Final answer:
To calculate the mass of KClO3 necessary to produce 1.23g of O2, we can use stoichiometry. From the given information, we find that the mass of KClO3 needed is 4.92 grams.
Step-by-step explanation:
To calculate the mass of KClO3 necessary to produce 1.23g of O2, we need to use stoichiometry. From the given information, we know that 1 mol KClO3 is equal to 122.55g, and 1 mol O2 is equal to 32.00g. Using these conversion factors, we can set up the following equation:
(1.23g O2) x (1 mol O2 / 32.00g O2) x (1 mol KClO3 / 1 mol O2) x (122.55g KClO3 / 1 mol KClO3) = 4.92g KClO3
Therefore, the mass of KClO3 necessary to produce 1.23g of O2 is 4.92 grams. The correct answer is D. 4.92g.