Assuming that each system behaves ideally, which solution (.25m KCl or .25m C3H8O3) would have the lower freezing point? Explain.
This question depends upon you knowing the number of particles (ions) produced when placing them in water.
delta T = i*Kf*molality.
i # particles.
To determine which solution would have the lower freezing point, we need to compare their freezing point depression values. The freezing point depression is directly proportional to the concentration of the solute particles in a solution.
To calculate the freezing point depression, we can use the equation:
ΔTf = Kf * m
Where:
ΔTf = Freezing point depression
Kf = Cryoscopic constant (constant for the solvent)
m = Molality of the solute particles (moles of solute per kilograms of solvent)
In this case, we have two solutions:
1. 0.25 M KCl (potassium chloride)
2. 0.25 M C3H8O3 (glycerol)
Since both solutions have the same molarity (0.25 M), the molality (m) will also be the same for both solutions.
Now, we need to consider the cryoscopic constants (Kf) for KCl and C3H8O3. The cryoscopic constant is specific to each solvent and is usually given.
For KCl, the cryoscopic constant is typically around 1.86 °C/m.
For C3H8O3 (glycerol), the cryoscopic constant is approximately 1.86 °C/m as well.
Since the cryoscopic constants (Kf) are the same for both solutions, and the molality (m) is the same, the freezing point depression (ΔTf) will be the same for both solutions.
Therefore, both the 0.25 M KCl solution and the 0.25 M C3H8O3 solution will have the same freezing point depression and, consequently, the same freezing point.