From the webpage, go down to Unit 12: Kinetics and Nuclear Chemistry: The Need for Speed video.
Click on the VoD block on the top right of the description of the video
This will open up a dialog box that will have the video to watch.
Sometime it does not work the first time and you will need to do it again (you have already watched one of these, Unit 4:Organizing Atoms and Electrons: The Periodic Table)