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JAMB Chemistry 1989 Question 16

Question 16

Mole Concept and Stoichiometry

A hydrated salt of formula MSO4.xH2O contains 45.3% by mass of water of crystallisation. Calculate the value of x. [M = 56, S = 32, O = 16, H = 1]

  1. A.3
  2. B.5
  3. C.7
  4. D.10
Show the answer and explanation

Answer: C (7)

Explanation

MSO4 = 152. 18x/(152 + 18x) = 0.453, so 18x × 0.547 = 68.9 and x ≈ 7.