Procedure of the experiment:
- Magnesium ribbon is cleaned with sandpaper to remove the oxide layer on its surface.
- The lid is removed at intervals to allow oxygen to enter the crucible and react with magnesium.
- The crucible is then quickly covered with its lid to prevent the white fumes of MgO from escaping.
- Heating, cooling and weighing are repeated until a constant mass is obtained to ensure that the magnesium ribbon reacts completely with oxygen gas.
The white powder is magnesium oxide