Nak Han Jang (Kongju National University, Korea), Jeong Ae Won (Daejeon Education & Science Research Institute, Korea)
We have investigated Korean high school students’ and chemistry teachers’ understanding about definition and neutralization reaction for acid-base concepts. In this study we have developed the multi-dimensional analysis using a quantitative research method by questionnaire and a qualitative research method by semi-constructed interview, and the teachers’ teaching methods.
Many Korean high school students and chemistry teachers used Bronsted-Lowry acid-base definition when they classified acids or bases. Students who understood about Bronsted-Lowry acid-base definition could also use Arrhenius acid-base definition in problem solving situations. However, students who consistently use only Arrhenius definition to solve problems couldn’t understand about acid-base definitions fully and classify acids or bases properly. These difficulties should be due to no understanding the Bronsted-Lowry acid-base definition, only memorizing it. For understanding Bronsted-Lowry acid-base definition, students have to comprehend various concepts such as chemical equilibrium, dynamic equilibrium, reversible reaction, relativity of classifying acids or bases. But many textbooks wouldn’t explain relations between Bronsted-Lowry acid-base definition and these concepts explicitly. Also, chemistry teachers didn’t explain differences between Arrhenius definition and Bronsted-Lowry definition correctly.
Many Korean students understood that neutralization reaction is the formation reaction of water and salt, and such definition of neutralization reaction was attributed to textbook descriptions. But they couldn’t understand the neutralization reaction based on Bronsted-Lowry definition. Also, only 24% chemistry teachers explained the neutralization reaction based on Bronsted-Lowry definition. Many Korean teachers thought that it was necessary to teach characteristics, applicable limitations and viewpoints of each acid-base definitions exactly when they taught various acid-base definitions. Also, they thought that inaccurate descriptions about acid-base definitions and neutralization reaction would lead to students’ misconceptions about these concepts.