The definition of a clock reaction is a matter of dispute that remains unresolved. These clock reactions not only are beautiful but also belong to a class of nonlinear chemical phenomena including propagation of wave fronts, oscillating reactions and Turing structures, which are related to several natural processes and rhythms –. Some of these reactions have captured the attention of a many students and others due to their sudden color changes that occur after a lag time or induction period. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.įunding: This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico, grant 303988/2009-6 ( Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, E-26/110-107/2007 ( and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior ( The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist.Ī clock reaction is a special chemical phenomenon of which the Landolt clock reaction is among the best examples. Received: SeptemAccepted: NovemPublished: December 26, 2013Ĭopyright: © 2013 Sant'Anna et al. Williams, University of Melbourne, Australia Waste DisposalDispose all liquids down the drain with plenty of water.ĭig deeper into the science behind clock reactions in this paper from the Journal of Chemical Education.Citation: Sant'Anna RTP, Monteiro EV, Pereira JRT, Faria RB (2013) The Ozone-Iodine-Chlorate Clock Reaction. ![]() Be very careful not to spill any of the solution. ![]() Safety Precautionsīe careful when working with the iodine – it stains, and it stains really well. Once the Vitamin C is used up, the solution turns blue, because now the iodine element and starch are present. Now after a short time as the reactions keep proceeding in this fashion, the Vitamin C gets gradually used up. The net result, at least for part of the time is that the solution remains colorless with excess of iodide ions being present. BUT, before that can actually happen, the Vitamin C quickly reacts and consumes the elemental iodine. In Reaction # 1 iodide ions react with hydrogen peroxide to produce iodine element which is blue in the presence of starch. During these reactions two forms of iodine created – the elemental form and the ion form. There are actually two chemical reactions going on at the same time when you combine the solutions. Keep pouring the liquid back and fourth between the cups. Pour solution A into solution B, and pour the resulting solution back into the empty cup to mix them thoroughly.Prepare “solution B” by adding 2 oz of water to 3 tsp of hydrogen peroxide and 1/2 tsp of liquid starch solution.Combine 1 tsp of the vitamin C stock solution with 1 tsp of iodine and 2 oz of water.Label this as “vitamin C stock solution”. Make a vitamin C solution by crushing a 1000 mg vitamin C tablet and dissolving it in 2 oz of water.distilled water (tap water will work OK as well).This version of the classic “iodine clock reaction” uses safe household chemicals most people have on hand at home. There are actually a couple of simple chemical reactions going on at the same time to make this “clock reaction” occur. Two colorless liquids are mixed together and after a few moments the mixture turns a dark blue color. In may ways this experiment feels almost like magic. Try an at home version of this experiment using a few things you may have in your bathroom medicine cabinet. ![]() KeyBank Discovery Theater Special Features.
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