Answer:
Molality for the solution is 1.57 m
Explanation:
Molality is mol of solute in 1kg of solvent.
20.3 % by mass means that 20.3 g of solute (FeCl₃) are contained in 100 g of solution..
Let's determine the mass of solvent.
Mass of solution = Mass of solvent + Mass of solute
100 g = Mass of solvent + 20.3 g
100 g - 20.3 g = Mass of solvent → 79.7 g
Let's convert the mass in g to kg
79.7 g . 1kg / 1000 g = 0.0797 kg
Let's determine the moles of solute (mass / molar mass)
20.3 g / 162.2 g/mol = 0.125 mol
Molality = 0.125 mol / 0.0797 kg → 1.57 m
