The balanced chemical equation :
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
Further explanation
Conservation of mass applies to a closed system, where the masses before and after the reaction are the same, so balanced chemical equations show that mass is conserved in chemical reactions.
So we just have to look at the amount of each type of element present in the reactants and products must be the same
1. 2H₂ + O → H₂O
not balanced, because element H not equal(4 in left, 2 in right)
2. C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
balanced, because elements in reactant and product are the same
3. N + 3H₂ → 2NH₃
not balanced, because element N not equal(1 in left, 2 in right)
4. C₃H₈ + 4O₂ → 3CO₂ + 4H₂O
not balanced, because element O not equal(8 in left, 10 in right)
