posted by B .
Potassium nitrate decomposes on heating, producing potassium oxide and gaseous nitrogen and oxygen:
4KNO3(s)--> 2K2O(s) + 2N2(g) + 5O2(g)
To produce 56.6 kg of oxygen, how many (a) moles of KNO3 must be heated? (b) Grams of KNO3 must must heated?
Here is a worked example of a stoichiometry problem such as this one.