Validity of the 5C Learning Model (Connecting, Confrontation, Collaboration, Clarification, Confirmation) Based on Virtual Laboratory to Enhance Students’ Relational

This study seeks to test the validity of the 5C learning model (Connecting, Confrontation, Collaboration, Clarification, Confirmation) based on a virtual laboratory in the Physical Chemistry II lecture. The 5C learning model was developed to address the challenges of teaching abstract and complex concepts, such as reaction kinetics, which require students to possess relational understanding and deep conceptual thinking skills. This study employed a research and development approach using the ADDIE model (Analysis, Design, Development, Implementation, Evaluation), focusing on the design and development stages. Model validation was performed using the expert judgment of chemistry experts and instructional design experts, who assessed content feasibility, syntax structure, and alignment with modern learning principles. The validation results showed that the learning model possessed very high content and construct validity, with an average score above 90%. The model's validity was supported by theoretical foundations from constructivism (Bruner, Vygotsky). Piaget 's cognitive development theory and Ausubel’s theory of meaningful learning were integratively represented in the 5C model’s learning syntax. The model’s syntax was proven to be logical, systematic, and relevant to the characteristics of the Physical Chemistry II course, and it supported the achievement of graduate learning outcomes (CPL), particularly in strengthening relational understanding. Therefore, the 5C learning model based on virtual laboratory is feasible to be implemented as an innovative responsive approach to chemistry learning in the digital age. Keywords: model validity, 5C learning model, virtual laboratory, physical chemistry, relational understanding