Boiling Point Elevation Calculator

Inputs

Solvent

Kb (°C·kg/mol)

Boiling Point pure (°C)

Molality mode

Compute from masses

I know molality m

van ’t Hoff factor (i)

Decimals

Solute mass (g)

Molar mass (g/mol)

Solvent mass (g)

Output temperature unit

How it works

The relation is ΔT_b = i · K_b · m where i is the van ’t Hoff factor, K_b is the ebullioscopic constant of the solvent in °C·kg/mol, and m is the molality of the solute.

Molality m = \u2061 moles\_solute / kg\_solvent
Final boiling point T_b,solution = T_b,pure + ΔT_b
Applies to dilute solutions of nonvolatile solutes

FAQs

1) What is the ebullioscopic constant Kb?

It is a solvent specific proportionality constant in °C·kg/mol that relates molality to boiling point elevation.

2) When should I adjust the van ’t Hoff factor?

Use i greater than 1 for electrolytes that dissociate into multiple ions. For nonelectrolytes leave i as 1.

3) Can I enter molality directly?

Yes choose the option to provide m directly if you already calculated it elsewhere.

4) Are these results valid for concentrated solutions?

The relation is best for dilute solutions. Strongly concentrated solutions may require activity coefficients.

5) What preset values are used for common solvents?

Water ethanol benzene cyclohexane chloroform and carbon tetrachloride are included with widely cited Kb and boiling points. You can override them anytime.

6) Why do I sometimes get a very large elevation?

Check your units especially molar mass and solvent mass. Large m or high i will increase ΔTb.