Boiling Point Elevation Calculator
Calculate how much a solute raises the boiling point of a solvent using ΔTb = i·Kb·m.
How it works
ΔTb = i · Kb · m · new boiling point = 100 °C + ΔTb (water)
Dissolving a non-volatile solute raises a liquid's boiling point — a colligative property that depends on the number of dissolved particles, not their identity. Kb is the solvent's ebullioscopic constant (0.512 °C·kg/mol for water) and the van 't Hoff factor i counts how many particles each formula unit releases: 1 for sugar, about 2 for NaCl.
Worked example
A 1 mol/kg aqueous solution of a non-electrolyte (i = 1) with Kb = 0.512: ΔTb = 1 × 0.512 × 1 = 0.512 °C, so water boils at about 100.51 °C.
Sources: Boiling-point elevation — Wikipedia
Frequently asked questions
What is the van 't Hoff factor?
It is the number of particles a solute splits into when it dissolves. Sugar stays as one molecule (i = 1); NaCl breaks into Na⁺ and Cl⁻ (i ≈ 2); CaCl₂ gives three ions (i ≈ 3).
Why does salt raise the boiling point?
Dissolved particles lower the solvent's vapour pressure, so a higher temperature is needed to reach atmospheric pressure and boil. More particles mean a bigger effect.
What is Kb for other solvents?
Kb is specific to each solvent: 0.512 °C·kg/mol for water, 2.53 for benzene and 2.02 for chloroform. Enter the value for your solvent to get the right elevation.
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