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Calculate the molality of a 20% (by mass) aqueous solution of KI. (Molar mass of KI = 166 g/mol.)

1. 1.08
2. 1.48
3. 1.51
4. 1.35

Correct answer: 1.51

Solution

Moles of KI = 20/166 = 0.1205; water = 0.080 kg; molality = 0.1205/0.080 = 1.51 m.

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