Chemical demonstrations

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Chemical demonstrations that are amusing or impressive to watch.

Energetic materials

Explosive decomposition of Para-nitroaniline

Para-nitroaniline explodes, leaving an impressive mount of carbon behind under the attack of hot concentrated sulfuric acid.

Video: P-nitroaniline's decomposition demonstration

Mercury thiocyanate ("Pharaoh's snake")

Mercury(II) thiocyanate burns forming residues looking like tentacles growing from the ground.

Video: mercury thiocyanate's combustion demonstration

Video: Mercury thiocyanate and ammonium dichromate's combustion. "gates of hell" effect demonstration

Ammonium dichromate ("Volcano")

When ammonium dichromate burns, it looks like an erupting volcano.

Video: ammonium dichromate's combustion demonstration

Iodine and aluminium

When aluminium and iodine are combined in the presence of a small amount of water, they react to produce thick purple smoke and leaves a metallic coating on the glass.

Video: Iodine and aluminium demonstration

Color changes

Briggs-Rauscher oscillator

Very pronounced and rapid color changes repeating again and again and again.

Video: iodine oscillator demonstration

Iodine clock reaction

Colorless solutions becoming deep blue/black almost instantaniously after a small delay.

video: iodine clock demonstration and theory

Chameleon

5 vivid color changes in a row while the reaction passes through the many different oxidation states of manganese.

Video: Chameleon demonstration

Light emission

Fluorescent pH indicator

Pyranine, present in highlighter fluid, will fluoresce different colors in different levels of acidity.

Smash-glow crystals

Sugar will emit ultraviolet light when crushed. When a fluorescent dye such as methyl salicylate is used, the fluorescence is made much brighter.

Miscellaneous

Elephant toothpaste

The rapid decomposition of hydrogen peroxide with a catalyst (usually potassium iodide or yeast) in soapy water generates a huge amount of hot foam due to oxygen generation.

Video: Elephant toothpaste demonstration

Carbon snake

Materials needed: granular sugar and concentrated (98%) sulfuric acid, acid resistant gloves

Procedure: Pour concentrated sulfuric acid directly onto sugar.

Result: a tower of porous carbon forms after a delay period.

Video: carbon snake demonstration

Alkali metals

In the presence of water

Lithium will effervesce strongly

Sodium will do so more strongly and may catch fire

Potassium catches fire

Rubidium and caesium will explode.

https://www.youtube.com/watch?v=uixxJtJPVXk