The gas obtained from the combustion of 6.4 g of sulfur was absorbed in 200 g of concentrated potassium hydroxide solution. Determine the mass fraction of the formed salt in the solution.
S + O2 → SO2
SO2 + 2KOHconc → K2SO3 + H2O
n (S) = 6.4 / 32 = 0.2 mol – deficient
n (KOH) = 200 / (39 + 17) = 3.57 mol – in excess
m (K2SO3) = 0.2 x (39 x 2 + 32 + 48) = 31.6 g
m solution = 200 + 0.2 x 64 = 212.8 g
ω (K2SO3) = 31.6 / 212.8 x 100% = 14.85%
Answer: the mass fraction of salt (potassium sulfite) formed in the solution is 14.85%.
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.