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The percentage of water of crystallization in ZnSO4....

The percentage of water of crystallization in ZnSO4.7H2O is?
[Zn = 65, S = 32, O = 16, H = 1]

A.

33%

B.

44%

C.

55%

D.

87%

Correct answer is B

molar mass of water [7H2O] = 7[ 2 * 1 + 16] → 7 * 18 = 126g/mol

molar mass of ZnSO4.7H2O = [65 * 1] + [32 * 1] + [16 * 4] + 7[ 2 * 1 + 16] 

→ 65 + 32 + 64 + 126 = 287g/mol

percentage of water of crystallization = massofwaterofcrystallizationmassofhydratedcompound100

126287100 = 43.9

≈ 44%