Answer:
0.556 °C.
Step-by-step explanation:
The freezing point depression of a solution can be calculated using the equation:
ΔTf = Kf x molality
Where ΔTf is the change in freezing point, Kf is the molal freezing point depression constant, and molality is the concentration of solute in mol/kg.
For magnesium chloride, Kf = 1.853 °C/molal. The molality of the solution can be calculated as follows:
molality = moles of solute / mass of solvent (in kilograms)
= 0.300 mol / (0.300 mol x 1000 g/mol) = 0.300 g/1000 g = 0.0003 kg/kg = 0.300 mol/kg
Now, substituting the values into the equation:
ΔTf = Kf x molality
= 1.853 °C/molal x 0.300 mol/kg
= 0.556 °C
So the freezing point of the 0.300 molal aqueous solution of magnesium chloride will be lower than the freezing point of pure water by 0.556 °C.
ALLEN