Naslov
Kemijski sat na satu kemije
(It's time for chemistry clock!)

Autori
Šarić, Lana ; Preočanin, Tajana ; Tomišić, Vladislav

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, ostalo

Skup
2. Hrvatska konferencija o obrazovanju u kemiji

Mjesto i datum
Split, Hrvatska, 08.11.2013. - 11.11.2013

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Domaća recenzija

Ključne riječi
kemijska kinetika ; satna reakcija (clock reaction) ; učenje otkrivanjem
(kinetics ; clock reaction ; learning by discovering)

Sažetak
Chemical kinetics is a part of Chemistry which main goal is to study the rates of chemical reactions as well as conditions that influence the rate of reaction. It is often treated superficially because of the prejudices due to the fact that it is hard to understand and not so interesting for the students, also it is dull to the more theoretical approach rather than practical. Due of their visual appearance clock reactions could find their use in practical part of the high school chemistry. This particular experiment can bi well used when talking about conditions which influence the rate of reaction. Reactions in which there is a visible effect of changing colour of the complex mixture because of the sudden change of concentration of one the reactants are called clock reactions. Their basic principle is that the complex reaction mixture must content: • reactants (A and B) which form the product (P) ; • limiting agent (L) which absorbs the product so the reaction doesn't go off to soon • indicator (I) which gives the signal while reacting with the product. Reactions can be pointed out by following scheme: A + B → P P + L → C P + I → S The Landolt clock reaction, oxidation of iodide with iron(III) ions, was adapted to be preformed as a team work for high school students and available conditions in students laboratory (5 groups, 90 minutes period). Each group of students performs an experiment with solutions given concentration at three different temperatures. Results are presented in tables and graphs within each group, and the results of all groups together. From these results students should come to the conclusion how the concentration of reactants and temperature affect the rate of chemical reactions. Beside the introduction to chemical kinetics, students are introduced with a scientific approach.

Izvorni jezik
Hrvatski

Znanstvena područja
Kemija

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