a multiple-choice knowledge test about Bronsted-Lowry acid-base reactions for upper secondary school students

For centuries, chemists have researched acid-base reactions and developing numerous different acid-base concepts. Consequentially, it is difficult to teach about acid-base reactions in a clear and conceptually coherent manner. We aim at contributing to teaching about acid-base chemistry by an intervention introducing upper secondary school chemistry students to an acid-base concept that is scientifically appropriate and learner-centred. This modernized version of the Bronsted-Lowry acid-base concept appears sufficiently complex for the target group. Additionally, it emphasizes the donor-acceptor concept and the reaction mechanism. In order to evaluate the gain in declarative knowledge during our intervention, we developed and piloted a multiple-choice knowledge test with Austrian upper secondary students (N = 136). By estimating a Rasch model (WLE-Rel. = 0.63, Infit(min) = 0.90, Infit(max) = 1.02, Outfit(min) = 0.89, Outfit(max) = 1.00, d = -0.44-1.8), we constructed a pre-test (11 MC items, 6 open-ended questions) and a post-test (11 MC items, 6 open-ended questions) based on key concepts of the topic for our intervention study (N = 57). Overall, the test proved a reliable tool to estimate learners' declarative knowledge about acid-base reactions in the course of the intervention study, showing a significant knowledge increase.