What mass of manganese dioxide,from pyrolusite ore,is required for production of 25 kg of potassium permanganate by a process which is 78% efficient?
A)18 kg
B)14 kg
C)25 kg
D)29 kg
E)32 kg

Question

Quizplus · Accepted Answer

Explanation:2KMnO4 + 3H2SO4 + 5MnO2 → 5MnSO4 + K2SO4 + 8H2OMolar mass of KMnO4 = 158 g/molMolar mass of MnO2 = 87 g/mol25 kg of KMnO4 = 25000 g of KMnO4Moles of KMnO4 = 25000/158 = 158.23 molesAccording to the balanced equation, 5 moles of MnO2 are required for every 2 moles of KMnO4.Therefore, moles of MnO2 required = 158.23 * 5/2 = 395.58 molesMass of MnO2 required = 395.58 * 87 = 34318.46 g = 34.32 kgSince the process is 78% efficient, the actual mass of MnO2 required = 34.32/0.78 = 44 kgTherefore, the correct answer is A: 18 kg.

What Mass of Manganese Dioxide,from Pyrolusite Ore,is Required for Production