For the oxidation of a certain amount of sulfur, such a volume of oxygen was required, which is formed during

For the oxidation of a certain amount of sulfur, such a volume of oxygen was required, which is formed during the decomposition of 665.3 g of potassium permanganate containing 5% anoxic impurities. Determine the mass of sulfur that can react and the volume of the formed oxidation product.

Given:
m tech. (KMnO4) = 665.3 g
ω (approx.) = 5%

To find:
m (S) -?
V (product) -?

1) 2KMnO4 => K2MnO4 + MnO2 + O2;
S + O2 => SO2;
2) ω (KMnO4) = 100% – ω (approx.) = 100% – 5% = 95%;
3) m clean. (KMnO4) = ω * m tech. / 100% = 95% * 665.3 / 100% = 632.04 g;
4) n (KMnO4) = m pure. / M = 632.04 / 158 = 4 mol;
5) n (O2) = n (KMnO4) / 2 = 4/2 = 2 mol;
6) n (S) = n (O2) = 2 mol;
7) m (S) = n * M = 2 * 32 = 64 g;
8) n (SO2) = n (O2) = 2 mol;
9) V (SO2) = n * Vm = 2 * 22.4 = 44.8 liters.

Answer: The mass S is 64 g; the volume of SO2 is 44.8 liters.