demonstrations:burning_magnesium_ribbon

Burning Magnesium Ribbon

Materials: ★★☆ Available in most school laboratories or specialist stores
Difficulty: ★★☆ Can be done by science teachers
Safety: ★★☆ Some safety precautions required to perform safely

Categories: Chemical Reactions, Combustion, Elements and Periodic Table

Alternative titles: Bright Light Magnesium Reaction

Summary

A strip of magnesium ribbon, when ignited, burns with an intense white flame, producing magnesium oxide. The reaction is highly exothermic and demonstrates how metals can react vigorously with oxygen.

Procedure

  1. Cut a strip of magnesium ribbon about 10 cm (4 inches) long.
  2. Hold the ribbon securely with a pair of tongs.
  3. Place the ribbon into the hottest part of a lighter or Bunsen burner flame until it ignites.
  4. Step back slightly and observe the bright white light as the magnesium burns and forms a white powder of magnesium oxide.
  5. Allow the ash to cool before disposal.

Burning magnesium ribbon - DonoChem:


Chemistry Demo: Burning Magnesium - Dr. B's Chemistry:


📄 Burning Magnesium - LibreTexts Chemistry: https://chem.libretexts.org/Ancillary_Materials/Demos_Techniques_and_Experiments/Lecture_Demonstrations/Burning_Magnesium

Variations

  • Compare burning magnesium ribbon to burning other metals such as iron wool.
  • Place burning magnesium in a controlled container of carbon dioxide to show that it continues to burn, forming magnesium oxide and carbon.

Safety Precautions

  • Wear safety goggles with UV protection; the bright flame produces ultraviolet light that can damage eyes.
  • Do not look directly at the burning magnesium; view indirectly.
  • Keep away from combustible materials.
  • Handle with tongs; do not touch magnesium during or after burning.
  • Do not attempt to extinguish magnesium with water or carbon dioxide, as these can intensify the fire. Use only Class D fire extinguishers or cover with dry sand.
  • Do not allow children to perform this experiment.

Questions to Consider

  • Why is magnesium able to burn so brightly in air? (Magnesium atoms release large amounts of energy when reacting with oxygen, forming MgO.)
  • What type of reaction is burning magnesium? (A combustion reaction and also a redox reaction: magnesium is oxidized, oxygen is reduced.)
  • Why can’t water or carbon dioxide be used to extinguish a magnesium fire? (Magnesium reacts with water to release hydrogen gas, and with CO2 to release carbon—both reactions intensify the fire.)
  • What is the balanced equation for burning magnesium in air? (2Mg(s) + O2(g) → 2MgO(s).)
  • Why is the reaction exothermic? (Energy is released as strong ionic bonds form between Mg2+ and O2− ions in magnesium oxide.)