Calculate the mass of potassium permanganate that is required to obtain 2 g of oxygen.

univerkov | September 15, 2021 | education

1) The amount of substance of the obtained oxygen: νО2 = mО2 / MO2, where mО2 is the considered mass of oxygen (mО2 = 2 g); MO2 is the molar mass of oxygen (MO2 = 32 g / mol).

Calculation: νО2 = mО2 / MO2 = 2/32 = 0.0625 mol.

2) Getting oxygen: О2 + MnO2 + K2MnO4 = 2КMnO4.

3) The ratio of the amount of substance: νО2 / νКMnO4 = 1/2, whence we express: νКMnO4 = 2 * νО2 = 2 * 0.0625 = 0.125 mol.

4) Molar mass of KMnO4: MKMnO4 = 39 * 1 (potassium) + 55 * 1 (manganese) + 16 * 4 (oxygen) = 158 g / mol.

5) The required mass of KMnO4: mKMnO4 = νKMnO4 * MKMnO4 = 0.125 * 158 = 19.75 g.

Answer: You will need 19.75 g of potassium permanganate.

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