Boiling Point Elevation Calculator Formula

Understand the math behind the boiling point elevation calculator. Each variable explained with a worked example.

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Formulas Used

Boiling Point Elevation

delta_tb = vant_hoff * kb_const * molality

New Boiling Point

new_bp = bp_pure + vant_hoff * kb_const * molality

Variables

VariableDescriptionDefault
kb_constEbullioscopic Constant (Kb)(C-kg/mol)0.512
molalityMolality(m)1
vant_hoffVan't Hoff Factor (i)1
bp_pureBoiling Point of Pure Solvent(C)100

How It Works

How to Calculate Boiling Point Elevation

Formula

delta_Tb = i × Kb × m

For water, Kb = 0.512 C-kg/mol. The boiling point rises when solute is added.

Worked Example

1 m glucose (i=1) in water.

kb_const = 0.512molality = 1vant_hoff = 1bp_pure = 100
  1. 01delta_Tb = 1 × 0.512 × 1 = 0.512 C
  2. 02New BP = 100 + 0.512 = 100.512 C

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