Calculate the freezing point of 0.15 m calcium chloride aqueous solution. Assume that the molal freezing point depression constant of water is 1.86°C·kg/mol and that the freezing point of water is 0.00°C
To calculate the freezing point of a solution, we need to use the freezing point depression equation:
ΔT = Kf * m
Where:
ΔT is the change in freezing point of the solvent (in this case water)
Kf is the molal freezing point depression constant of the solvent (water)
m is the molality of the solute (calcium chloride)
In this case, we know that the molal freezing point depression constant of water is 1.86°C·kg/mol, and we need to find the freezing point of a 0.15 m calcium chloride solution.
Substituting the values in the equation, we get:
ΔT = 1.86°C·kg/mol * 0.15 mol/kg
ΔT = 0.279°C·kg/mol
Since the freezing point depression is the change in temperature, we can find the freezing point by subtracting the depression from the freezing point of water:
Freezing point = 0.00°C - 0.279°C = -0.279°C
Therefore, the freezing point of a 0.15 m calcium chloride aqueous solution is approximately -0.279°C.