Irma Kartika Kusumaningrum, Surjani Wonorahardjo, Yudhi Utomo, Hanumi Oktiyani Rusdi, Habiddin Habiddin, Ika Nazih Januar Fitri
Two experimental laboratory procedures for determining the distribution coefficient of analyte between two immiscible solvents have been used as teaching material in an analytical chemistry laboratory. The two teaching materials are the distribution of acetic acid between water & diethyl ether and the distribution of I2 between water and chloroform. Students were assigned to determine the analyte distribution coefficient (Kd) and the effect of analyte concentration on the Kd value. The assessment of experimental procedure performance was based on some criteria (1) visual clarity of chemical changes, (2) the level of laboratory work difficulty, (3) ability of students to determine the appropriate Kd value, (4) ability of students to explain the effect of analyte concentration on the Kd value. The initial trial of the procedure did not demonstrate the optimal expected outcome. Students struggled to experiment smoothly and precisely, implying the necessity to refine the procedure for the next purpose. For example, students failed to determine the correct Kd value and improperly explained the relationship between analyte concentration and Kd value. The students' difficulty in employing the procedure are discussed and considered to produce a valid and reliable procedure. © 2023 American Institute of Physics Inc.. All rights reserved.
Department of Chemistry, Universitas Negeri Malang, Malang, 65145, Indonesia