Most chemical reactions proceed via a reactive intermediary state of which the concentration increases to a maximum and drops to zero during the course of the reaction.
Interestingly, a few reactions have been studied that do not share this common behaviour but rather have oscillating concentrations of the intermediates.
For example, in the 1950’s the Russian chemists Belousov and Zhabotinski discovered and studied a reaction which currently is known as the reaction between the bromate cation and malonic acid which, catalyzed by a cerium (III-IV) redox couple, are transformed into bromomalonic acid and carbondioxide.
Adding a ferroin indicator to the reaction medium will visualize a remarkable phenomenon; through a complex feedback reaction characterized by accumulation and induction, the colour of the solution will strikingly oscillate from blue to red and back.
Another oscillating chemical reaction is the Briggs-Rauscher reaction, which also has fairly non-complex starting materials and will proceed in a wide range of initial conditions.
Given the spectacular nature, using these types of reactions in a classroom demonstration is guaranteed to stir interest into future scientists!
Roel Decadt
Spectacular indeed! Though the subject does not seem to be the most accessible of subjects -having in mind a very broad audience-, your entry is built up rather nicely. Meaning that all necessary elements to understand your topic are present. Well-done!
BeantwoordenVerwijderenAlso, I want to add, there is a nice, overall flow from start to finish. The attention is drawn by the title and after a simple start we -the readers- are off on a wild scientific journey. Momentum is gained and we do not stop until the last sentence which, I must say, I agree with wholeheartedly.
Interesting topic and nicely written: what more could one ask?
Kudos!
(Samuël Delefortrie)
Most chemical reactions proceed via a reactive intermediary state of which the concentration increases to a maximum and drops to zero during the course of the reaction.
BeantwoordenVerwijderenInterestingly, a few reactions have been studied that do not share this common behaviour but rather have oscillating concentrations of the intermediates.
For example, in the 1950’s [1950s] the Russian chemists Belousov and Zhabotinski discovered and studied a reaction which currently is known as the reaction between the bromate cation and malonic acid which, catalyzed by a cerium (III-IV) redox couple, are transformed into bromomalonic acid and carbondioxide.
Adding a ferroin indicator to the reaction medium will visualize a remarkable phenomenon; through a complex feedback reaction characterized by accumulation and induction, the colour of the solution will strikingly oscillate from blue to red and back.
Another oscillating chemical reaction is the Briggs-Rauscher reaction, which also has fairly non-complex starting materials and will proceed in a wide range of initial conditions.
Given the spectacular nature, using these types of reactions in a classroom demonstration is guaranteed to stir interest into future scientists!
Wow, chemistry! ;-) Good flow, good style, good English. Guess what: it's a good blog.
olaf