The equation for lowering the freezing point of a solvent is given in your manual. Given that the freezing point for the pure solvent is 79.4 °C , the molality is 0.1 m , and the freezing point depression constant is 6.9 °C/m , determine the freezing temperature for the naphthalene solution.
Tf= 79.4 oC
m=0.1m
Kf= 6.9 oC
What is delta T?
delta T= 0.1m(6.9 oC)= 0.69 ?
Yes, delta T is 0.69.
Then new freezing point is 79.4-0.69 = ?
If your prof watches significant figures be careful with the final answer.
зЭУш
Yes, that's correct. ΔT, or the freezing point depression, is calculated by multiplying the molality (m) by the freezing point depression constant (Kf).
In this case, ΔT = 0.1 m * 6.9 °C/m = 0.69 °C.
Yes, you are correct! The equation for calculating the freezing point depression is:
ΔT = Kf * m
Where ΔT is the freezing point depression, Kf is the freezing point depression constant, and m is the molality of the solution.
In this case, the molality (m) is 0.1 m and the freezing point depression constant (Kf) is 6.9 oC/m.
So, by substituting these values into the equation, we have:
ΔT = 0.1 m * 6.9 oC/m = 0.69 oC
Therefore, the freezing temperature for the naphthalene solution can be determined by subtracting the freezing point depression (ΔT) from the freezing point of the pure solvent:
Freezing temperature = Tf - ΔT
Substituting the given value for the freezing point of the pure solvent (Tf = 79.4 oC) and the calculated freezing point depression (ΔT = 0.69 oC), we have:
Freezing temperature = 79.4 oC - 0.69 oC = 78.71 oC