This study is a define phase of 4D model used in Research and Development (R&D) that aims to explore initial concept of grade XI students on acid-base topic before studying the material. Instrument used in this study was a two-tiered diagnostic test in the form of multiple-choice questions with choice of reasons that consisted of 16 items. The test was given to 100 grade XI students from various schools in West Sumatra. Students� answers were processed by grouping them into 3 categories: understand, have misconceptions and do not understand. Data were then analyzed descriptively by calculating the percentage of students' learning difficulties in all of competency achievement indicators that had been compiled. The results showed that students had difficulty in understanding some concepts of acid base such as acid base theory of Arrhenius (75.2%), of Bronsted-Lowry (81.43%), and of Lewis (100%); pH (94.04%); and acid base ionization constant (97.33%). Results of this research are then used as a consideration in the development of acid-base module designed for grade XI Senior High School learning.

This research aims to produce learning materials of module based on REACT (Relating, Experiencing, Applying, Cooperating, Transferring) for acid-base topic which content and construct are valid. The designed module graded by panellist as Subject Matter Experts (SMEs) which consists of lecturer from chemistry departement of FMIPA UNP and chemistry teachers in high school. To collect data, content validity and construct validity questionnaire were used as the instruments. The data analysis technique used in this research were Content Validity Ratio (CVR) and kappa Cohen formula. For content validity, there were three items graded by the panellists which is the suitability of module content with REACT syntax, with critical thinking sub-indicator and with chemistry scientific knowledge. Furthermore, for construct validity there were four items graded by the panellist which are contents, language, presentation, and graphic component. The Content Validity Index (CVI) were 0.903, which obtained from analysis data result of content validity. In the other side, for construct validity, the average of kappa moment was 0.924 which categorized as very high.

One effort that can be done to prepare SMA/MA students in entering the world of work is equipping them with the entrepreneurship skills, namely by integrating entrepreneurship into chemistry subjects through teaching materials in the form of modules. This study aims to reveal the level of validity and practicality of a CEP-oriented colloidal system module developed for class XI SMA/MA. The type of research used is Research and Development with 4-D model (define, design, develop, and disseminate). The research instrument used was a questionnaire in the form of validity and practicality sheet. This module was validated by 3 UNP chemistry lectures and 2 chemistry teachers of SMAN 12 Padang. Practicality test were conducted on 2 chemistry teachers and 30 eleventh grade students of SMAN 12 Padang. Data was analyzed by Cohen’s Kappa Formula. The results of the validity test showed that the module has a very high validity category (κ= 0.86). Practicality test results by teachers and students showed that the module has very high practicality category (κ= 0.82 and 0.83). Based on the results of this research, it can be concluded that the module developed was valid, practical

This study analyzed the understanding of first-year students on the concept of chemical equilibrium. It involved 30 first-year students in the faculty of mathematics and natural sciences of Universitas Negeri Padang. The students’ understanding was explored using a conceptual test. The result shows that generally, students have misconceptions about the concept of chemical equilibrium especially when the reaction reaches equilibrium as reported by many studies. The results of this study have implications for the lecturers in planning the general chemistry learning process, especially on the chemical equilibrium topic.

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