Experiment: Empirical Formulae Using Magnesium

Objective

• Determine the empirical formula of magnesium through a controlled reaction.

Materials

• Magnesium ribbon
• Crucible with lid
• Bunsen burner
• Ring stand and clay triangle
• Steel wool
• DI water
• Pipette
• Balance

Procedure

Preparation

1. Set Up:

   • Connect tubing to the blue gas line in the hood.
   • Attach to Bunsen burner.
   • Clamp a ring stand with a clay triangle on top.
   • Place crucible with lid on the clay triangle.

2. Initial Heating:

   • Heat empty crucible with a blue flame for about 5 minutes.
   • Allow to cool and weigh the empty crucible with lid.

Reaction

3. Prepare Magnesium Ribbon:

   • Cut a piece slightly longer than a ruler.
   • Clean oxide coating from magnesium using steel wool.
   • Coil magnesium to fit in crucible.

4. Weighing:

   • Weigh empty crucible and lid.
   • Tear the balance and add coiled magnesium ribbon.

5. Heating Magnesium:

   • Place crucible with magnesium partially open on clay triangle.
   • Adjust ring clamp for optimal heating.
   • Heat for about 10 minutes.
   • Remove flame, open lid, and keep partially open.
   • Heat for an additional 5 minutes.

6. Reactions with Water:

   • Cool crucible for about 10 minutes.
   • Add 10 drops of DI water using a pipette.
   • Replace lid and heat for another 10 minutes.

Final Steps

7. Cooling and Weighing:

   • Allow crucible to cool for 15 minutes.
   • Weigh the final product.

8. Disposal:

   • Dispose of product in labeled waste container.

Observations

• Magnesium initially has a gray oxide coating.
• Cleaning reveals a shiny metallic surface.
• Reaction product should appear as described.

Notes

• Ensure the crucible cools fully before weighing.
• Maintain a blue flame for optimal heating.
• Use appropriate waste disposal methods.