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

  

Invisible Ink with baking soda and vinegar

We can make non-toxic invisible ink using baking soda with in few minutes the advantages of using of backing soda are that it is safe for even kids, simple to use and cheaper

Reagents and Equipment 

1. Baking soda
2. Paper
3. Water
4. Light bulb(heat source)
5. Paint brush
6. Measuring cup
7. Purple grape juice (optional)

Step by step procedure

• Mix equal parts of water and baking soda.
• Use a tooth pick or paint brush to write a message in the white paper using the baking soda solution as ink.
• Allow the ink to dry.
• Ways to read the message 
1. Hold the paper up to a heat source or iron it. The baking soda will cause the writing in the paper to turn brown 
2. Paint over the paper with purple grape juice. As the concentration of grape juice increases visibility of color change increases.

Process

      Writing a message using baking soda solution disrupts the cellulose fibers in the paper, damaging the surface. When heat is applied exposed ends of fibers becomes darken. On applying too much heat, there is a risk of igniting the paper. So it is better to use either the grape juice or a controllable heat source

     The grape juice act as a pH indicator that changes color when it react with the sodium bicarbonate of baking soda which is a base. That acid base reaction.

How to make a chemical volcano

The baking soda and vinegar volcano resembles a real volcanic irruption, which is an example of an acid-base reaction. It is simple and fun for kids science experiment. 

The chemical vinegar  and baking soda produces carbon dioxide gas which forms bubbles in the dish-washing detergent. The chemicals used are non-toxic making this experiment a good choice for scientists of all ages.

Reagents and Equipment

• Flour (3 cups)
• Salt (1 cup)
• Water (1 cup)
• Cooking oil (2 table spoon)
• Empty drink bottle
• Pan or plate
• Food coloring
• Dish-washing detergent
• Baking soda 
• vinegar 

Procedure

1. For preparing the volcano dough, mix 3 cups of flour, 1 cup salt, 1 cup water and 2 table spoon cooking oil. Stir the dough well with your own hands or with a spoon until it becomes smooth if you like add a few drops of food coloring to the dough to make the volcano colored 
2. Fill the empty drink bottle with hot water. Then add dish-washing detergent and baking soda. Also you can add food coloring too. Set the bottle in the center of  a pan. Press the dough around the bottle and shape it to a volcano.
3. Pour some vinegar into the bottle. Then you can see the volcano begins to erupt with the overflow of lava. You can trigger the reaction by adding more baking soda and vinegar.
4. Spills can be clean up with warm soapy water.

Note: Don't try to eat the volcano even though chemicals used are non-toxic

Process

The reaction between baking soda and vinegar is merely an acid-base reaction

NaHCO3 + CH3COOH → CO2 + H2O + Na+ + CH3COO-

break down it as:

NaHCO3 → Na+ + HCO3-

CH3COOH → H+ + CH3COO-

H+ + HCO2- → H2CO3

H2CO3 → H2O + CO2

CO2 gas is responsible for the fizzing and bubbling during the irruption