Boiling Point Reference
Search boiling points and run elevation calculations.
A searchable boiling point library plus the two colligative property calculations that come with it: boiling point elevation (ΔTb = Kb·m·i) and freezing point depression (ΔTf = Kf·m·i), with tabulated constants for 14 solvents.
Molality (mol per kg of solvent) is used instead of molarity because it does not change when the solution is heated or cooled.
How to Use the Boiling Point Reference
1
Pick the calculation. Choose boiling point elevation, freezing point depression, the compound boiling point table, or the Kb and Kf constant table.
2
Enter the solution details. Select a solvent, then enter the solute mass, solute molar mass, solvent mass, and van 't Hoff factor.
3
Read the shifted temperature. The result gives the molality, ΔTb and ΔTf, and the new boiling and freezing points of the solution.
What is the Boiling Point Reference?
The boiling point reference combines a searchable table of common solvent and compound boiling points with a boiling point elevation calculator based on ΔTb = Kb·m·i. Look up a solvent, or calculate how much a dissolved solute raises the boiling temperature.
Boiling point elevation is a colligative property: it depends on the number of dissolved particles, not their identity. The van 't Hoff factor i captures ionic dissociation, which is where most students lose points on these problems.
Common Uses
- Look up boiling points of common solvents
- Calculate boiling point elevation for a solution
- Compare volatility when choosing a lab solvent
- Practice colligative property problems
How to Solve It by Hand
Manual calculation is still important: identify the known variables, convert units before substitution, apply the equation, and check whether the result is chemically reasonable. The most common mistakes are inconsistent units, constants rounded too early, and skipping the interpretation step.
Practice Prompt
Try changing the default values and ask the lower-right chemistry chat why the result increased or decreased. That turns the calculator from a number machine into a study loop.
Dissolving a non-volatile solute raises a solvent's boiling point by ΔTb = Kb × m × i, where Kb is the ebullioscopic constant, m is molality in mol per kg of solvent, and i is the van 't Hoff factor.
It is the number of particles each formula unit releases in solution: 1 for non-electrolytes such as sugar, 2 for NaCl, and 3 for CaCl2. Colligative properties count dissolved particles, not their chemical identity.
Molality is moles per kilogram of solvent, which does not change when the solution is heated or cooled. Molarity is volume based, and volume expands with temperature, so it would drift during a boiling point measurement.
It is the same idea with the opposite sign: ΔTf = Kf × m × i lowers the freezing point. Kf is generally much larger than Kb for the same solvent, which is why freezing point depression is the more sensitive method for determining molar mass.
Yes. All the values in the reference table are quoted at 1 atm. Lowering the pressure lowers the boiling point, which is exactly how a rotary evaporator removes solvent at low temperature.