As a result of winning a Roentgenium Award in the Cambridge Chemistry Challenge 2016 - a written examination comprising of some tough and challenging chemically related questions - I was invited to attend the University of Cambridge for a residential chemistry course on September 2nd to 5th - 4 days of chemical fun were in the offing! As a matter of interest, Roentgenium (the metal from which my medal is made) is a chemical element that has an atomic number of 111 and located in group 11 - the 'precious metal' group - other members of this group being the better known copper, silver and gold.
After I arrived at St. Catharine’s College, Cambridge, on the afternoon of September 2nd 2016, 28 students and I were fortunate to have dinner with Tim Hersey, Dr Peter Wothers, Dr Ben Pilgrim and some students based in the college. Tim Hersey introduced us to the university and the course on offer for potential study. We shared a wonderful evening together talking chemistry with Cambridge teachers and students.
On the 3rd morning, we went to the main Chemistry Department of the University. Dr Ben Pilgrim and Dr Peter Wothers taught us some further organic synthesis using some interesting ideas of levels of functional groups, where each level is based on oxidation number. After one identifies the oxidation level of a particular functional group, the mechanism of synthesis can be determined. For example, if the level goes up it might be an oxidation; if the level keeps same it might be hydrolysis, and so on. We tried to work out synthetic routes resulting in the formation of some medicinal compounds which was very interesting, and afterwards Dr Kathryn Scott from the University of Oxford discussed with us whether it is possible to make EDTA whilst being airborne in an aircraft. EDTA is used a potential antidote for arsenic poisoning - a situation that has created considerable popular interest in a recent story line on TV's 'Torchwood'. The answer, apparently, is definitely no. Although the required reactant, 1,2-diaminoethane, can be found within an aircraft (not sure from where though), the reactions require extreme conditions. For example, it is impossible to produce methanoic acid from methanol in a bottle with a silver catalyst because it requires a temperature of 600°C - not an easy feat whilst being airborne.
In the afternoon, we moved into a laboratory, lab coat and goggles at the ready. Our challenge was to deduce the nature of an unknown inorganic copper complex using several titrations. I was surprised as this practical appeared in the 2009 International Chemistry Olympiad as a question (and also featured in a question in round 1 of the chemistry Olympiad 2010). It was exciting to do a very complex experiment that featured in an exam question. This experiment was well designed and thought through - the climatic scene being that the end point of the titration was marked by a colour change from “Cambridge Blue” to “Oxford Blue”!
The following day, Dr Wothers taught about some atomic orbital theory and we probed deeply into what proved to be a highly complicated area. Using the famous Schrödinger Wave Equation, the wave function of a particular orbital can be determined. I found it is easier to visualise the shapes of orbitals by looking at the mathematical functions that represented them. For example, the 2s orbital is like a small sphere in a larger sphere, and there is a wave-node between them that has zero probability of electron existence.
In the afternoon, we were expected to determine the critical micelle concentration of a surfactant called sodium n-dodecyl sulfate (actually it is just soap). We were provided with a conductivity meter and related apparatus, but no hints at all, as to how to solve the problem. The solution to the problem involved adding a particular volume of known concentration of SDS solution by burette, and measuring the conductivity of the solution, and to repeat this several times. By sketching a graph of conductivity against concentration, it is possible to find a turning point at which the gradient becomes smaller. I found it hard to design an experiment on my own, but felt that I had achieved something special when I had completed the task, as it was all my own work.
Dr Ben Pilgrim gave a presentation in the evening involving setting fire to several balloons containing hydrogen; this took place in the Corpus Christi College grounds. To show the huge amount of stored potential energy stored in hydrogen gas, he ignited two balloon containing mixtures of hydrogen and oxygen. Each balloon gave an extremely loud explosion, much louder compared to when one ignites a hydrogen gas balloon without any pre-mixed oxygen. He also showed us a D2O ice cube - D2O is a special form of water in which all hydrogen atoms are replaced by the heavier hydrogen isotope called deuterium. As the hydrogen atom in this form is heavier than ordinary 1-hydrogen, the ice cube actually sinks in water! After this presentation, we had a dinner at Corpus Christi College and visited both inside and outside of the college.
Attending this course was a stimulating and highly interesting experience for me. It also provided a brief impression of what chemistry at university level was like (tough!), and scientific research taking place. I found the chemistry I did highly challenging, but this is this challenging nature that attracts me to such a wonderful subject.
Report by winner Jiwang Chen, E Social, 6.2