Red Flame from Sugar

Mixture of solid substances ignites with a beautiful red flame.

Scientific name: Strontium burns with red color flame when a highly exothermic redox reaction takes place.

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Safety

Wear eye protection goggles. Perform this demonstration in the fume hood or outside. This is a violent reaction. Keep a safe distance. There is a serious fire risk - a fire extinguisher should be ready.

Always follow general safety recommendations. Please note that conducting chemistry experiments you must comply with the relevant legal procedures in your country.

Reaction formula

2Sr(NO3)2 + 4 KClO3 + C12H22O11 → 4KCl + 10CO2 + 2N2 + 2SrCO3 + 11H2O

Step-by-step instruction

WARNING! This experiment is dangerous! You should NOT perform this at home. ONLY carry out this experiment, if you are a trained chemist, and you understand local safety and legal requirements, which are required to perform such experiments

  1. Weight out separately 5 g of potassium chlorate, 10 g of strontium nitrate and 5 g of sugar.
  2. Prepare a beaker.
  3. Place the potassium chlorate into the beaker.
  4. Add strontium nitrate to the potassium chlorate. Then add sugar. Follow the mixing order.
  5. Mix the components gently. Do not use a spatula.
  6. Empty the beaker on a ceramic plate and ignite it using a gas burner.
  7. Mixture burns with a red flame.

Scientific background

This reaction could be considered as a strontium flame test. Each element has a characteristic emission spectrum. This feature allows to determine elements by their flame color. Strontium produces a red color.

Oxidation of sugar by chlorate and nitrate ions is a very exothermic reaction:

2Sr(NO3)2 + 4 KClO3 + C12H22O11 → 4KCl + 10CO2 + 2N2 + 2SrCO3 + 11H2O

The evolution of heat excites strontium atoms. Electrons move to higher energy levels. When they return to ground state they emit energy in the form of light of special wavelength. For strontium this wavelength corresponds to red light.

Danger:
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Published on 12 February 2015

  • Fire
  • Heating with fire
  • Explosion
  • Poisoned gas
  • Organic
  • Electricity
  • Solution
  • Oxidation reduction
  • Color change
  • Precipitate
  • Gassing
  • Catalyst