The percentage of water of crystallization in ZnSO\(_4\).7H\(_2\)O is?

[Zn = 65, S = 32, O = 16, H = 1]

  • A 33%
  • B 44%
  • C 55%
  • D 87%
jamb 2009chemistry

The correct answer is B. 44%

molar mass of water [7H\(_2\)O] = 7[ 2 * 1 + 16] â†’ 7 * 18 = 126g/mol

molar mass of ZnSO\(_4\).7H\(_2\)O = [65 * 1] + [32 * 1] + [16 * 4] + 7[ 2 * 1 + 16] 

→ 65 + 32 + 64 + 126 = 287g/mol

percentage of water of crystallization = \(\frac{mass of water of crystallization}{mass of hydrated compound} * 100%\)

→ \(\frac{126}{287} * 100\) = 43.9

≈ 44%

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