The solubility of a compound in water is found to be 7.26 grams per 100.0 grams of water at 25oC. Calculate the molality of the compound in a saturated aqueous solution at 25oC

Question

The solubility of a compound (molar mass = 175 g/mol) in water is found to be 7.26 grams per 100.0 grams of water at 25^oC. Calculate the molality of the compound in a saturated aqueous solution at 25^oC

Molar mass of the compound is 175 g/mol

Answer 1

Molality = moles of solute / kg solvent

First, we find moles of solute:

7.26 g x 1 mol/175 g = 0.0415 moles

Next, we find kg of solute:

100.0 g H2O x 1 kg/1000 g = 0.1000 kg solvent

Finally, we divide moles by kg to obtain molallity:

Molality = 0.0415 moles / 0.1000 kg = 0.415 m