Zinc blende (ZnS) weighing 6.5 kg with w (mass fraction)% of impurities 10%, it was burned in oxygen

Zinc blende (ZnS) weighing 6.5 kg with w (mass fraction)% of impurities 10%, it was burned in oxygen. Determine the V of the SO2 obtained.

Given:
m (ZnS) = 6.5 kg = 6500 g
ω approx. = 10%

To find:
V (SO2) -?

Decision:
1) 2ZnS + 3O2 => 2ZnO + 2SO2 ↑;
2) M (ZnS) = Mr (ZnS) = Ar (ZnS) * N (ZnS) + Ar (ZnS) * N (ZnS) = 65 * 1 + 32 * 1 = 97 g / mol;
3) ω (ZnS) = 100% – ω approx. = 100% – 10% = 90%;
4) m clean. (ZnS) = ω (ZnS) * m (ZnS) / 100% = 90% * 6500/100% = 5850 g;
5) n (ZnS) = m pure. (ZnS) / M (ZnS) = 5850/97 = 60.31 mol;
6) n (SO2) = n (ZnS) = 60.31 mol;
7) V (SO2) = n (SO2) * Vm = 60.31 * 22.4 = 1350.9 liters.

Answer: The volume of SO2 is 1350.9 liters.