Friday 2 November 2018

Breaking up a molecule - chemical reactions

It is pretty complicated to break up an atom and the result is a nuclear reaction. But molecules are broken all the time. Today we split a molecule. This is called decomposition. We had hydrogen peroxide and separated it into water and oxygen. We used a catalyst to cause a chemical reaction to break them apart. The catalyst was potassium permanganate. We explored what both chemicals are and what they are used for.

Hydrogen peroxide (H2O2) - is a naturally occurring substance that can be found in every living thing (including people) as well as in things like snow, rain, lakes, and rivers. We use it for all sorts of things such as bleaching our hair and as a disinfectant.

Potassium permanganate (KMnO4)- is a substance created by scientists. It is used for things such as preserving fruit and treating water.



The reaction was quite spectacular. Because of the heat generated the water escaped in its gas form - steam.

We did a second experiment where we added detergent and water to the same reaction. The detergent trapped the steam and oxygen as it escaped creating lots of bubbles that looked like 'elephants toothpaste'.

We have looked at what a chemical reaction is. A chemical reaction is one where you end up with a new element or molecule. It is usually irreversible. There are clues to help you work out if it is a chemical reaction. These experiments today were chemical reactions. We saw changes in temperature, sound, colour and saw bubbles sizzling away. All clues of a chemical reaction.
There was quite a lot of heat generated (one feature of some chemical reactions). When heat is generated it is called an exothermic reaction.

Here is a video of the reaction as well as some other 'bigger' examples.

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