M8B MoDRN Catalysis: Catalyst Experiment

[@felixjaneway]

I really appreciate access to these sorts of videos as I lecture chemistry myself and I'm always looking for good practice. I wonder if I can offer some useful feedback pedagogically and hope that this is not intrusive. Prof. probably felt during the demonstrations that it would have been more useful to have the pre-measured peroxide in the flasks before he began. On addition of the Iron (II) Chloride, the solution immediately changes colour dramatically, and my experience is that students would conflate that with doing something very quickly despite the point in the demonstration being that the FeCl2 is the catalyst with the slowest turnover. On this scale the colour is the most obvious observable change in the flask. As a viewer who probably is seeing more than someone in the lecture theatre would, I just had to take Prof's word that the catalysts worked in the order suggested, I couldn't really tell because of the scale of the reaction, and I wondered if it would be more effective to visualise the results more obviously. Otherwise we lose the joy of doing the demonstration in class. To some degree making a visual assessment of "fizzyness" is fine, but it seems like Prof. also had a chance to discuss how a good catalyst is measured. In this case you could have all three conical flasks bunged and tubed to three large inverted measuring cylinders of water. You take some volunteers to help you insert all three catalysts into the flasks and bung them up immediately. You have the chance to illustrate that the RATE of oxygen production is the important thing here, is it being produced quickly? How can we tell? Well we should see each cylinder fill up with oxygen at different rates. The 'best' catalyst performs more conversions of H2O2 per second and so makes more oxygen per second. BUT all three reactions will eventually produce the same amount of oxygen. You could even draw a 'finish line' on the measuring cylinders and have students time the reactions as they go.

[@EmuNext]

I love this videos, I want more.

[@AndrewBackhouse1]

cool