The balanced equation for this reaction is:
2 KCIO3(s) → 2 KCI(s) + 3 O2(g)
From the equation, we can see that every 2 mol of KCIO3 produces 3 mol of O2. Therefore, the number of moles of KCIO3 required to produce 0.50 mol of O2 is:
0.50 mol O2 × (2 mol KCIO3 / 3 mol O2) = 0.33 mol KCIO3
The molar mass of KCIO3 is 122.55 g/mol. Therefore, the mass of KCIO3 required is:
0.33 mol KCIO3 × 122.55 g/mol = 40.42 g KCIO3
So, you would need 40.42 g of KCIO3 to produce 0.50 mol of O2.