Al + O2 —> Al2O3 Balance the chemical equation.
The Correct Answer and Explanation is:
To balance the chemical equation:
Unbalanced Equation:
Al + O₂ → Al₂O₃
Balanced Chemical Equation:
4Al + 3O₂ → 2Al₂O₃
Explanation
Balancing chemical equations is a fundamental skill in chemistry. It ensures that the Law of Conservation of Mass is upheld, meaning the same number of each type of atom must appear on both sides of the equation. Let us analyze and balance the reaction of aluminum (Al) with oxygen gas (O₂) to form aluminum oxide (Al₂O₃).
Begin by writing the unbalanced equation:
Al + O₂ → Al₂O₃
Examine the number of atoms for each element on both sides:
- Left side (reactants):
- Al: 1 atom
- O: 2 atoms (because O₂ is a diatomic molecule)
- Right side (products):
- Al: 2 atoms (in Al₂O₃)
- O: 3 atoms (in Al₂O₃)
At this point, the number of aluminum and oxygen atoms does not match on both sides. Start by balancing the aluminum atoms. Since there are 2 Al atoms in Al₂O₃, place a 4 in front of Al on the left to make 4 Al atoms, which will correspond to 2 molecules of Al₂O₃ on the right (because 2 × 2 = 4):
4Al + O₂ → 2Al₂O₃
Now balance the oxygen atoms. The right side now has 2 × 3 = 6 oxygen atoms. Since each O₂ molecule has 2 oxygen atoms, to get 6 oxygen atoms, place a 3 in front of O₂:
4Al + 3O₂ → 2Al₂O₃
Now both sides have:
- 4 aluminum atoms
- 6 oxygen atoms
The equation is now balanced. This means that four aluminum atoms react with three oxygen molecules to produce two formula units of aluminum oxide. This balanced equation respects the conservation of mass, making it chemically accurate.
