Final answer:
To find the mass of oxygen gas produced from 125 g of KClO3, a balanced chemical equation is used along with molar masses to convert grams to moles and then to calculate the theoretical yield, resulting in 48.96 g of O2.
Step-by-step explanation:
To determine the mass of oxygen gas produced from the decomposition of 125 g of KClO3, we will follow these steps:
- First, write the balanced chemical equation for the decomposition of potassium chlorate: 2 KClO3 (s) → 2 KCl (s) + 3 O2 (g).
- Next, calculate the molar mass of KClO3 and O2. The molar mass of KClO3 is 122.55 g/mol and the molar mass of O2 is 32.00 g/mol.
- Convert the mass of KClO3 to moles: 125 g KClO3 × (1 mol KClO3 / 122.55 g KClO3) = 1.020 mol KClO3.
- Use the stoichiometry of the balanced equation to find the moles of O2 produced: 1.020 mol KClO3 × (3 mol O2 / 2 mol KClO3) = 1.530 mol O2.
- Finally, convert the moles of O2 to grams: 1.530 mol O2 × (32.00 g O2 / 1 mol O2) = 48.96 g O2.
Therefore, the theoretical yield of oxygen gas when 125 g of KClO3 is decomposed completely is 48.96 g.