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JAMB Chemistry 1991 Question 3

Question 3

Mole Concept and Stoichiometry

An iron ore is known to contain 70.0% Fe2O3. The mass of iron metal which can be theoretically be obtained from 80 kg of the ore is [Fe = 56, O = 16].

  1. A.35.0 kg
  2. B.39.2kg
  3. C.70.0 kg
  4. D.78.4 kg
Show the answer and explanation

Answer: B (39.2kg)

Explanation

Mass of Fe2O3 = 70% of 80 kg = 56 kg. Iron is 112/160 of Fe2O3, so iron = 56 × 112/160 = 39.2 kg.