DRAFT: This module has unpublished changes.


  • Crucible and lid
  • Ring stand
  • Bunsen Burner
  • Balance
  • Crucible tongs
  • Wash bottle with deionized water
  • Clay triangle
  • Paper clip
  • Magnesium powder 0.5 g


  1. Be careful using the bunsen burner.
  2.  Never place objects near or on the balance pan.
  3. Do not move crucible until cooled.
  4.   Make sure nothing is flammable near the set up.


  1. Find the mass of crucible and lid and record it.
  2. Prepare crucible by heating it to remove any impurities which would make it have a more accurate reading.
  3. Heat, cool and measure mass of crucible until there ar two readings within 10 mg of each other. Record mass in table 1.

Table 1: Mass of the Empty Crucible measured to the nearest milligram

Measurement Trial 1

Crucible and lid before heating (g)

Crucible and lid after first heating (g) 38.103
Crucible and lid after second heating (g) 38.102

    4. Add between 0.17 g and 0.23 g of Mg to crucible and measure the mass to the nearest milligram.


5.  Return sample to Bunsen burner and heat sample for 2-3 minutes around the bottom. Increase heat and continue until the sample starts to glow.


6. Manage burning until magnesium glows for 3 minutes.


7. Contine heating for 3 minutes and lift lid. When the bright glow turns to a pale glow, stop heating.


8. Break the crust over contents and mix with the paper clip. All of the unreacted metal needs to be brought to the surface to make sure all of it reacts.


9. Repeat steps 5-8.


10. After cooing, add 3 drops of deionized water.


11.  Identify the smell of ammonia. It has a strong, harsh scent.


12. Heat sample. Have the lid slightly open and heat for 3 minutes. Gradually increase heat and heat on high for 15-20 minutes. Stop when it is a pale glow.


13. Record the mass in table 2.


Table 2: Mass of the Crucible and Magnesium Oxide, measured to nearest mg

Measurement Trial 1
Crucible, lid and MgO after the first heating (g) 38.382
Crucible, lid and MgO after the second heating (g) 38.369
Crucible, lid and MgO after the third heating (g) 38.370

14. Reheat for 5 minutes. Record mass and repeat until there are two readings within 10 milligrams of each other.


15.  Dispose waste in appropriate container.


16. Wash crucible with soap and rinse 3 times with tap water. Rinse again with deionized water.

DRAFT: This module has unpublished changes.
Example Image
DRAFT: This module has unpublished changes.