Chem Ace Firework

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  • 1. The Chemistry Behind Fireworks By Darryl Ho4L04

2.

  • What is a firework ?
  • What are fireworks made of ?
  • The chemistry behind fireworks
  • Stage 1 : Redox Reaction
  • Stage 2 : Excitement of electrons
  • Effect: Different metals, Different colours

Content 3. What is a Firework ? It is a low explosive pyrotechnic device used primarily for special effects and entertainment purposes. 4.

  • Oxidising Agent
  • Firework Rocket Fuel
  • Gunpowder
  • Colouring Agent
  • Binder

What is a Firework Made Of ? 5. Stage ILift Off 6. STAGE I - The Lift Off Redox reaction between the oxidising agents and the rocket fuel 7.

  • Thermal decomposition of oxidising agents
  • OxidisingAgents used : KNO 3 , KClO 4 , KClO 3
  • Potassium nitrate is reduced into potassium oxide and nitrogen gas as it loses oxygen.
  • Thus reduction of potassium nitrate takes place and oxygen gas is produced.

STAGE I - Redox Reaction 4 KN O 3 4 K 2 O + 2N 2 +5O 2 8.

  • Oxidation of rocket fuel
  • Rocket Fuel: Carbon + Sulphur Powder
  • Sulphur and carbon reacts with the oxygen provided by the reduction of oxidising agents to form sulphur dioxide and carbon dioxide respectively
  • Both sulphur and carbon are oxidised to gain oxygen, forming large amounts of sulphur dioxide and carbon dioxide as products.

2 STAGE I - Redox Reaction O (g) +S (s) SO (g) 2O (g) +C (s) CO (g) 222 9.

  • Large volumes of carbon dioxide and sulfur dioxide gases are formed.
  • They exert a force on the ground due to high pressure in the rocket, creating
  • an upward thrust on the rocket.
  • This lifts the rocket into the air.

The Result 10. Excitement of electrons of metal atoms STAGE II Excitement of Electrons 11. STAGE II - Heating of Colouring Agents

  • Coloring agents used are salts of metals or their compounds.
  • The metal atoms or cations absorb the thermal energy produced by the combustion of sulfur and carbon powder.
  • The thermal energy that is absorbed causes the electrons of the atom from the lowest energy state to become excited and enter the highest energy state of an atom, called an excited state.

12.

  • The excess energy of the excited state is released as the electrons descend to lower energy states.
  • The energy released is emitted as light energy in the process.

STAGE II - Heating of Colouring Agents 13. The End Result 14. Effect - Different Metals .Different Colours

  • The electrons of different metals release different amount of energy when excited and produce an electromagnetic wave of a particular wavelength.
  • Hence, different metals produce different colors of light when burnt.

Higher Energy Lower Energy Shorter Wavelengths Higher Wavelengths 15. Effect - Different Metals .Different Colours COLOUR CHEMICAL WAVELENGTH Red

  • Lithium Salts

650 nm Orange

  • Calcium Salts
  • Calcium (II) Chloride

670 nm Yellow

  • Sodium Salts
  • Sodium Chloride

610 nm Blue

  • Copper(I) Chloride

535 nm Silver

  • Magnesium, Aluminium
  • and Titanium Salts

16. The End. Thank You.