1. Balanced Chemical Equation:

The balanced chemical equation is:

2KClO₃ → 2KCl + 3O₂

2. Mole Ratios:

The equation tells us that 2 moles of KClO₃ decompose to produce 3 moles of O₂.

3. Convert Mass of O₂ to Moles:

* Molar mass of O₂ = 32 g/mol

* Moles of O₂ = 0.312 g / 32 g/mol = 0.00975 mol

4. Calculate Moles of KClO₃ Decomposed:

* Use the mole ratio from the balanced equation: (2 moles KClO₃ / 3 moles O₂)

* Moles of KClO₃ = 0.00975 mol O₂ * (2 mol KClO₃ / 3 mol O₂) = 0.0065 mol KClO₃

5. Convert Moles of KClO₃ to Mass:

* Molar mass of KClO₃ = 122.55 g/mol

* Mass of KClO₃ = 0.0065 mol * 122.55 g/mol = 0.796 g

Therefore, 0.796 g of KClO₃ was decomposed to produce 0.312 g of O₂.