We describe a case study involving the preparation of an extensive set of online videos to web-enhance a campus-based introductory chemistry class. Student performance and perceptions were compared for two groups: an experimental group, who could freely access the videos during the semester, and a control group, who did not have access to the videos. No statistically significant difference in performance was observed on a common final exam for these two groups. Students in the control group gave statistically significantly higher ratings for "overall quality of instruction" and "workload; amount of effort/work" on the end-of semester formal course evaluations. Qualitative sentiment analysis revealed more positive sentiment than neutral or negative sentiment in the free response comments of both groups. Implications of differences in student perception and valuation of instructor effort in traditional live lectures versus courses that employ pre-recorded lecture videos are discussed.