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The Briggs-Rauscher Reaction as a Model of a Chemical Clock

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To initiate a Briggs-Rauscher reaction, first make up three solutions. Solution A contains hydrogen peroxide. B is a solution of potassium iodate and perchlorid acid. Solution C contains malonic acid, manganes sulphate and soluble starch.
As soon as the reactants mix, the chemical reaction begins. The colourless solution turns golden brown; then it changes to deep blue - and indication of the formation of a starch -iodine complex. In the further course of the reaction, the blue colour disappears, the solution becomes colourless, and the cycle is repeated again. During the reaction, individual reactants are used up; bubbles of gas are produced: CO 2 is released. The concentrations of the reactants change periodically.
When the experiment is repeated speeded up eight times, the oscillations are more clearly apparent.
Towards the end, the reaction velocity decreases. Finally, the solution remains blue.
The third experiment at doubled speed. The oscillations are due to autocatalytic reactions. The intermediate compounds produced periodically change their state of oxidation. Iodine is alternately produced and used up. The periodical occurrence of a substance - for example, the liberation of iodine - determines the time pulse of the oscillation. This forms base of our chemical clock.
Reisstärke
Iod
Chemische Reaktion
Härteprüfung
Reaktionsführung
Oxidschicht
Komplexbildungsreaktion
Setzen <Verfahrenstechnik>
Bukett <Wein>
Konzentrat
Base
Chemische Verbindungen
Lösung
Computeranimation
Teststreifen
Thermoformen
Säure
Wasserstoffperoxid
Kaliumiodat
Oszillierende Reaktion
Permanganate
Periodate

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Formale Metadaten

Titel The Briggs-Rauscher Reaction as a Model of a Chemical Clock
Alternativer Titel Die Briggs-Rauscher-Reaktion als Modell einer chemischen Uhr
Autor Hock, Bertold
Bolze, Alfred
Mitwirkende Trude Hard (Redaktion)
Horst Wittmann (Kamera und Schnitt)
Lizenz CC-Namensnennung - keine kommerzielle Nutzung - keine Bearbeitung 3.0 Deutschland:
Sie dürfen das Werk bzw. den Inhalt in unveränderter Form zu jedem legalen und nicht-kommerziellen Zweck nutzen, vervielfältigen, verbreiten und öffentlich zugänglich machen, sofern Sie den Namen des Autors/Rechteinhabers in der von ihm festgelegten Weise nennen.
DOI 10.3203/IWF/C-1495eng
IWF-Signatur C 1495
Herausgeber IWF (Göttingen)
Erscheinungsjahr 1983
Sprache Englisch
Produzent IWF
Produktionsjahr 1980

Technische Metadaten

IWF-Filmdaten Film, 16 mm, LT, 45 m ; F, 4 min

Inhaltliche Metadaten

Fachgebiet Chemie
Abstract Chemical oscillation reactions are made visible by the periodic appearance and disappearance of an iodine-starch complex. The oscillation is based on autocatalytic reactions, in which intermediary compounds are oxidized and reduced in rhythmic sequence. The total reaction is driven by the decarboxylation of malonic acid. With time-lapse.
Schlagwörter Briggs-Rauscher reaction
chemical clock
model reaction
oscillation reaction
synergetics
cell biology

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