Available online
Description
A method of studying fast reactions, flash photolysis, is examined using the combination of methyl radicals as an example.
A method of studying fast reactions, flash photolysis, is examined using the combination of methyl radicals as an example.
| Module code and title: | ST294, Principles of chemical processes |
|---|---|
| Item code: | ST294; 13 |
| First transmission date: | 16-08-1975 |
| Published: | 1975 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:24:23 |
| + Show more... | |
| Producer: | Andrew Millington |
| Contributors: | Charles Harding; David Roberts; John Simons |
| Publisher: | BBC Open University |
| Keyword(s): | Azomethane; Fast reactions; Flash of light; Flash photolysis; Methyl radicals; Oscilloscope; Photodecomposition; Ultraviolet light; University of Birmingham |
| Footage description: | Harding introduces the programme with a brief experiment which demonstrates a fast reaction. He combines oxygen with nitric oxide. David Roberts explains why combinations of methyl radicals are fast reactions. He then lists two criteria which an experiment to monitor fast reactions must meet. Harding mixes two solutions as another example. He explains why mixing is too slow a method for an experiment in measuring reaction rates and concentrations. Harding next demonstrates the use of light to start and monitor a reaction. For demonstration purposes the reaction is a slow one. He goes on to explain how this technique can be modified for use in monitoring fast reactions. Harding continues to explain the technique of flash photolysis for monitoring rates and concentrations of radical reactions in more detail. David Roberts uses a diagram of a flash photolysis apparatus to explain the set up in detail. John Simons, Birmingham University, with photolysis apparatus, discusses the optics of the experiment. He points out the individual parts of the apparatus and explains the function of each. Simons goes on to discuss the electronics of the apparatus, pointing out individual parts as he goes along. David Roberts explains the function of the two monochromates used in the experiment. He uses the apparatus diagram as visual aid. John Simons prepares the apparatus. He explains what he is doing as he goes along and performs a dummy run. The results are shown on the oscilloscope. David Roberts introduces the experiment for monitoring the combination of methyl radicals. He explains why the spectrum was monitored at 2l6nm and why azomethane was chosen as the best substrate for the experiment. John Simons sets up and then carries out a flash photolysis run on azomethane combination. The results are shown on the oscilloscope. David Roberts shows the results of an experiment which used white rather than monochromatic light as in the above experiment. Roberts sums up. |
| Master spool number: | 6HT/71606 |
| Production number: | 00525_1165 |
| Videofinder number: | 753 |
| Available to public: | no |
