Boiling Point Calculator

Find boiling point at a new pressure (Clausius-Clapeyron).

Known pressure P₁ (kPa)

Boiling point at P₁ (K)

ΔH vaporization (J/mol)

New pressure P₂ (kPa)

Boiling point at P₂ (K) 366.55

Boiling point at P₂ (°C) 93.404

Formula: 1/T₂ = 1/T₁ − (R/ΔH)·ln(P₂/P₁)

Step-by-step with your numbers:

1. Values used:

2. Known pressure P₁ = 101.3 kPa

3. Boiling point at P₁ = 373.15 K

4. ΔH vaporization = 40,700 J/mol

5. New pressure P₂ = 80 kPa

7. Boiling point at P₂ = 366.55K

8. Boiling point at P₂ = 93.404°C

Did we solve your problem today?

Find how a liquid's boiling point shifts when pressure changes.

The math behind it

Clausius-Clapeyron: 1/T₂ = 1/T₁ − (R ÷ ΔHvap) × ln(P₂ ÷ P₁).

Water at 80 kPa → boils near 366 K (≈93 °C).

Lower pressure?

Lowers the boiling point — that's why water boils cooler at altitude.