1. The Balanced Chemical Equation:
The balanced chemical equation for the reaction is:
4 Al + 3 O₂ → 2 Al₂O₃
2. Oxidation Numbers:
* Aluminum (Al) in its elemental form: The oxidation number of an element in its pure form is always 0.
* Oxygen (O₂) in its elemental form: The oxidation number of an element in its pure form is always 0.
* Aluminum in aluminum oxide (Al₂O₃): Oxygen typically has an oxidation number of -2. Since there are two aluminum atoms (Al) and three oxygen atoms (O) in the formula, the oxidation number of aluminum must be +3 to balance out the charge.
3. Change in Oxidation Number:
* Aluminum: The oxidation number of aluminum changes from 0 (in its elemental form) to +3 (in aluminum oxide). This is an increase of +3.
* Oxygen: The oxidation number of oxygen changes from 0 (in its elemental form) to -2 (in aluminum oxide). This is a decrease of -2.
Conclusion:
The change in oxidation number of aluminum in the reaction with oxygen to form aluminum oxide is +3. This indicates that aluminum is oxidized in this reaction.
