Chemistry - Stoichiometry Question with Solution | TestHub
A sample of impure (Molar mass ) containing some inert impurities, is completely reduced by to metallic iron. The gas required for this reduction is generated by reacting of formic acid (HCOOH) with excess concentrated . Assuming yield for the generation reaction and yield for the reduction reaction, what is the percentage purity of the sample? (Atomic mass: ).
Answer:
Solution:
The reactions are:
1. HCOOH(l) CO(g) + H₂O(l)
2. Fe₂O₃(s) + 3CO(g) 2Fe(s) + 3CO₂(g)
Moles of HCOOH = .
Theoretical moles of CO = .
Actual moles of CO produced (80% yield) = .
Let be moles of pure Fe₂O₃.
From reaction (2), 1 mol Fe₂O₃ requires 3 mol CO.
The CO consumed to reduce moles of Fe₂O₃ at 90% yield is:
Actual moles of CO supplied =
.
Mass of pure Fe₂O₃ = .
Percentage purity = .
