| 词条 | Chemical clock |
| 释义 |
A chemical clock (or clock reaction) is a complex mixture of reacting chemical compounds in which the onset of an observable property occurs after a predictable induction time.[1] In cases where one of the reagents has a visible color, crossing a concentration threshold can lead to an abrupt color change after a reproducible time lapse. One class of example is the iodine clock reactions, in which an iodine species is mixed with redox reagents in the presence of starch. After a delay, a dark blue color suddenly appears due to the formation of a triiodide-starch complex. Additional reagents can be added to some chemical clocks to build a chemical oscillator. For example, the Briggs-Rauscher reaction is derived from an iodine clock reaction by adding perchloric acid, malonic acid and manganese sulfate.[2]. References1. ^{{Cite journal| doi = 10.1021/ed079p40| volume = 79| issue = 1| pages = 40A| last = Wright| first = Stephen W.| title = Tick Tock, a Vitamin C Clock| journal = Journal of Chemical Education| accessdate =| date = 2002-01-01}} {{DEFAULTSORT:Chemical Clock}}2. ^{{Cite journal|last=Briggs|first=Thomas S.|last2=Rauscher|first2=Warren C.|date=1973-07-01|title=An oscillating iodine clock|url=https://doi.org/10.1021/ed050p496|journal=Journal of Chemical Education|volume=50|issue=7|pages=496|doi=10.1021/ed050p496|issn=0021-9584|bibcode=1973JChEd..50..496B}} 6 : Chemical kinetics|Clocks|Non-equilibrium thermodynamics|Oscillation|Analytical chemistry|Articles containing video clips |
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