Answer:
P₄O₆ + 2O₂ ⟶ P₄O₁₀
Step-by-step explanation:
We have two equations:
(I) P₄ + 3O₂ → P₄O₆
(II) P₄ + 5O₂ → P₄O₁₀
From these, we must devise the target equation:
(III) P₄O₆ + __O₂ ⟶ P₄O₁₀
The target equation has P₄O₆ on the left, so you reverse Equation (I).
(IV) P₄O₆ ⟶ P₄ + 3O₂
The target equation has P₄O₁₀ on the right, so we rewrite Equation (II).
(II) P₄ + 5O₂ → P₄O₁₀
Now, you add Equations (IV) and (II), cancelling species that appear on opposite sides of the reaction arrows.
We get the target Equation (III):
(IV) P₄O₆ ⟶ P₄ + 3O₂
(II) P₄ + 52O₂ ⟶ P₄O₁₀
(III) P₄O₆ + 2O₂ ⟶ P₄O₁₀
