How would the formula of the oxide be influence if impure magnesium was used?

Answer 1

The formula of the magnesium oxide formed would not change at all if impure magnesium was used, but less of the magnesium oxide would be formed than if the same amount of pure magnesium had been used. Depending on the chemical nature of the impurities, other products might be formed, or the impurity might simply remain as a contaminant of the magnesium oxide.

Answer 2

If impure magnesium is used, the formula of the magnesium oxide produced would likely be affected by the presence of other impurities. The impurities may react with oxygen to form additional compounds, leading to a mixture of magnesium oxide and other oxides in the final product. This can alter the stoichiometry and composition of the oxide formed.