what is the boiling point of 0.212 m lactose in water?
delta T = Kb*m
Solve for delta T and add to 100 C to find the new boiling point.
To determine the boiling point of a solution, you need to consider the boiling point elevation caused by the solute. The boiling point elevation is a colligative property, meaning it depends on the concentration of the solute particles, not their identity.
To calculate the boiling point elevation, you can use the following formula:
ΔTb = Kb * m * i
Where:
ΔTb is the boiling point elevation
Kb is the molal boiling point elevation constant (for water, it is 0.512 °C/m)
m is the molality of the solution (moles of solute per kilogram of solvent)
i is the van't Hoff factor, which represents the number of particles the solute dissociates into in solution (for lactose, i is 1)
First, you need to calculate the molality (m) of the lactose solution. Molality is given by the formula:
m = mol solute / kg solvent
Here, you are given that the concentration of lactose is 0.212 mol/L. To convert this to mol/kg, you need to know the molecular weight of lactose. The molecular weight of lactose is approximately 342.29648 g/mol.
Using these values, you can calculate the molality as follows:
m = (0.212 mol/L) / (342.29648 g/mol / 1000) = 0.620 mol/kg
Now, you can calculate the boiling point elevation (ΔTb) using the formula mentioned above:
ΔTb = (0.512 °C/m) * (0.620 mol/kg) * 1 = 0.31744 °C
Finally, you can add the boiling point elevation to the normal boiling point of water (100 °C) to find the boiling point of the lactose solution:
Boiling point = 100 °C + 0.31744 °C = 100.31744 °C
Therefore, the boiling point of the 0.212 m lactose solution in water is approximately 100.32 °C.
To calculate the boiling point of a solution, you can use the formula for boiling point elevation, which states that the boiling point elevation (∆Tb) is directly proportional to the molality of the solute (∆Tb = Kbm), where Kb is the molal boiling point elevation constant and m is the molality of the solute.
First, you need to find the molality (m) of the lactose in water. Molality is defined as the moles of solute per kilogram of solvent. In this case, we need to calculate the molality of the lactose solution.
To calculate the molality, you will need to know the molar mass of lactose and the mass of the solution.
1. Determine the molar mass of lactose: The molar mass of lactose (C12H22O11) is the sum of the molar masses of carbon (C), hydrogen (H), and oxygen (O) atoms. Multiply the atomic mass of each element by the number of atoms, then sum them up. This will give you the molar mass of lactose.
2. Calculate the mass of the solution: If you know the mass of the solute and the mass of the solvent, you can add them together to find the total mass of the solution.
3. Calculate the moles of lactose: Divide the mass of lactose by its molar mass. This will give you the number of moles of lactose.
4. Calculate the molality: Divide the number of moles of lactose by the mass of the solvent (in kilograms). This will give you the molality of the lactose solution.
Once you have calculated the molality (m), you can use the molal boiling point elevation constant (Kb) to find the boiling point elevation (∆Tb).
The boiling point elevation is calculated as follows: ∆Tb = Kb * m
Finally, add the boiling point elevation (∆Tb) to the boiling point of pure water (which is 100 degrees Celsius at sea level) to find the boiling point of the lactose solution.
Note: The molal boiling point elevation constant (Kb) is a property of the solvent and can vary. For water, the value is approximately 0.51 degrees Celsius/m.