Final answer:
To calculate the molality of a solution, convert the mass percentage to grams, calculate the moles of solute, and divide by the mass of the solvent in kilograms.
Step-by-step explanation:
To calculate the molality of a solution, we need to know the moles of solute and the mass of the solvent. In this case, the solute is hydrochloric acid (HCl) and the solvent is water.
The first step is to convert the mass percentage of the solution to grams. We can assume that there is 100g of the solution, so we have 16.5g of HCl. Next, we calculate the moles of HCl using its molar mass of 36.5 g/mol. We divide the mass of HCl by its molar mass:
moles of HCl = (16.5g HCl) / (36.5 g/mol) = 0.452 moles
Finally, we calculate the molality of the solution by dividing the moles of solute by the mass of the solvent in kilograms:
molality = (0.452 mol) / (1.50 kg) ≈ 0.301 mol/kg ≈ 0.30 m
For a 16.5% aqueous solution of hydrochloric acid, the molality is approximately 0.30 m.