A sample of technical iron sulfide weighing 9.8 g (impurity content 10%) was treated with hydrochloric acid. A gas with an unpleasant odor was released, which was passed through concentrated sulfuric acid. The resulting new gas with a pungent odor was completely absorbed by the concentrated barium hydroxide solution. This resulted in a white precipitate. Determine the composition and weight (g) of the sediment.
FeS + 2HCl → FeCl2 + H2S ↑
H2S + 3H2SO4conc → 4SO2 ↑ + 4H2O
SO2 + Ba (OH) 2conc → BaSO3 ↓ + H2O
m (FeS) pure = 9.8 x 0.9 = 8.82 g
n (FeS) = 8.82 / 88 = 0.1 mol
n (FeS) = n (H2S) = 0.1 mol
n (SO2) = n (H2S) x 4 = 0.4 mol = n (BaSO3)
⇒ m (BaSO3) = 0.4 x (137 + 32 + 48) = 86.8 g
Answer: the precipitate is barium sulfite, its mass is 86.8 g.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.