The limited use of teaching materials during the Covid-19 pandemic caused the authors to be interested in conducting research on the development of electronic-based teaching materials that can be used anytime and anywhere and equipped with a learning model suggested by the curriculum. The purpose of this research is to determine the validity and practicality of the guided discovery based chemical equilibrium factor e-module. The development of e-modules uses a type of 4-D development research which consists of the initial investigation, stagethe prototype making stage, and the assessment stage. The subjects of the research were three chemistry lecturers at Padang State University, two chemistry subject teachers, and sixteen grade eleven students at SMA Negeri 1 Airpura. The research was conducted in the environment of SMA Negeri 1 Airpura in April 2021. The assessment instrument used was a validity questionnaire and a practicality questionnaire. The data from the validity and practicality questionnaires were processed using data analysis techniques according to the kappa moment formula. The e-module validity value was obtained at 0.86 and the emodule practicality value was 0.89. Thus, it can be concluded that the e-module being developed has very high validity and practicality

Keywords : E-Module, Chemical Equilibrium Factor, Guided Discovery Learning, 4-D Development Model.