C3 - Chemical Detection

forensic science, qualitative, quantitative.

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Analysing Substances...

Chemical analysis is used for such things as forensic scientists that investigating substances or objects that were at a crime scene. An example of this is checking the alcohol content of a driver's blood that had been in a crash to use in court as evidence.

QUALITATIVE - description of something, tells you what's present (colour)

QUANTITATIVE - mesaurable property, tells you how much is present (mass)

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Tests for Positive Ions

If you have a compound, but do not know what is it, the way to identify it is through a test...

Flames Tests
Compounds of some metals give colour when heated, this is a flame test
Sodium - orange/yellow flame
Potassium - lilac flame
Calcium - brick red flame
Copper - blue/green flame

Addition of Sodium Hydroxide
By adding a few drops of sodium hydroxide, this is another test for positive ions.
Calcium - White
Copper (II) - Blue
Iron (II) - Sludgy green
Iron (III) Red/brown
Aluminium - White at first, then redissolves to form a colourless soloution

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