If the freezing point of pure toluene is -95.15 oC and its freezing point depression constant is -8.38 oC/molal, what is the freezing point of a solution made by dissolving 39.338g of anthracene (C14H10) in 150.0mL of toluene? (Density of toluene = 0.8669g/mL)

mol anthracene = grams/molar mass

grams toluene = volume x density
molality = mol anthracene/kg toluene.
delta T = Kf*m. Solve for delta T.
Subtract from zero to find new freezing point.

To find the freezing point of the solution, we need to consider the freezing point depression caused by the presence of the solute. The formula to calculate the freezing point depression (∆Tf) is given by:

∆Tf = Kf * molality

where:
∆Tf = freezing point depression
Kf = freezing point depression constant
molality = moles of solute / mass of solvent (in kg)

First, let's find the moles of anthracene in the solution:
- Convert the mass of anthracene from grams to moles using its molar mass:
Molar mass of anthracene (C14H10) = (12 * 14) + (1 * 10) = 178 g/mol
Moles of anthracene = mass of anthracene / molar mass of anthracene
= 39.338 g / 178 g/mol

Next, let's find the mass of toluene in the solution:
- Convert the volume of toluene from mL to grams using its density:
Mass of toluene = volume of toluene * density of toluene
= 150.0 mL * 0.8669 g/mL

Now, let's calculate the molality:
- Convert the mass of toluene from grams to kilograms:
Mass of toluene (in kg) = mass of toluene (in g) / 1000

- Calculate the molality using the moles of anthracene and the mass of toluene (in kg):
Molality = moles of anthracene / mass of toluene (in kg)

Finally, we can calculate the freezing point depression (∆Tf):
- Multiply the molality by the freezing point depression constant:
∆Tf = Kf * molality

To find the freezing point of the solution:
- Subtract the freezing point depression from the freezing point of pure toluene:
Freezing point of solution = Freezing point of pure toluene - ∆Tf

Now, let's plug in the values and calculate the freezing point of the solution.