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)

First, convert the amount of KNO3 to moles using the molar mass:

58.6 g / 101.11 g/mol = 0.5796 mol KNO3

Next, using the given balanced reaction, use the stoichoimetric ratio to calculate the number of mole of oxygen that will be produced. From the reaction, for every 4 moles of KNO3 that decomposes, there are 5 moles of O2 formed. So,

0.5796 mol KNO3 x (5/4) = 0.7254 moles O2

Therefore, when 58.6 g of KNO3 decomposes, there are 0.7254 moles of O2 that will be formed.