Conceptions and troublesome knowledge on acid-base using the two-tier multiple-choice diagnostic test

Abstract

Abstract Acid-base is one of the materials that tend to be difficult for students to understand. Acid-base is a material that is conceptually solid and requires an integrated understanding of many of the concepts of introductory chemistry. This research is descriptive research that aims to find conceptions of students on acid-base subjects and asking about concepts that are considered troublesome according to their learning experiences. The subjects of this research were 31 students of class XI IPA 4 at SMAN 3 Pariaman. The instruments in this research are diagnostic tests and interviews. The result of this research is the students of SMAN 3 Pariaman have difficulties in learning about the acid-base subject with high category. The percentage of conceptions experienced by students in each indicator is 56.3% of students understand the concept, 20.8% misconception, and 22.9% do not understand the concept. In the second indicator, 45.2% of students understood the concept, 18.3% had misconceptions and 36.5% did not understand the concept. In the 3rd indicator, 35.5% of students understood the concept, 31.2% had misconceptions and 33.3% did not understand the concept. In the 4th indicator, 21.9% of students understand the concept, 27.7% do not understand the concept and 50.3% do not understand the concept. Meanwhile, the acid-base theory, the calculation of pH or pOH, and the relationship between the degree of acidity (pH) and the degree of ionization (a), and the acid equilibrium constant (Ka) or the base equilibrium constant (Kb) are considered troublesome knowledge because they can be conceptually difficult.