An active-learning concurrent preparatory general chemistry course was adopted to replace a prerequisite course that lacked effectiveness in improving student outcomes. Our previous study showed that the concurrent course increased final exam performance and retention in a cohort of students. This paper studies the course modality impact of the concurrent preparatory course on student learning and retention. Three modes of instruction (in-person, online synchronous, and asynchronous) were offered for the concurrent preparatory general chemistry course. Significant differences were found in success on the final exam and retention for the first quarter of college-level general chemistry between in-person and online students. While students in the synchronous and asynchronous modalities performed differently in the concurrent preparatory general chemistry course, there were no significant differences in the final exam performance in the main general chemistry course or retention overall.