When this chemical equation, Al + O2 → Al2O3, is balanced, the coefficients (in order from left to right) are 4, 3, 2 2, 1, 1 4, 3, 3 2, 3, 2
The Correct Answer and Explanation is:
The correct answer is: 4, 3, 2
That means the balanced equation is:
4Al + 3O₂ → 2Al₂O₃
Detailed Explanation (Textbook Style):
Balancing chemical equations is essential in chemistry because it reflects the Law of Conservation of Mass, which states that matter cannot be created or destroyed in a chemical reaction. Therefore, the number of atoms for each element must be the same on both sides of the equation.
Let’s break down the process of balancing the unbalanced chemical equation:
Unbalanced Equation:
Al + O₂ → Al₂O₃
Step 1: Count atoms on both sides
Start by analyzing the number of atoms for each element:
- Left side:
Al = 1
O = 2 (from O₂) - Right side (in Al₂O₃):
Al = 2
O = 3
As we can see, the atoms do not match, so we must find coefficients (whole numbers in front of each compound or element) to make them equal.
Step 2: Balance aluminum (Al)
There are 2 Al atoms in Al₂O₃, so to balance Al on the left side, we place a 4 in front of Al:
4Al + O₂ → 2Al₂O₃
This gives:
- Al = 4 (on the left)
- Al = 4 (from 2 × Al₂ on the right) ✅
Step 3: Balance oxygen (O)
There are 3 oxygen atoms in 1 Al₂O₃, so in 2Al₂O₃, we have:
- O = 2 × 3 = 6
On the left, O₂ has 2 oxygen atoms. To get 6 atoms, we place a 3 in front of O₂:
4Al + 3O₂ → 2Al₂O₃
Now:
- O = 3 × 2 = 6 (on the left)
- O = 6 (on the right) ✅
Final Check:
- Al: 4 on both sides ✅
- O: 6 on both sides ✅
The equation is now fully balanced.
Final Balanced Equation:
4Al + 3O₂ → 2Al₂O₃
So, the correct coefficients in order from left to right are:
4, 3, 2 ✅
