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IGCSE Chemistry (b) Elements, Compounds and Mixtures - Coggle Diagram
IGCSE Chemistry (b) Elements, Compounds and Mixtures
1.8 Elements consist of
one type
of atom
only
Elements consist of
one type
of atom
only
Compounds are chemically bonded
A compound is a substance that is made of 2 or more different elements which are bonded together
It's very difficult to seperate the two original elements out again
Mixtures are easily seperated
Theres no chemical bond between the different parts of a mixture
The parts can be seperated by physical methods such as distillation
1.9 A mixture isnt a pure substance
Every pure substance has a specific, sharp melting point and boiling point
When a mixture is not pure it will melt or boil gradually over a range of temperatures
Physical Seperation Methods
Filtration
is used to seperate an insoluable solid from a liquid
Crystallisation
seperates a soluable solid from a solution
Seperating Mixtures - Chromatography
Paper Chromatography
It's used to
seperate out dyes
- inks, paints, food colourings etc.
Always draw the baseline with a pencil as
pencil marks are insoluable
so won't dissolve in the solvent
The end result is a pattern of spots called a
chromatogram
How it works
Different dyes will move up the paper at different rates
Some will stick to the paper and others will dissolve more readily in the solvent and travel quickly
You can calculate the Rf Value for each Chemical
An Rf Value is the ratio between the ratio of the solute's distance travelled to the solvent's distance travelled
Distillation is used to seperate mixtures that contain liquids
Simple Distillation is used to seperate out
solutions
Fractional Distillation is used to seperate out
a mixture of liquids