Oxygen gas can be prepared in the laboratory by heating potassium chlorate, so that it decomposes according to the equation: 2KClO₃(s) → 2KCl(s) + 3O₂(g)
What would the pressure of O₂ be in a 2.50 L glass container at 22.0^oC if 6.50 g of KClO₃ is decomposed?

Question

Quizplus · Accepted Answer

First, calculate moles of KClO3: 6.50 g / 122.55 g/mol = 0.0531 mol. From the equation, 2 mol KClO3 produces 3 mol O2, so 0.0531 mol KClO3 produces 0.07965 mol O2. Use the ideal gas law: PV = nRT. P = nRT/V = (0.07965 mol)(0.0821 L·atm/mol·K)(295 K) / 2.50 L = 0.771 atm.

Oxygen Gas Can Be Prepared in the Laboratory by Heating