Using a mass of 500.0 g of water, what is the molality of NaClO₄ in a solution made using 125 g of sodium perchlorate monohydrate?

Question

Quizplus · Accepted Answer

Molality (m) is calculated as moles of solute per kilogram of solvent. The molar mass of NaClO4·H2O is approximately 140.46 g/mol. Thus, 125 g of NaClO4·H2O is about 0.890 moles. The mass of water is 500.0 g, which is 0.500 kg. Therefore, molality = 0.890 moles / 0.500 kg = 1.78 m.

Using a Mass of 500