A solution of naphthalene (C10H8, 128.17 g/mol) in benzene (C6H6, 78.11g/mol) has a freezing point temperature of 3.41 C. Calculate the mass percent (%m/m) of naphthalene in this solution and the boiling point of the solution.
Benzene
Kf: 5.12 C/m
Kb: 2.53 C/m
Tf: 5.53 C
Tb: 80.10 C
Density: 0.876 g/cm^3
dTfreezing = 5.53-3.41 = Kf*m. You know Kf and dT, solve for molality.
Then using the same m, plug that into dTboiling = Kb*m. Knowing Kb and m, you can calculate delta T. Add delta T to the normal boiling point to find the new b.p.
I don't see information to calculate grams either solvent or solute.
The density you list is the density of what?
To calculate the mass percent (%m/m) of naphthalene in the solution, we need to determine the mass of naphthalene and the total mass of the solution.
1. First, let's calculate the molality (m) of the solution.
The formula for molality is:
m = (moles of solute) / (mass of solvent in kg)
The mass of benzene can be calculated using its density:
Mass of benzene = density × volume
= 0.876 g/cm^3 × volume (in cm^3)
Since the volume is not given, we cannot calculate the exact mass. We'll proceed assuming we have a known volume of the solution.
2. To calculate the molality, we need to convert the freezing point depression (ΔTf) to molality.
ΔTf = Kf × m
Rearranging the equation, we have:
m = ΔTf / Kf
m = (3.41 C) / (5.12 C/m)
3. Next, we can calculate the moles of naphthalene based on the molality and molal constant of benzene.
Moles of naphthalene = m × (mass of benzene in kg)
We can calculate the mass of benzene in kg by dividing the mass of benzene by 1000.
4. Finally, we can calculate the mass percent of naphthalene.
%m/m = (mass of naphthalene) / (mass of solution) × 100
To calculate the boiling point of the solution, we're given the boiling point constant (Kb) of benzene. The equation to calculate boiling point elevation (ΔTb) is similar to the freezing point depression equation:
ΔTb = Kb × m
To determine the boiling point of the solution, we add the boiling point elevation to the boiling point of the pure solvent:
Tb = Tb of solvent + ΔTb
Substituting the values, we can calculate the boiling point of the solution.
Please provide the volume of the solution or any additional information required to proceed with the calculations.