Determining the Empirical Formula of Magnesium Oxide

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Chemistry Lab Report example:

Chemistry Laboratory Report (Magnesium Oxide)


As we learned before on how to determine the empirical formula of a compound based on the test and also chemical analysis on it. Hence this experiment is mainly goes around with how to determine the empirical formula of Magnesium Oxide following various tight procedures in order to get the knowledge and apply it onto another compounds. We are investigating the empirical formula of Magnesium Oxide in this experiment.


How empirical formula of Magnesium Oxide is obtained by heating Magnesium in the presence of air?


When Magnesium and Oxygen are heated together, they readily undergo a chemical change

Magnesium + Oxygen = Magnesium Oxide

From the combination of chemical properties between Magnesium and Oxygen, we can absolutely calculate the empirical formula Magnesium Oxide, we measure the mass of the Magnesium initially and the mass of Magnesium Oxide yet we can just find the difference between Magnesium Oxide and Magnesium to get the ‘mass’ of the Oxygen. This method seems more beneficial rather that measuring the mass of Oxygen initially.

If Magnesium is being heated in open air, it has very obvious and rapid reaction as the metal meet fire and burns with an intense white flame with the white smoke as a product. Thus we can slow down the process by limiting the supply of oxygen that reaches the Magnesium by placing a lid on the crucible.


Dependant: Mass of Magnesium Oxide(g)


Possible effect on result
Method of controlling
Mass of Magnesium ribbon
The amount of mass either less/more will affect the accuracy of the result obtained Use the same mass of Magnesium ribbon in each repeated trials which is 0.3 g 2)
Time interval to open the lid
The time interval to open the ld either less/more will affect the accuracy of the result obtained Use the same time interval top open the lid to allow the oxygen gas to enter in for every 30 s


Safety Goggles, crucible, crucible lid, clay triangle, tripod stand, wire gauze, Bunsen burner, electronic balance, Magnesium ribbon, stopwatch, filter paper, tongs


1. Magnesium is a flammable metal. Magnesium burns with an intense flame. Do not look directly at burning Magnesium. The light contain UV light that harmful to eyes.

2. Always wear safety goggles.

3. Do not inhale the smoke produced when the magnesium is burned.

4. Do not loose smoke! The more smoke loose, the more difficult to determine the empirical formula.

5. Carefully pre-heat the crucible. If the crucible is thrown on the flame, the crucible might be cracked and we have to restart.

6. Handle the crucible and its lid only with tongs. Do not touch the crucible with fingers or hand. There is a significant burn hazard associated with handling the crucible. Wash hands thoroughly with soap and water before leaving the lab.


1. The crucible and its lid is cleaned and rinsed with ionized water.

2. The clean and dry crucible is placed on the clay triangle, and heated for 5 minutes to remove any volatile material.

3. While the crucible is heated, the magnesium ribbon(0.3g) is cleaned with using sandpaper to remove any oxide roating, the process is not done by using finger since it will leave deposits on magnesium ribbon

4. By using crucible tongs, the crucible and its lid are removed from the clay triangle and placed on wire gauze to cool.

5. When the crucible and the lid is totally cool, the crucible is weighed

6. The ribbon is coiled and placed into the crucible. The mass is recorded.

7. The lid is placed and the crucible is heated for 5 minutes, while tongs is used to lift the lid for every 30 seconds to admit air. When magnesium started to glow brightly, the crucible is quickly covered and the Bunsen...
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