Final answer:
c. 0.2. To calculate the molality of an acetic acid solution, divide the number of moles of acetic acid (0.1332 mol) by the kilograms of water (0.725 kg), resulting in a molality of approximately 0.2 m, which corresponds to selection C.
Step-by-step explanation:
To find the molality of the acetic acid (CH3COOH) solution, we first need to calculate the number of moles of acetic acid. Molality is defined as the number of moles of solute per kilogram of solvent. The molar mass of acetic acid is approximately 60.05 g/mol, so with 8 grams of acetic acid, we can calculate the moles as follows:
Number of moles = mass (g) / molar mass (g/mol) = 8 g / 60.05 g/mol = 0.1332 mol
Since the solvent is water with a mass of 725 grams (0.725 kg), we can now calculate the molality:
Molality (m) = moles of solute / kilograms of solvent = 0.1332 mol / 0.725 kg = 0.1837 m
This value is closest to option C, 0.2 m, on the multiple choice selections provided. Therefore, the molality of the solution is approximately 0.2 m.