1) Balanced chemical reaction
2 KCl O3 ---> 2 KCl + 3 O2
2) stoichiometry
2 mol of KCl O3 / 3 mol O2
atomic and molecular masses
K: 39 g/mol
Cl: 35.5 g/mol
O: 16 g/mol
KClO3: 39 + 35.5 + 3*16 = 122.5 g/mol
O2: 2*16 = 32 g/mol
ratio of masses: 2* 122.5 g of K Cl O3 / 3* 32 g O2
4) final calculations
3.450 g KClO3 * 96 g O2 / 245 g KClO3 = 1.352 g O2
5) Answer: 1.352 gO2
