which of the chemical equation below shadows a balanced reactions that follows the law of conservation of matter
1. 2H2 + O2 -> 2H2O
2. N2 + 3H2 -> 2NH3
3. 4Fe + 3O2 -> 2Fe2O3
4. 2C2H6 + 7O2 -> 4CO2 + 6H2O
The chemical equation that represents a balanced reaction following the law of conservation of matter is:
4Fe + 3O2 -> 2Fe2O3