what are the boiling point and freezing point of a 3.17 m solution of naphthalene in benzene
Look up boiling point, freezing point, Kf, and Kb for benzene.
delta T = Kf*m
Subtract from normal freezing point.
delta T = Kb*m
Add to normal boiling point.
To determine the boiling point and freezing point of a solution, you will need to consider the colligative properties of the solution. These properties depend on the concentration of solute particles, regardless of their identity.
In this case, you have a solution of naphthalene in benzene with a concentration of 3.17 m.
The boiling point elevation and freezing point depression formulas can be used to calculate the changes in boiling point and freezing point due to the presence of the solute.
Boiling Point Elevation:
ΔTb = kb * m
Freezing Point Depression:
ΔTf = kf * m
Where:
ΔTb is the change in boiling point
ΔTf is the change in freezing point
kb is the molal boiling point constant
kf is the molal freezing point constant
m is the molality of the solution (moles of solute per kg of solvent)
To obtain the boiling point and freezing point of the solution, you need to know the values of the molal boiling point constant and the molal freezing point constant for benzene.
For benzene, the molal boiling point constant (kb) is approximately 2.53 °C/m.
The molal freezing point constant (kf) for benzene is roughly 5.12 °C/m.
Now, you can use the above formulas to calculate the boiling and freezing point changes:
Boiling Point Elevation:
ΔTb = kb * m
ΔTb = 2.53 °C/m * 3.17 m
Freezing Point Depression:
ΔTf = kf * m
ΔTf = 5.12 °C/m * 3.17 m
To find the boiling point of the solution, add the calculated boiling point elevation to the boiling point of pure benzene.
Boiling point of solution = boiling point of pure benzene + ΔTb
To find the freezing point of the solution, subtract the calculated freezing point depression from the freezing point of pure benzene.
Freezing point of solution = freezing point of pure benzene - ΔTf
Using this method, you can determine the boiling point and freezing point of the 3.17 m solution of naphthalene in benzene.