Chemical "reef" experiment or Growing a chemical "reef" using diffusion

It is a interesting science experiment based on the phenomenon diffusion. Three different salt dissolve in water and their ions intermix to form new colored salts, the combination resembles a chemical reef.

Chemical reef

 

Reagents and equipment

• Glass container
• 100 ml distilled water 
• 2 g copper(II) sulfate.
• 2 g potassium hexacyanoferrate(II)
• 2 g ammonium iron(III) sulfate

Procedure

•  Pour 100 ml distilled water into a glass container.
• Add 2 g copper(II) sulfate, 2 g potassium hexacyanoferrate(II) and 2 g ammonium iron(III) sulfate
•  After sometime, colorful precipitates resembling reef will produce.

Process

In water,  2 g copper(II) sulfate, 2 g potassium hexacyanoferrate(II) and 2 g ammonium iron(III)  sulfate dissolve and dissociate into irons. This irons diffuse through the entire solution. These salt ions eventually collide with each other forming colorful, insoluble compounds. When potassium hexacyanoferrate(II) and copper (II) ions meet, they form a brownish red precipitate of copper(II) potassium hexacyanoferrate(II) . Where as  potassium hexacyanoferrate(II) and iron(III) ions form a blue precipitate of iron(III) potassium hexacyanoferrate(II). This precipitate the ressubles real reefs.

₂CuSO₄ + K₄[Fe(CN)6] → Cu[Fe(CN)6]↓ + 2K₂SO₄

2K₄[Fe(CN)6] + 2NH₄Fe(SO₄)₂ → 2KFe[Fe(CN)6]↓ + (NH₄)₂SO₄ + 3K₂SO₄