Clausius Clapeyron Vapor Pressure Calculator
Estimate saturation vapor pressure at a second absolute temperature from one reference and constant molar vaporization enthalpy.
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Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Apply the integrated ideal-vapor Clausius–Clapeyron approximation with constant entered latent enthalpy.
ln(P2/P1)=−ΔHvap/R×(1/T2−1/T1)
Worked example
If the query temperature equals reference temperature, predicted pressure equals the reference pressure exactly.
Assumptions and input details
Positive pressures/temperatures and constant positive vaporization enthalpy; ideal vapor and negligible liquid molar volume. No critical-region, sublimation, nonideal, mixture or fitted Antoine-equation correction. Log pressure ratio is restricted to ±100.
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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