An Analysis of Student Performance on Acid-Base Equilibria Problems Before and After Instruction
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Publisher:The Ohio State University
Series/Report no.:The Ohio State University. Department of Chemistry and Biochemistry Honors Theses; 2020
Solving quantitative problems is an important feature of most undergraduate chemistry courses. Students frequently struggle with these complex quantitative problems because they require mathematical skills, conceptual understanding, and problem-solving strategies. The topic of acid-base equilibria includes quantitative problems that are difficult for many students in General Chemistry, and this same topic is also an important part of upper-level Analytical Chemistry courses. General Chemistry students are novices when they first encounter this topic, and students that complete Analytical Chemistry can be considered undergraduate experts. This investigation aimed to understand how novice and expert students solve acid-base equilibria problems and identify their problem-solving strategies, the heuristics they use, and any essential skills that they demonstrate. Two open-response instruments were written to elicit student problem-solving for questions involving strong electrolytes, weak electrolytes, neutralization reactions, and titrations. The study design included testing before and after instruction for General Chemistry students (n=169) and Analytical Chemistry students (n=34), and class experiences characterized for both courses in terms of lecture, homework, and laboratory activities. The open-response data were analyzed using a qualitative approach to characterize conceptual understanding, problem-solving strategies, and errors. In general, successful problem-solving strategies were the same for both novices and experts, including the application of prior knowledge and essential skills to identify the problem concept and execute the correct problem strategy. On the other hand, greater variability was found for the errors exhibited by unsuccessful novice and expert students. The analysis suggests algorithmic heuristics are commonplace, frequently without a deeper conceptual understanding.
Academic Major: Chemistry