How many moles of oxygen are formed when 58.6 g of KNO₃ decomposes according to the following reaction? The molar mass of KNO₃ is 101.11 g/mol.
4 KNO₃(s) → 2 K₂O(s) + 2 N₂(g) + 5 O₂(g)

Question

Quizplus · Accepted Answer

First, we need to find the number of moles of KNO₃: 58.6 g KNO₃ / 101.11 g/mol KNO₃ = 0.5796 mol KNO₃ According to the balanced equation, for every 4 moles of KNO₃, 5 moles of O₂ are produced. Therefore, we can set up a proportion: 4 mol KNO₃ / 5 mol O₂ = 0.5796 mol KNO₃ / x mol O₂ Solving for x, we get: x mol O₂ = (5 mol O₂)(0.5796 mol KNO₃) / (4 mol KNO₃) = 0.7245 mol O₂ Rounding to three significant figures, we get: x mol O₂ = 0.724 mol O₂ Therefore, the answer is D) 0.724 mol O₂.

How Many Moles of Oxygen Are Formed When 58