Tests for Ions - Unit 1 Topic 9 Flashcards
What is a salt?
Compound consisting of at least 2 ions (cation & anion)
What is a flame test?
When a sample of salt is held, using nichrome wire, in a hot Bunsen flame, it gives characteristic flame colour
Flame test colours: Sodium Potassium Barium Calcium Copper
Yellow Lilac Apple green Brick red Blue/green
What is a precipitate?
An insoluble substance which sometimes forms when 2 aqueous solutions are mixed
Precipitate colours & whether they redissolve in excess (cations using NaOH) Magnesium chloride Aluminium chloride Zinc (II) chloride Copper (II) chloride Iron (II) chloride Iron (III) chloride
White - No White - Yes White - Yes Blue - No Green - No Red/Brown - No
What do metals ions produce in terms of precipitates?
Gelatinous precipitate
Precipitate colours (halides with nitric acid)
Sodium chloride
Potassium bromide
Sodium iodide
White
Cream
Yellow
Precipitate colours (sulfates with barium chloride)
Aluminium sulfate
Magnesium chloride
Sodium sulfate
White
None
White
How do you test for carbonate ions?
Bubble compound through limewater
How do you test for the presence of cations?
Flame test (nichrome wire)
How do you test to identify cations?
Dissolve salt in water & add Sodium hydroxide.
How do you test for halide ions?
Dissolve solid in water, add nitric acid & silver nitrate
How do you test for sulfate ions?
Dissolve salt in water & add barium chloride
