Which chemical equation below is balanced to correctly represent the Law of Conservation of Mass? 04 Al + 3O2 + 2 Al2O3 O2 AL + O2 + 2 Al2O3 O AL + O2 + Al2O3
The Correct Answer and Explanation is:
Correct Answer:
4 Al + 3 O₂ → 2 Al₂O₃
Explanation (Like in Textbooks):
To determine which chemical equation correctly represents the Law of Conservation of Mass, we must understand what this law means. The Law of Conservation of Mass states that matter cannot be created or destroyed in a chemical reaction. Therefore, the total number of atoms of each element must be the same on both sides of the equation.
Step-by-Step Analysis:
Let’s analyze the correct chemical reaction involving aluminum (Al) and oxygen gas (O₂) forming aluminum oxide (Al₂O₃):
Unbalanced Reaction:
Al + O₂ → Al₂O₃
Now, let’s count the atoms on each side:
- Left Side:
- Al: 1 atom
- O: 2 atoms (since O₂ is diatomic)
- Right Side:
- Al: 2 atoms (in Al₂O₃)
- O: 3 atoms (in Al₂O₃)
This equation is not balanced because the number of aluminum and oxygen atoms are not equal on both sides.
Balancing the Equation:
To balance the atoms:
- Balance Aluminum (Al):
- On the right, Al₂O₃ has 2 aluminum atoms.
- Multiply Al on the left by 4 to balance with 2 Al₂O₃ molecules:
4 Al + O₂ → 2 Al₂O₃
- Balance Oxygen (O):
- 2 Al₂O₃ contains 2 × 3 = 6 oxygen atoms.
- To get 6 oxygen atoms from O₂, we need 3 O₂ molecules:
4 Al + 3 O₂ → 2 Al₂O₃
Now both sides have:
- Aluminum: 4 atoms
- Oxygen: 6 atoms
Final Balanced Equation:
4 Al + 3 O₂ → 2 Al₂O₃
This balanced chemical equation correctly follows the Law of Conservation of Mass, ensuring that the number of atoms of each element is equal on both sides of the reaction.
