Determine the Empirical Formula of Magnesium Oxide

Aim: The aim of this experiment was to determine the empirical formula of magnesium oxide.

Hypothesis: If a known mass of magnesium is heated in air, then the empirical formula of the compound formed between magnesium and oxygen can be determined.

Equipment: Crucible and lid, bunsen burner, tripod stand, clap pipe triangle, bench protector mat, magnesium ribbon (Mg), tongs, emery paper or steel wool, safety glasses and 2-place balance.

Method/Procedure: Cleaned a crucible and lid and heated strongly for about 5 mins in a non-luminous flame. Then Allowed crucible and lid to cool down and recorded the total mass of the crucible and lid. A piece of magnesium ribbon was cleaned thoroughly for about 5 mins until the surface was shiny. The piece of ribbon was there after coiled with a pen and placed into the crucible. The mass of the crucible and magnesium was recorded. Then the crucible with its lid on was placed on the clay triangle. The crucible was heated with a non-luminous flame for approx 10 mins while occasionally raising the lid to provide oxygen for reaction. The lid was lifted carefully to avoid the loss of magnesium oxide smoke. After all magnesium had reacted and no more smoke was being given off the lid was removed and the crucible was heated for a further 5 minuted. After this time the crucible was allowed to cool and thereafter weighed and recorded.

Results:

Mass of crucible and lid 40.50g

Mass of crucible and lid and magnesium 40.67g

Mass of crucible and lid and magnesium oxide 40.76g

Mass of magnesium (40.67-40.50) = 0.17g

Mass of magnesium oxide (40.76-40.50) = 0.26g

Mass of oxygen (Combined with magnesium) (40.76-40.67)