The practical activities needed in chemistry lessons. However, during the covid-19 pandemic, a suitable practical guide is needed. Therefore, a practical guide that can involve students directly in practical activities in online learning and blended learning is needed. The purpose of this study is to determine the feasibility of the Practical Guide for Determining Reaction Rate and Reaction Order Based on the Colorimeter® Application based on expert judgement and students’ response. This study employs a research and development (R&D) using 4D(Four-D) model, starting from define, design, develop, and dissemination stages. This research is limited to the develop stage due to the limited time and ability of the researcher. The subject of this study was a practical guide which was tested to 6 students in the initial trial and 20 students of Chemistry Education FKIP Untan in the main trial. Data collection tools used are the feasibility assessment sheets and students’ response questionnaires. The results of expert assessment using the Gregory test closeness model indicate a very feasible criteria with the validity value of 1.00 which in a very high level in terms of the feasibility of the content, language, and graphics. The result of the initial trial and main trial obtained an average percentage of 91% and 94% respectively with very good criteria. The results of this study imply that the practical guide developed is suitable for use in the practical activities. In addition, the practical guide has an attractive appearance and can be used in practical activities to support students’ understanding of reaction rates’ concepts.

Alternative conceptions or misconceptions is believed as the main barrier for most students who learn chemistry. Students who hold alternative conceptions will struggle to understand the advanced concepts. Therefore, identifying those alternative conceptions is important. In this study a diagnostic test was designed and developed to identify students’ alternative conceptions about intermolecular forces (IMFs). The diagnostic test developed in this study consist of 19 multiple choice questions with open reason. The test was administered to 88 university students who learn chemistry. Data collected were analyzed using SPSS. The validity and the reliability of the test were 0.526 and 0.878 respectively. The result indicates that the test is valid and reliable. The mean difficulty value and discriminatory index are 0.623 and 0.45 respectively. The findings of the item analysis showed that the test is in moderate difficulty and the discriminatory of the test is in good category. Meanwhile, the average distractor effectivity for the diagnostic test is 3 options (out of 4 options), which means the distractors are in good category and well function. Those findings indicate that the two-tier diagnostics test could be used to identify students’ alternative conceptions and understanding about IMFs.