When heated, potassium permanganate decomposes according to the following equation:
2KMnO4→K2MnO4+MnO2+O2
Given that the molecular mass of potassium permanganate is 158, what volume of oxygen (measured at room temperature) would be obtained by the complete decomposition of 15.8 g of potassium permanganate? (Molar volume at room temperature is 24 liters.)
Molar mass of KMnO4 =158
Molar volume of O2 at room temperature =24 litre
158 g of KMnO4 at room temperature yields 24 litres of O2
15.8 g of KMnO4 at room temp. will yield =242×158×15.8=1.2 litres of O2.