Assuming 100% dissociation, calculate the freezing point and boiling point of 2.91 m K3PO4(aq).
delta T = i*Kf*m
i = 4. Solve for delta T and subtract from -0C to find new freezing point.
delta T = i*Kb*m
i = 4. Solve for delta T and add to 100 to find new boiling point.
To calculate the freezing point and boiling point of a solution, you need to use the formula for the change in boiling point and freezing point elevation. These formulas are based on the molality of the solution and a constant, which is specific to the solvent.
The formula for the change in boiling point (ΔTb) is given by:
ΔTb = Kb * m
And the formula for the change in freezing point (ΔTf) is given by:
ΔTf = Kf * m
Where:
- ΔTb is the change in boiling point
- ΔTf is the change in freezing point
- Kb is the boiling point elevation constant for the solvent (in this case, water)
- Kf is the freezing point depression constant for the solvent (in this case, water)
- m is the molality of the solution, which is defined as the number of moles of solute per kilogram of solvent
Now, we need to find the boiling point elevation constant (Kb) and freezing point depression constant (Kf) for water. The values are approximately 0.512 °C/m for Kb and 1.86 °C/m for Kf.
Given that the molality (m) of the solution is 2.91 m K3PO4(aq), we can now calculate the change in boiling point (ΔTb) and change in freezing point (ΔTf).
ΔTb = 0.512 °C/m * 2.91 m
ΔTf = 1.86 °C/m * 2.91 m
Calculating the values:
ΔTb = 1.49112 °C
ΔTf = 5.4026 °C
To find the freezing point, subtract the calculated ΔTf from the normal freezing point of water (0 °C):
Freezing Point = 0 °C - ΔTf
Freezing Point = 0 °C - 5.4026 °C
Freezing Point = -5.4026 °C
To find the boiling point, add the calculated ΔTb to the normal boiling point of water (100 °C):
Boiling Point = 100 °C + ΔTb
Boiling Point = 100 °C + 1.49112 °C
Boiling Point = 101.49112 °C
Therefore, assuming 100% dissociation, the freezing point of the 2.91 m K3PO4(aq) solution is approximately -5.4026 °C, and the boiling point is approximately 101.49112 °C.