The burning of a magnesium ribbon in air is a classic chemistry experiment that demonstrates the reaction between magnesium and oxygen to form magnesium oxide. Here’s a step-by-step guide:
Materials Needed:
- Magnesium ribbon
- Tongs
- Bunsen burner or spirit lamp
- Watch-glass
- Sandpaper (optional, for cleaning the ribbon)
Procedure:
- Preparation of Magnesium Ribbon: If the magnesium ribbon is tarnished (appears dull), use sandpaper to clean it by rubbing gently. This removes the oxide layer and ensures the ribbon burns more easily.
- Lighting the Bunsen Burner: Light the Bunsen burner and adjust it to get a blue, non-luminous flame.
- Burning the Magnesium Ribbon:
- Using tongs, hold one end of the magnesium ribbon and bring the other end into the flame. The magnesium ribbon will ignite, emitting a bright white light. Avoid looking directly at the flame, as the light is intense.
- As the magnesium burns, it reacts with oxygen in the air to form magnesium oxide (MgO).
Chemical Equation:
\[ 2\text{Mg} + \text{O}_2 \rightarrow 2\text{MgO} \] - Collection of Magnesium Oxide:** - Hold the burning ribbon over a watch-glass. As the reaction progresses, a white powder (magnesium oxide) will form and fall onto the watch-glass. - Once the ribbon has completely burned, place any remaining ashes or residue onto the watch-glass.
- Observation:** - Observe the white powder (magnesium oxide) collected on the watch-glass. This powder is the product of the combustion of magnesium in oxygen.
Safety Precautions:
- Do not look directly at the burning magnesium as it emits an intense light that can harm your eyes.
- Handle the hot ribbon and magnesium oxide with care to avoid burns.
- Conduct the experiment in a well-ventilated area.
This experiment vividly illustrates a chemical reaction involving combustion and the formation of a compound from an element and oxygen.