Determination Of The Chemical Formula Of Magnesium Oxide

This investigation is about proving the formula of magnesium oxide by making magnesium oxide. The first reactant of the experiment is magnesium metal (Mg) and oxygen (O2), the oxygen will be in the air and provide oxygen atoms for the formation of magnesium oxide (MgO), which is the product of this experiment (In association with Nuffield Foundation). We are performing this experiment to improve our critical thinking skills as we will have to analyse the data and results to form conclusions, and to familiarise ourselves with laboratory procedures and equipment.

"What is the chemical formula of magnesium oxide"

My hypothesis is that the chemical formula for magnesium oxide is MgO, and the equation for it would be 2Mg + O2 → 2MgO.

Magnesium

Monitor the reaction and when when the reaction is near completion let some smoke escape by tilting the lid of the crucible

When the reaction ceases, turn off the Bunsen burner and let the crucible cool completely before handling it.

Weigh the crucible and record the weight

Using a pipette, add a small volume of water to the solids in the crucible

Stir the mixture with a glass rod until the mixture forms a paste

Return the crucible to the Bunsen burner and heat it for several minutes until all the water has evaporated and the solids have turned light grey → indicating conversion to magnesium oxide.

Turn off the Bunsen burner and let the crucible cool completely

Weigh the crucible with the lid and record the weight

Subtract the initial weight of the crucible and lid from the final weight of the crucible, lid, and magnesium oxide to obtain the mass of magnesium that reacted with oxygen. → this information will be used to calculate the empirical formula for magnesium oxide and prove it.

Clean the crucible thoroughly to ensure it's ready for the next use.

(crharrison)

Safety measures/hazards

Safety goggles to avoid potential debris from harming eyes and

As discussed in the conclusion, based on my results the formula for magnesium oxide is MgO2, meaning that the ratio for magnesium atoms to oxygen atoms is 1:2. These results are incorrect because magnesium has a charge of 2+ and oxygen has a 2- charge, so when the elements are combined with each other, they balance when forming a stable compound. Which results in the formula being MgO rather than MgO2. My results may have come out like this because of the many unfortunate errors my group and I made during the experiment. Missing a measuring point during the experiment led to most likely inaccurate measurements, which inevitably led to wrong calculations. Also our group added too much water into the crucible, which diluted the mixture, which most likely slowed the reaction, or even led to an incomplete reaction which would affect the mole ratios and therefore the empirical formula. Lastly, there could have been residue from other experiments on some of our apparatus, which could have introduced other elements to the reaction and that would also obviously lead to an incorrect