Page 20 - Curriculum Visions Dynamic Book

Separating carbon compounds
Organic materials, those containing carbon, are mainly very chemically complex; however, this is not always noticable.
For example, the red juice from, say,
a beetroot, may not at first sight seem complex at all.
But, just as there are ways of showing
that the simple colour of white light is in fact made of many colours of light combined, so it
is possible to show that a “simple” juice is made of an extraordinary array of chemicals, each one containing different carbon compounds.
On these pages you can see how it is done
using the process of chromatography.
Also...
The process demonstrated here
is an example of chromatography,
the use of a compound that does
not react, to separate out the
components of a complex mixture (in
this case a vegetable dye). A substance
like aluminium oxide, used in this way,
is called a stationary phase. Substances
easily attach to its surface (a process called
adsorption) and are also easily washed off again.
Each substance “sticks” to the aluminium oxide to
a different degree, so that the least firmly stuck can
be washed off most easily, and so on. As a result, the various compounds making up the original substance wash out of the base of the column one at a time, and can be collected separately.
 The beetroot is first prepared by crushing it using a pestle and mortar.
 The beetroot juice is diluted with a liquid in which it can dissolve (in this case acetone).
Crushed beetroot leaves
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